Table of Content

20 April 2014, Volume 23 Issue 2

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Prediction of pasture reviving period and analysis of its climate potential productivity

DUAN Xiao-feng, ZHANG Lei, WEI Jian-guo, ZHU Yong-ning, YANG Yang, JIN Fei

2014, 23(2):  1-8.  DOI: 10.11686/cyxb20140201

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To find reasonable and effective control measures for development of livestock and pasture in our region and to keep an ecological balance and healthy development of pasture, to control soil erosion, develop climate resources, achieve pasture resources sustainable use and improve the ecological environment, a regression model was built in the context of climate change, by applying SPSS to explore the revival indicators of Ningxia representative natural pasture (Gramineae, Leguminous). Climate potential productivity was calculated using the Miami and Tharnthwaite Memorial models. The reviving period of Gramineae was the date that sliding average temperatures of five days stably exceeded the first day of 0℃ accumulated temperatures of 11-17 days later. Legumes turned green 4 days before to 6 days after the forecast date. Attenuation of light potential production was smaller than that of water which was the main limiting factor of grass climate potential productivity. Pasture re-greened earlier and climate potential productivity increased slightly with a trend of temperature rising and rainfall increasing.

Soil C/P distribution characteristics of alpine steppe ecosystems in the Qinhai-Tibetan Plateau

WANG Jian-lin, ZHONG Zhi-ming, WANG Zhong-hong, YU Cheng-qun, SHEN Zhen-xi, ZHANG Xian-zhou, HU Xing-xiang, Dacizhuoga

2014, 23(2):  9-19.  DOI: 10.11686/cyxb20140202

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Soil C/P distribution characteristics of alpine steppe ecosystems in the Qinghai-Tibetan Plateau were researched based on data measured at 67 sampling points. 1) The average C/P was 24.45 with variances of 1.05-177.69 In a horizontal direction. It appeared higher in the northwest and lower in the southeast as a macrocosm tendency with distribution characteristics of a staggered pattern. The higher C/P levels appeared mainly in the regions concentrated in the hinterland of the northern parts of the Tibetan Plateau and in the lake basin region at the northern foot of the Himalayas. There were significant differences of C/P among different grass-types and natural transects. 2) The average C/P ratio at different soil depths (0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm) among 19 grassland types were 26.15, 33.59, 30.33 and 22.76, respectively. In a vertical direction, soil depths from aboveground to underground, could be divided into 5 types of C/P distribution patterns (low-high-low-high, low-high-low, high-low-high-low, high-low-high, and high-low) among different grass types. 3) C/P was significantly positively correlated with vegetation coverage, vegetation height, and soil bulk density at depths from 20 to 30 cm, soil water content at depths from 10 to 20 cm, and at depths from 30 to 40 cm and with soil content of HCO₃^-. The C/P ratio was significantly correlated with ≥10℃ accumulated temperature, and with the average annual relative humidity, the underground biomass at soil depths from 10 to 20 cm, soil bulk density at depths from 0 to 10 cm, soil water content at depths from 0 to 10 cm. It was negatively correlated with soil content of available K, organic matter, total organic carbon and hydrolysable carbon.

Effect of grazing intensity on ecological stoichiometry of Deyeuxia angustifolia and meadow soil

ZHANG Ting, WENG Yue, YAO Feng-jiao, SHI Yin-tao, CUI Guo-wen, HU Guo-fu

2014, 23(2):  20-28.  DOI: 10.11686/cyxb20140203

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The role of grazing on the stoichiometry traits of soil and plants in Deyeuxia angustifolia meadows of the northeast Sanjiang Plain were studied under different grazing intensities. We determined the C, N, and P contents and the C/N ratios of plant and soil to explore how grazing affects the stoichiometry traits and nutrient cycling rates in an ecosystem. 1) With an increase of grazing intensity, the N and P contents of ground-living and standing litter was increased. The N content of leaves increased with grazing while the stem changes were not obvious. The change of C, N, and P contents of roots in the 0-10 cm soil layer was more sensitive than that in the 10-20 cm soil layer. Grazing reduced the content of total soil carbon while the TN (total N) content of the soil surface initially increased but then decreased with an increase of grazing intensity, and the minimum value was in heavy grazing. 2) With an increase of grazing intensity, the C/N ratio of the entire plant and the leaves were initially increased but then decreased in June to August, and the smallest value was in moderate grazing, the change of C/N ratio of stems was not obvious, but was smallest in August. 3) Grazing mainly impacted the physical and chemical properties of the surface soil and the roots in it. The C/N ratio was reduced in the 0-10 cm soil layer with an increase of grazing intensity in July to September. The C/N ratio of roots in the 0-10 cm was initially reduced but then increased with an increase of grazing intensity in July and August: moderate grazing had the smallest value, while the N/P ratio had the maximum value.

Comparative study on distributed feature of wild Angelica sinensis resources and the difference in growth characteristics with its cultivars native to Min County of Gansu

ZHAO Rui-ming, CHEN Yuan, GUO Feng-xia, WANG Yang, ZHANG Shang-zhi, WANG Rui-qi

2014, 23(2):  29-37.  DOI: 10.11686/cyxb20140204

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Using methods of route survey and sampling investigation, wild Angelica sinensis resources in Min County were comprehensive surveyed in order to further explore distributed characteristics of the resources, medicinal materials reserves, botanical feature for the wild plant in differently ecological districts of Min County, and to explore its differences in plant morphology and disease resistance with the cultivated A. sinensis. The results showed that the wild A. sinensis populations were found for the first time in three sample sites as Maye forest farm at Sigou Township, the 4th commune of Fanrong village at Mawu Township and Shangshizi Shajin village at Mawu Township and their neighborhood in Min County, Gansu province. The wild A. sinensis only distributed in the Maye and Mayan forestry area of Min County and the distribution area was nearly 17.9 km² with about 1094.9 kg of medicinal materials reserves. There existed no difference in most botanical features between the wild and the cultivars, except for plant height, root size, root color and stem color. Compared to the cultivated A. sinensis plants, morphological parameters of the wild A. sinensis plants were significantly lower (P＜0.01). Leaf number, plant height, the fresh weight of the above ground parts, root diameter, the fresh and the dry weight of root of the wild A. sinensis plants were 64.7%, 64.5%, 47.6%, 28.6%, 26.2% and 38.1% of the cultivated ones dug at the same time, respectively. Disease investigation result showed that incidences of Ditylenchus destructor and other disease were 17.5% and 5.0% respectively in the cultivated A. sinensis plants, but none was found in the wild A. sinensis plants. The above results showed that the wild A. sinensis was valuable basic-materials to breed new A. sinensis varieties with disease resistance, although its productive performance was lower than that of the cultivars. It considered that to explore and protect the wild A. sinensis resources (especially in genuine producing area) is extremely important to breed new varieties of A. sinensis in the future. So it suggests that the related agency should make policy to protect the wild resources found in Min County as soon as possible.

Biomass allocation patterns and allometric relationships of six ephemeroid species in Junggar Basin, China

TAO Ye, ZHANG Yuan-ming

2014, 23(2):  38-48.  DOI: 10.11686/cyxb20140205

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Ephemeroid species are an important and special component of the desert flora in China. The Junggar Basin is the easternmost area where the ephemeroid species distribute in arid areas of central Asia. Up to now, there are very few studies on biomass allocation and the allometric relationships of ephemeroid species. Six species, Allium pallasii, Allium caeruleum, Eremurus inderiensis, Gagea nigra and Tulipa iliensis (all belong to Liliaceae) and Scorzonera pusilla (Asteraceae) were chosen as target plants, and about 20 to 35 individual plants of each species were obtained. The One-way ANOVA and Levene’s test were used to analyze the similarity or difference in biomass allocation among six ephemeroid species. The power function was used to test the relationship between the root to shoot mass ratio (R/S) and plant size (aboveground biomass) and between the reproduction allocation ratio (RAR) and plant size of six species using ordinary least squares (OLS, i.e. Model Type I) regression. The reduced major axis (RMA, i.e. Model Type II) regression was employed to analyze the similarity or difference in allometric relationships among six species using SMARTR software. The results showed that the total individual plant biomass of six species ranged from 0.628 g to 21.144 g, root to shoot mass ratios (R/S) ranged from 0.355 to 3.066, leaf to total plant mass ratios ranged from 0.092 to 0.289, and reproduction allocation ratios (RAR) ranged from 0.111 to 0.649. The biomass ratios of reproduction organ and photosynthetic organ were different among six species, indicating that there was no regular pattern of biomass and its allocation ratios among different families, different genera and different species in a genus. R/S of most species declined markedly with the plant body size, while the RAR showed significant increasing tendency with the body size. Most (40 pairs) of the species pairs (45 pairs in total) of organ biomass represented isometric relationships (i.e. their allometric scaling exponents were 1.0), and the aboveground-belowground biomass pairs, leaf-belowground biomass pairs exhibited common allometric scaling exponents (0.8764 and 0.8585) respectively, showing strong functional convergence. However, they did not show the same allometric relationship of six ephemeroid species, which might be due to the difference in the genetic property determined by the taxonomic position.

The ecological effects of planting Apocynum venetum in the plain desert of the Altay Region, Xinjiang Province

PING Xiao-yan, LIN Chang-cun, BAI Yu, LIU Qi-tang, LU Xin-shi

2014, 23(2):  49-58.  DOI: 10.11686/cyxb20140206

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Climate change and inappropriate human activities such as over grazing and cultivation has led to plant degradation and reduction in ecosystem service function in the Altay Region, Xinjiang Province, China. How to effectively restore the degraded ecosystem and improve the ecosystem service function have become key points for resource protection and land use management. To restore the environment and prevent vegetation degradation, a silvopasture ecosystem was constructed by planting Apocynum venetum in the plain desert. Based on field sampling and in situ measurements, this study compared several important ecosystem service functions such as carbon sequestration and resistance to wind and water erosion in the plain desert using A. venetum planted in 2010 and 2011. Compared with the original plain desert, the A. venetum silvopasture ecosystem significantly increased the leaf net photosynthetic rate and water use efficiency for both plots planted in 2010 and 2011. Planting A. venetum in the plain desert significantly increased the plant carbon density (340% and 460% for 2010 and 2011 respectively compared with the plain desert), which was largely due to the promotion effect of planting A. venetum on the community growth. The total carbon density increased by 23% and 21%, wind erosion modulus decreased by 70.87% and 88.72%, and soil water erosion value decreased by 13.50% and 18.33% in A. venetum plots planted in 2010 and 2011 respectively compared with plain desert. Our results suggested that the construction of silvopasture ecosystem in the plain desert could improve the community structure, increase water use efficiency and carbon sequestration potential, and enhance the resistance to wind and water erosion in the study area. Planting A. venetum could bring both large ecological and economic benefits for the study area.

Correlation study of soil compaction by mowing machine and alfalfa yield

GAO Ai-min, WU Jing-feng, DAI Fei, ZHANG Feng-wei, HAN Zheng-sheng

2014, 23(2):  59-65.  DOI: 10.11686/cyxb20140207

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Soil compaction problems resulted from 1-10 passes of a HW320 mowing machine along the same track in field tests. The correlations between soil bulk density,soil hardness and alfalfa (Medicago sativa) yield were analyzed. Soil bulk density and soil hardness in different depths were increased because of alfalfa soil compaction and the soil bulk density was directly proportional to lg N of the number of compaction times. Alfalfa yield was reduced because of soil compaction. There were negative correlations between soil bulk density and alfalfa yield, which can be represented by quadratic equations. Soil hardness was also negatively correlated with alfalfa yield, the correlation of soil hardness at 0 to 20 cm soil depth with alfalfa yield is high and can be represented by quadratic equations.

Effects of Se-Zn and fulvic acid combined application on nutrient component and amino acids formation of alfalfa

TIAN Chun-li, JIE Xiao-lei, LIU Yan, LIU Fang, GUO Xiao, HU Hua-feng, LIU Shi-liang

2014, 23(2):  66-75.  DOI: 10.11686/cyxb20140208

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A field experiment was conducted to investigate the nutrient component and amino acids formation contents of alfalfa (Medicago sativa) by selenium (Se) and zinc (Zn) and fulvic acid (FA) combined basal application in alfalfa grassland at Zhongmu Town in Zhengzhou City. The experiment was have five treatments: (1) only applied N, P and K fertilizer, and the fertilized amount was N 90 kg/hm², P₂O₅ 120 kg/hm², K₂O 105 kg/hm²; (2) combined application N, P, K fertilizer and FA (FA applied amount was 90 kg/hm²); (3) combined application N, P, K fertilizer and micro-element fertilizer Se, Zn (ZnSO₄·7H₂O applied amount was 15 kg/hm², Na₂SeO₃ applied amount was 0.60 kg/hm²); (4) combined application N, P, K fertilizer, micro-element fertilizer Se, Zn and FA; (5) CK (there was no fertilizer applied). All the fertilizer was applied as basal fertilizer. And collected the first cut of second year alfalfa was measurement samples. The results indicated that appropriate Se-Zn and FA applied amount could significantly increase herbage yield of alfalfa, and the highest herbage yield was raised to 16.28 t/hm² occurred in the NPK+FA+Zn+Se treatment, higher by 42.43% than that of CK. Applying Se-Zn or FA all could significantly increase the alfalfa Se and Zn content and accumulation. Se-Zn and FA combined application could significantly increase the content of alfalfa crude protein and crude ash, but it there was no significantly effect on crude fat, crude fiber and non-nitrogen extract content. Se-Zn and FA combined application could also increase the contents of total amino-acids (TAA) content and Val, Leu, Lys content and Asp, Arg, His, Tyr content, but had less apparent effects on other amino acid under any condition. The results obtained in this study suggest that appropriate Se-Zn and FA combined application could increase the herbage yield and nutrient and amino acids formation contents of alfalfa and it also favor high quality production.

The effect of groundwater depth on the δ¹³C value of constructive species leaf in the lower reaches of the Tarim River

REN Zhi-guo, CHEN Ya-peng, LI Wei-hong, LIU Shu-bao

2014, 23(2):  76-82.  DOI: 10.11686/cyxb20140209

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The δ¹³C values of Populus euphratica and Tamarix spp. in the lower reaches of the Tarim River were measured under different groundwater depth gradients and the effect of groundwater depth diversification on long-term water use efficiency was analyzed. This research provides a scientific basis for degraded ecosystem vegetation conservation and restoration in the lower reaches of the Tarim River. The δ¹³C value in P. euphratica leaves initially increased but then decreased as the groundwater depth varied from 2.4 to 9.1 m. P. euphratica was likely to reduce aboveground biomass to adapt to the intensified drought at 9.1 m. The δ¹³C values in Tamarix spp. leaves gradually increased with increasing groundwater depth, indicating that water use efficiency and the width of the adapted groundwater depth increased as the groundwater depth become deeper. The δ¹³C values of P. euphratica and Tamarix spp. leaves were compared under the conditions of the same groundwater depth and It was found that drought resistance of P. euphratica was weaker than that of T. chinensis with increasing groundwater depth. Under conditions of different groundwater depths, the δ¹³C values of P. euphratica and Tamarix spp. leaves were compared. P. euphratica used different strategies at different groundwater depths to adapt to arid environments, while Tamarix spp. resisted the intensified drought by increasing water use efficiency.

Effects of stepping on soil respiration of Zoysia matrella lawn during the winter dormancy period

XIONG Li, XU Zheng-feng, WU Fu-zhong, YANG Wan-qin, YIN rui, LI Zhi-ping, NI Xiang-yin, XIONG Hai-tao

2014, 23(2):  83-89.  DOI: 10.11686/cyxb20140210

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With the acceleration of urbanization, urban green areas are rapidly expanding. Human stepping is one of the important disturbances impacting on urban green space and may affect the soil respiration and carbon cycle of lawns. Therefore, we choose stepping and control plots in a typical subtropical Zoysia matrella lawn. Soil respiration rates were continuously measured during the winter dormant period using a Li-8100 automatic instrument. Seasonal variations in soil respiration was characterized by a pattern of mono-peak curves, initially decreasing but then increasing. Human stepping significantly reduced the soil respiration rate and temperature sensitivity of soil respiration (Q₁₀) in the Z. matrella lawn during the period of dormancy. Soil respiration of Z. matrella lawn was controlled more by soil temperature than soil moisture over the dormant period. Stepping reduced soil respiration rate of Z. matrella lawn by 53.6% on average. Stepping-induced changes in soil physical properties and growth of Z. matrella might interactively cause the decline in soil respiration.

Redundancy analysis of soil and vegetation of recovered grassland on abandoned land in the desert steppe

WANG Xing, SONG Nai-ping, YANG Xin-guo, CHEN Lin, LIU Bing-ru, QU Wen-jie, YANG Ming-xiu, XIAO Xu-pei

2014, 23(2):  90-97.  DOI: 10.11686/cyxb20140211

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The essence of desertification is that soil quality deteriorates. Loss of soil materials, soil physical and chemical properties, deterioration of biological characteristics and the changing of soil structure are the principal features. The previous degrees and nature of soil desertification have important effects on the process of vegetation recovery and the direction of succession after land is abandoned. To develop a deeper understanding of the relationship between plant and soil environmental factors under different thicknesses of sand bed, we studied the relationship between plant distribution, diversity and major soil factors with the changing of surface sand bed thickness in space by redundancy analysis, taking a recovered grassland on abandoned cultivated land in the desert steppe region of Ningxia as the test area. With an increase of sand bed thickness, the Lespedeza bicolor plant community was substituted by that of Sophora alopecuroides, and the importance of L. bicolor decreased from 0.334 to 0.104 while the importance value of S. alopecuroides increased from 0 to 0.404. The plant diversity index of Margalef, Shannon-Wiener and Pielou were correspondingly increased: the plant diversity index of Margalef increased from 0.32 to 0.79, that of Shannon-Wiener from 0.13 to 0.40,and that of Pielou from 0.11 to 0.22. The main significant soil environment factors affecting plant distribution and diversity were soil salt and calcium carbonate in the 0-10 cm soil layer and soil calcium carbonate in the 10-40 cm soil layer. The change of soil calcium carbonate content on the surface represented the degree of desertification and the stage of degeneration of the zonal sierozem. At present, the form of plant distribution patterns on recovered grassland in abandoned lands, was mainly the result of adaptability of species diffusing and randomly competing under the given constraints of a specific state of soil degradation. The crucial factors were the direct or indirect effects of surface soil environmental factors decided by sand bed thickness, although the direct action of soil nutrients for vegetation were not fully reflected.

Dynamic monitoring of drought based on Temperature Vegetation Dryness Index in Guangdong Province

WANG Ying, WANG Jing-song, YAO Yu-bi, ZHAO Fu-nian

2014, 23(2):  98-107.  DOI: 10.11686/cyxb20140212

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Guangdong Province has been suffering from seasonal drought and the dynamic monitoring of drought by remote sensing data could be an important tool. The EVI-T_S space was constructed by Moderate Resolution Imaging Spectro radiometer (MODIS) data, the dry and wet edges were extracted with a linear fitting method and then the Temperature Vegetation Dryness Index (TVDI) was calculated for Guangdong Province in 2011 and the Temporal-spatial distribution of drought was analyzed. 1) With an increase of the Enhanced Vegetation Index (EVI), the maximum land surface temperature decreased and the difference value between the maximum and minimum land surface temperature also decreased. The maximum and minimum land surface temperature both had an approximately linear relation to the EVI. The seasonal variation of EVI-T_S space was obvious. When the temperature decreased, the EVI-T_S space shrank and with a change of temperature, the intercept of the dry and wet edges changed correspondingly, i.e. the intercept was smaller in winter and bigger in summer. 2) Winter drought was very serious, while spring and autumn drought were also serious to some degree in Guangdong Province in 2011. The drought in winter and spring had similar distribution areas, and the grade weakened gradually from south to north. The drought in coastal areas was more serious than in inland areas. The geographical distribution of autumn drought approximately increased from south to north, which was the opposite to winter and spring droughts. According to the weather data in Guangdong Province, the results of the drought monitoring by remote sensing were in conformity with reality. 3) There was a significant negative correlation between TVDI and soil moisture and the results showed that the soil moisture can be successfully reflected by the TVDI data. The TVDI was negatively correlated with precipitation, temperature and mean relative humidity. TVDI had a high correlation coefficient with precipitation. TVDI was sensitive to precipitation on the station scale, which is a similar trend to the change of TVDI and precipitation in the time series. Continuous precipitation for a certain time was followed by a decline in the TVDI which indicated slight drought only and vice versa.

Integrated risk assessment of snow disaster in the Three Rivers Source Region, China

WANG Shi-jin, WEI Yan-qiang, FANG Miao

2014, 23(2):  108-116.  DOI: 10.11686/cyxb20140213

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The average snow depth, snow day, snow disaster periodicity, slope, livestock density, overloading rate of livestock in winter and spring, grass production, regional GDP and net income of the farmers in 2010 were selected as the main risk factors of snow disaster. A regression model of integrated risk assessment of snow disaster was established and the integrated risks in the Three Rivers Source Region were systematically evaluated using logistic regression methods and the ArcGIS and SPSS software tools. 1) During 1960-1980, the frequency of snow disaster was relatively lower in the Three Rivers Source Region in winter and spring. After 1980, the frequency showed a trend to increase. During 1980-2008, the numbers of snow disasters accounted for 62% of the total numbers in the past 59 years. In spatial distribution, snow disasters were mainly concentrated in the southeastern area of the Three Rivers Source Region. 2) Regression results of integrated risk showed that the average snow depth, snow disaster periodicity, grass production and livestock density had higher importance or with regression coefficients of 2.17, 1.38, 1.27 and 0.92 respectively, while net income of the farmers had lower importance than other factors. 3) The areas with higher integrated risks of snow disaster were located mainly in Yushu, Chengduo, Zaduo and Nangqian counties in southern regions of the Bayan Har Mountains and Gande, Dari, Maqin and Jiuzhi counties between the A'nyemaqen Range and Bayan Har Mountains A'nyemaqen Range in 2010, while the areas with lower integrated risk were concentrated in most areas of no man's land in Hoh Xil and in the Togton river basin. 4) Assessment results of integrated risk of snow disaster accorded with the actual distribution of snow disasters in the Three Rivers Source Region in the past 59 years. This study is of great significance for mitigating the losses from snow disasters and ensuring the sustainable stockbreeding development in pastoral areas. It can provide a scientific basis for mitigation planning pre-disaster and for decision strategies of assistance and recovery post-disaster for the local government departments.

Study on root system development ability of different root-type alfalfa

NAN Li-li, SHI Shang-li, ZHANG Jian-hua

2014, 23(2):  117-124.  DOI: 10.11686/cyxb20140214

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Alfalfa is generally credited as the world’s most important perennial leguminous grass, with a huge potential for development and utilization. Root types of alfalfa are divided into tap rooted, branch rooted, creeping rooted and rhizomatous rooted. Many alfalfa belong to the tap rooted variety, which are fitted to be mowed. The tap rooted alfalfa has an obvious taproot and a vertical standing stem. Many variegated alfalfa belong to branch rooted variety, which are fitted both to be mowed and grazed. The branch rooted alfalfa has many lateral roots extended in a large area and a vertical or semi-vertical standing stem, but has no an obvious taproot. Compared with no-creeping rooted alfalfa, creeping rooted alfalfa has a high resistance on cold, arid, grazing and a large shaped area. The creeping rooted alfalfa has many horizontal roots extended in a large area and many adventitious buds, and the adventitious bud became a new plant in late. Rhizomatous rooted alfalfa are used to establish grass lands both for grazing and mowing, which has a relatively low root crown. The low root crown generated a stem similar to a root and the stem became a vegetative branch in late. Review paper of the past year in retrospect, a great number of studies have been focused on collecting forage resource, introduction, breeding, resistance evaluation, productivity evaluation, and genetic diversity of tap rooted and creeping rooted alfalfa at home and abroad. Mechanism, genetic characters and environment impact branch rooted of alfalfa were studied, but only a few studies have been focused on the contrast of different root types. Therefore, the ability of different root-type alfalfa to development root systems were studied for three years in semi-humid regions of Tianshui, semi-arid regions of Lanzhou and arid regions of Wuwei in Gansu Province to analyze their adaptabilities. The results showed rhizomatous rooted Medicago sativa cv. Qingshui was found with the shortest tap root length, the thinnest diameter of tap root and lateral root, the fewest lateral root numbers; creeping rooted native M. falcata material and M. varia cv. Gannong No.2 were found with longer tap root length, relatively diameter of thicker tap root and lateral root, more lateral root numbers; the indexes of tap rooted M. sativa cv. Longdong were found between rhizomatous rooted alfalfa and creeping rooted alfalfa, and was much closer with creeping rooted alfalfa. Diameters of tap root and lateral root were found grew faster of higher temperature in summer and autumn seasons. The volume and biomass of different root-type alfalfa decreased from tap soil to deep soil and increased with the age growth. Based on the integrated performance, rhizomatous rooted alfalfa was suitable for planting on semi-humid regions of Tianshui due to its root system development ability, creeping rooted alfalfa had the greater root system development ability in semi-arid regions of Lanzhou and arid regions of Wuwei, tap rooted alfalfa had the greater root system development ability in semi-humid regions of Tianshui and semi-arid regions of Lanzhou.

Vertical root distribution characteristics of Amorpha fruticosa on southern Mu Us Sandy Land

DU Ming-xin, ZHOU Xiang-rui, ZHOU Zhi-yu, LU Xin, LIANG Kun-lun, ZHOU Yuan-yuan, TAO Xiao-hui

2014, 23(2):  125-132.  DOI: 10.11686/cyxb20140215

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60-year, 35-year, 28-year and 6-year old Amorpha fruticosa growing on southern Mu Us Sandy Land were sampled using the total strain mining method. Aboveground morphological characteristics, soil moisture, root biomass, specific root length, root fraction, root volume, root surface area and root length density were studied to reveal the ecological adaptability of A. fruticosa in a sandy habitat. Results indicated that with increasing soil depth, the root biomass, root volume and root surface area of A. fruticosa of all ages declined exponentially in the form Y=ae^-bx. Root extinction coefficient analysis showed that roots were concentrated close to the soil surface. Parameters of root distribution showed different degrees of correlation: Soil moisture was significantly correlated with above ground biomass, root biomass, and specific root length. Soil moisture was also positively related to root surface area. The root distribution parameters, moisture control factor and framework factor, were confirmed by principal component analysis. With increasing years, A. fruticosa did not show an aging phenomenon since its roots had the ability to self-thin and update constantly, adapting to the changes in the environment.

Effects of eugenol and intercropped faba-bean on wheat root growth under different water supply conditions

ZHAO Cai, ZHOU Hai-yan, CHAI Qiang, HUANG Gao-bao, LIU Hui-juan, ZHU Jing

2014, 23(2):  133-139.  DOI: 10.11686/cyxb20140216

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The allelopathic effect of root exudates is quite common in soil and other media, and the effect due to the stress of continuous cropping often affects the root growth and yield of companion crops. This experiment, conducted under controlled environments, was to investigate the eugenol and intercropping effects on the root growth characteristics and yield of wheat (Triticum aestivum) under three water (75%, 60% and 45% of field capacity) supply conditions. Eugenol (2-methoxy-3-propenylphenol) exudates from wheat roots were used as the trial allelochemical. Results showed that eugenol at the rate of 300×10^-6 mol/kg of soil negatively affected root volume, root dry weight and root length of wheat crops. The negative effect of eugenol on wheat roots enhanced with a decrease of irrigation rate. There were significant differences between the 75% and 45% water supply levels. The negative effect on root volume, root length and root dry weight of intercropping wheat at 75% water supply conditions were lower by 54.69%, 26.70%, and 18.67% respectively than at 45% water supply conditions, and lower by 33.32%,49.55%, and 55.41% respectively in a monocropping system. In contrast, the wheat/soyabean intercropping system significantly weakened the allelopathic effect with little negative effect on root growth characteristics of wheat under the same water supply conditions. Cropping systems and water supply significantly affected root dry weight which then had a significantly positive impact on grain yield of wheat. This study demonstrates that the negative allelopathic effect, often occurring with continuous cropping, can be weakened through optimizing cropping systems and improved water management.

Effects of straw returning and nitrogen fertilizer application on root secretion and nitrogen utilization of rice

XU Guo-wei, LI Shuai, ZHAO Yong-fang, CHEN Ming-can, LI You-jun

2014, 23(2):  140-146.  DOI: 10.11686/cyxb20140217

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More than half of the straw has been burnt or discarded for years in China, which is not only a waste of organic fertilizer but also pollutes the environment. Meanwhile, heavy use of nitrogen fertilizer has become a serious problem in rice production. The practice of returning straw to fields and of using nitrogen fertilizer has important significance for the utilization of resources to reduce environmental pollution. This study investigated the characteristics of root secretion and its relationship to nutrient absorption and utilization in different straw and nitrogen treatments. A mid-season japonica rice cultivar (Xudao 6) was used as test plant with three nitrogen levels (no nitrogen, normal nitrogen and high nitrogen) and straw treatments. N accumulation at grain filing and N recovery efficiency of NN treatment was significantly higher than that of the other treatments under the same straw conditions. Similar results were also observed in some other tested indexes, including malic, succinic, total organic acid, amino acid and root activity. Under the same nitrogen treatment, N accumulation and utilization under straw returned at grain filing was higher than that in the other treatments. Straw returning improved malic and succinic acid contents of tested rice cultivars, but decreased the citric acid content. Root activity, contents of total organic acid and amino acid were also improved under the straw returning treatment. The contents of total organic acid, malic, succinic and amino acid and root activity were significantly correlated with N accumulation at grain filing and N recovery efficiency. Possible reasons for the differences in fertilizer utilization and root secretion characteristics under different treatments are discussed.

The relationship of root traits with persistence and biomass in 10 alfalfa varieties

PENG Lan-qing, LI Xin-yong, QI Xiao, YUE Yan-hong, FAN Shu-gao, LI Shu-cheng, WANG Yan-rong

2014, 23(2):  147-153.  DOI: 10.11686/cyxb20140218

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Plant root characteristics and their persistence and performance are closely related, but there are few studies of this relationship between different varieties of alfalfa. This research evaluated the relationship of root characters with biomass and persistence of 10 alfalfa varieties. The tested varieties were planted in 2001 and have been grown for 10 years. The main measurements were done in 2011 and some related data were used from measurements from 2001. There were significant differences in root traits between the alfalfa cultivars (P＜0.05). Xinjiang Daye and Gongnong No.1 had stronger taproots and crowns and more lateral roots. The taproot and crown of Super 7, Jindera and Eureka were smaller and there were fewer lateral roots. The root characteristics of L33,Amierica Daye,SD-006,Gannong No.1 and Ranbule were moderate. In addition, significant correlations were found between root morphological index and persistence and biomass. The varieties which had stronger taproots and especially strong crowns, and more lateral roots had better persistence. Varieties which had stronger taproots and crowns had higher biomass. These results indicate that Xinjiang Daye and Gongnong No.1, which had strong roots and crowns with better biomass and longer persistence, are more suitable varieties to be widely planted in the Hexi corridor.

Effect of fermention on ethanol production from fresh sweet corn stalks

GAO Rui-fang, ZHANG Jian-guo

2014, 23(2):  154-159.  DOI: 10.11686/cyxb20140219

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Corn stalks are an important resource that is abundant and cheap for fuel ethanol production. This study took curtal fresh sweet corn stalk as raw material with, yeasts (J), lactic acid bacteria (R) and cellulase (E) as additives. The additive treatments were: control (no additive), J, JR (J+R), JE (J+E), JER (J+E+R), MJ (J addition after sterilizing) and MJER (JER addition after sterilizing). The treated materials were sealed, and fermented for 10, 20, 30 and 40 days to study the optimum fermentation time and additives for ethanol production. The contents of water soluble carbohydrates (WSC) in sweet corn stalk significantly decreased with prolonging of fermentation times and were lower in the J, JR and MJ treatments than in the control (P<0.05). Fermentation time and additives had no significant effect on cellulose and hemicellulose contents. The ethanol yield tended to decrease with fermentation time from 10 to 40 days and was the highest (17.89% DM) under the following conditions: sterilized stalk and adding yeasts, fermenting for 10 d.

Effects of salinity on accumulation and distribution mode of dry matter and soluble sugar of Jerusalem artichoke (Helianthus tuberosus)

LI Hui, KANG Jian, ZHAO Geng-mao, YIN Xiao-ming, LIANG Ming-xiang

2014, 23(2):  160-170.  DOI: 10.11686/cyxb20140220

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There are many saline lands in China which can be ameliorated by planting salt-tolerant plant species, but salt stress has great adverse effects on the growth of plants. Due to its abiotic and biotic tolerance, Jerusalem artichoke (Helianthus tuberosus) has become increasingly considered for this purpose. In this study, two Jerusalem artichoke varieties (Nanyu No.1 and Qinyu No.2) were used in time course, soil pot experiments designed to study the effects of salinity on accumulation and distribution mode of dry matter and soluble sugar. Salt stress changed the dry matter distribution between shoots and tubers with more distribution in shoots but less in tubers. Nanyu No.1 had higher dry matter accumulation rates than Qingyu No.2 under salt stress, which reduced tuber dry weight per plant of Nanyu No.1 and Qingyu No.2 by 57.78% and 85.61%, respectively. The total soluble sugar contents of tubers and stems were reduced under salt treatments, but the total soluble contents of Nanyu No.1 were greater than those of Qingyu No.2. Reducing sugar content of stems of the two varieties were depressed significantly for Nanyu No.1 (77.34%) and Qingyu No.2 (60.79%), but the non-reducing sugar contents of both varieties were augmented. During the period of tuber initiation (100-140 days after planting), contents of tuber fructan were increased under salt stress, but decreased during the period of tuber filling (140-220 days). Under stress, Nanyu No.1 had higher tuber fructan accumulation contents or rate than Qingyu No.2. Contents of fructan accumulation were decreased by 74.02% and 93.81%, individually, and the rates of fructan accumulation were reduced by 77.08% and 98.44%, respectively. Our results demonstrate that salt stress greatly reduces the biomass of the two Jerusalem artichoke cultivars, changes the sugar distribution pattern, and delays fructan accumulation in the plants. Our study found that yield and fructan contents of Nanyun No.1 were less affected compared with Qingyu No.2, which implies Nanyu No.1 maybe better adapted to saline land.

Phytoremediation of Cd polluted saline soils by the halophyte Suaeda salsa

CHEN Lei, YANG Ya-zhou, ZHENG Qing-song, ZHANG Chun-yin, WANG Shuang, XU Cai-yun, GE Ying

2014, 23(2):  171-179.  DOI: 10.11686/cyxb20140221

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A pot experiment was conducted to investigate the growth responses to Cd and Na accumulation by Suaeda salsa under treatments of Cd (0-5.0 mg/kg) and NaCl (0.1%-1.0%). In soils containing 0.5% or 1.0% NaCl, the growth of S. salsa was significantly inhibited. Plant biomass decreased with an increase of soil Cd, while Cd accumulation increased with an increase of NaCl content. In the roots, stems and leaves of S. salsa, the highest Cd concentrations were (35.3, 30.1 and 30.9 mg/kg, respectively) in the 0.1% NaCl and 2.5 mg/kg Cd treatments. The bio-concentration factors of Cd in the shoots were 0.9-19.9, and the Cd accumulation in shoots was 8.1-73.6 times that of the roots. Fresh weight, Cd and Na concentrations in the roots of S. salsa were significantly affected by NaCl and Cd interaction, however the interaction was not significant for the Cd and Na concentrations in the stems and leaves. In the presence of Cd, Na contents in the stems and leaves increased as the NaCl content increased, but with the same Na addition, Cd did not lead to significantly different Na contents compared with the control. On the contrary, NaCl enhanced the accumulation of Cd in S. salsa. Sodium accumulation of S. salsa was only affected by the NaCl treatments. These results showed that S. salsa was Cd-tolerant and may strongly accumulate Cd, making it suitable for the phytoremediation of Cd-contaminated saline soils.

Physiological responses of Pennisetum longissimum var. intermedium seedlings to PEG, low temperature and salt stress treatments

ZHANG Huai-shan, ZHAO Gui-qi, LI Meng-fei, XIA Zeng-run, WANG Chun-mei

2014, 23(2):  180-188.  DOI: 10.11686/cyxb20140222

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The physiological characteristics of Pennisetum longissimum var. intermedium seedlings under three treatments of PEG-6000, low temperature and salt stress were studied using simulation adversity stress methods. The resistance and ecological adaptability were analyzed and comprehensively evaluated: 1) With increased concentrations of PEG the soluble proteins content initially increased but then decreased before increasing again. Soluble sugar initially increased but then decreased and had a maximal value when PEG was 5%. The content of MDA sharply increased at first, then remained stable and finally decreased significantly after a maximal value when PEG was 5%. The activity of SOD sharply decreased at first, then increased slowly then increased significantly. It had a minimal value when PEG was 5% and a maximal value with 20% PEG. 2) The contents of soluble protein and soluble sugar and the activity of SOD increased at first but then decreased with low temperature stress. The content of proline increased with increasing temperatures and MDA also showed an increasing trend. 3) With increased concentrations of salt, the soluble protein content initially increased but then decreased while the contents of soluble sugar, proline and MDA increased. SOD activity showed a slight increase at first, then slowly reduced followed by a rapid decline. Correlation analysis showed that the content of proline was significantly negatively correlated with soluble sugar concentration under PEG treatment. With low temperature stress of 4 hours, the contents of MDA were significantly positively correlated with soluble sugar and proline. With NaCl treatment, the content of soluble sugar was significantly positively correlated with MDA and proline, the activity of SOD was significantly negatively correlated with soluble sugar and MDA while it was significantly positively correlated with soluble protein. To sum up, the physiological dynamic changes of P. longissimum var. intermedium in its response to inverse factor stress reflects its adaptive response of resistance to adversity stresses and reducing injury.

Effects of applying exogenous plant hormone on praline metabolism of Swainsonia salsula seedlings under NaCl stress

WANG Ruo-meng, DONG Kuan-hu, LI Yu-ying, LI Chen, YANG Jing-fang

2014, 23(2):  189-195.  DOI: 10.11686/cyxb20140223

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Swainsonia salsula seedlings were treated with cytokinin (6-BA) and abscisic acid (ABA) then subjected to eight salt treatments (0, 80, 160, 240, 320, 400, 480, 560 mmol/L of NaCl). Proline metabolism enzymes, root top ratio of leaves and roots of S. salsula were analyzed to study the effects of exogenous plant hormone on salinity tolerance after two weeks to provide a theoretical basis for cultivation of salt-tolerant forage. Exogenous plant hormone improved salinity to lerance of S. salsula. Under exogenous plant hormone treatment, roots were more sensitive to hormone treatment than leaves and the effect of 6-BA was more significant than that of ABA. After exposure to exogenous plant hormone, other indexes of stress resistance were reduced except Pro in S. salsula.

Red light induced SGT3 gene expression and functional analysis of the SGT3 promoter in potato

CUI Tong-xia, BAI Jiang-ping, WEI Gui-ming, ZHAO Xu, WANG Di, ZHANG Jin-wen

2014, 23(2):  196-206.  DOI: 10.11686/cyxb20140224

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Rhamnosyltransferase (SGT3) is a key enzyme involved in synthesis of plant glycoalkaloids, and mainly catalyzes the transformation of α-solanine and α-chaconine from their β-form. We studied the SGT3 gene expression and its promoter function in potato cultivars (Solanum tuberosum), and found that after 24 hours red light treatment, the transcriptional expression of SGT3 was increased 26.8 fold compared with control (under dark). The data thus suggested that red light induced the expression of SGT3. To further understand the regulation mechanism of SGT3, the putative SGT3 promoter region (2449 bp upstream of the open reading frame) was cloned and the sequence was analyzed to predict the cis-elements including promoter core sequences, enhancer sequences, inhibiting sequences, pathogen- responsive element, drought- and ABA- responsive element, and a few light-regulated elements. The transcription start site of the promoter is located 152 bp upstream of the translation start site. To study the function of the SGT3 promoter, the GUS expression vector driven by SGT3 or CMV 35S promoter were constructed and transformed to tobacco leaves to analyze the transient expression and stable expression. The results demonstrated that the SGT3 promoter can drive the expression of GUS, but the expression level was less than that driven by the CMV 35S promoter. The highest GUS expression was detected in tobacco leaves transformed by P572 and P979 but the GUS expression was decreased with P1312 and P1870. More positive regulatory elements were observed within 1000 bp upstream of the start code. The tissue specificity analysis indicated that the SGT3 driven GUS expression was mainly concentrated in the veins of the tobacco leaves, but was not detected in mesophyll cells. In the root, GUS was detected in meristem and vascular tissues. In the stem, GUS was detected in epidermis, xylem and phloem of tobacco stems.

Cloning and expression of PtGAPDH from Puccinellia tenuiflora

ZHANG Yang, GUO Hai-jun, LIU Long-biao, WANG Sa, LIANG Ying, NIE Yu-zhe, LI Yu-hua

2014, 23(2):  207-214.  DOI: 10.11686/cyxb20140225

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A full length cDNA named PtGAPDH related to saline-alkali tolerance was cloned from Puccinellia tenuiflora by RT-PCR and RACE (rapid amplification of cDNA ends). PtGAPDH gene with 1014 bp open reading frame encoded a protein with a predicted length of 337 amino acids. Phylogenetic analysis indicates that this gene, denoted PtGAPDH, has sequence characteristics similar to other monocotyledon GAPDH genes. Northern blot shows the expression of PtGAPDH has increased with the growth of the concentration of Na₂CO₃ in the proper realm, otherwise, has decreased both in leaves and roots. The expression pattern of PtGAPDH gene stands for the regular effects of the saline-alkali stress on the gene expression of P. tenuiflora on the molecular standard.

Construction of an EMS induced mutant library and identification of morphological characteristics in Medicago sativa

XIA Zeng-run, DU Feng-feng, LI Si, ZHANG Ji-yu, LIU Yong, HUO Ya-xin, KONG Lin-fang

2014, 23(2):  215-222.  DOI: 10.11686/cyxb20140226

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The effects of different concentrations of EMS on seed germination and seedling growth in Medicago sativa were analysed and the morphological characters of M₁ mutants identified. The final germination rate, germination index and the length of radicle and germ of M₁ seeds were restrained after EMS treatment. There were 379 mutants from 1039 M₁ populations showing leaf (but excluding leaf shape and quantity), plant height, branch number, plant type mutations. The mutant lines of leaf color, branch number, plant type and others were 215, 40, 95 and 28 respectively and the frequency was 20.69%, 3.85%, 9.14% and 2.69%. The mutant library we constructed will be a very useful genetic resource for functional genomics and genetic improvement of M. sativa.

Morphological study of the leaf structures of Viola in northeastern China and discussions of their taxonomic values (Violaceae)

SUN Xue-qin, LIU Mei, SUN Tian-hang, ZHANG Xing-xing, SHI Chuan-qi

2014, 23(2):  223-234.  DOI: 10.11686/cyxb20140227

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The leaf structures of 28 species and 1 variety of Viola in northeastern China were studied in this paper using GMA method and peeling leaf epidermis method. The results show the leaf shapes of the genus are cordate, reniform, oval and long triangle. Stipules are usually lanceolate. Nonglandular hairs may be unicellular or two-celled. Stomata are mainly anisocytic type. Petioles are mostly semicircle with two wings in transverse sections. Vascular bundles are three which are arranged in U-shaped or reniform. Aerenchyma and fibers are present in some species. The leaf shapes and structures differ in different species, but are similar in different Sect., and they can provide the morphological evidences for the classification of species and groups. This study also support the estimation of Subgen. Chamaemelanium, Subgen. Melanium and Sect. Viola, incorporating Sect. Pinnatae into Sect. Adnatae and Viola prionantha, V. phalacrocarpa and V. yedoensis as three independent species. Our study provid the basic data for further and deeply study of Viola of Chinese and Violaceae.

Comparative study of the morphological and anatomical features of Lindernia procumbens in different ecological environments (Linderniaceae)

ZHANG Xin-xin, LIU Mei, CHENG Xin-yu, SHI Chuan-qi, RU Jian, SUN Yan

2014, 23(2):  235-242.  DOI: 10.11686/cyxb20140228

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The morphology and anatomy of Lindernia procumbens were deeply studied using the GMA method for the first time. The results show the seedling development of the species has the characteristics of aquatic plants: the seed and seedling submerged in water could germinate and develop, the hypocotyl hairs occur on the collet, the radicle development is retardate. The vegetative organ of the mature plant of the species has the characteristics which occur in terrestrial plants and aquatic: the terrestrial plant and aerial parts of the hygrophilous plant have thick cuticule, developed mechanical tissues and aerenchymaes. However, the submerged plants and submerged parts of hygrophilous plants are with the undeveloped mechanical tissues and cuticule, very developed aerenchymaes. The reproductive organs: L. procumbens has two types of flowers, chasmogamous and cleistogamous. Both occur in the terrestrial and the hygrophilous plants, but the submerged plants only have cleistogamous flowers, which make the species could produce seeds normally. In addition, the species has a free central placenta. This study show the variation in shapes and structures (including seeding development, vegetative and reproductive organs of L. procumbens) in the different ecological environments for the first time, perfecting the morphological study and providing the morphological evidence for the systematic study of the family Linderniaceae.

Study on a laccase-producing fungus from alpine grassland soil in eastern Qilian Mountains: screening, identification, and activity analyses

LU Guang-xin, WANG Jun-bang, CHEN Xiu-rong, YANG Cheng-de, XUE Li

2014, 23(2):  243-252.  DOI: 10.11686/cyxb20140229

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The sixty-five fungi strains that were isolated from the alpine grassland soil in the eastern Qilian Mountains were researched as the object in this paper. The fungi initially selected through culturing on the medium of guaiacol-PDA and α-naphthol-PDA medium. The fungi with the function to produce laccases was screened (identified as No. 310b) based on the growth and colony sizes on the culture mediums of guaiacol, caechol, and o-benzyl aniline, the activities of redox reaction catalyzed by the laccases in these fungi grown, as well as the activity of laccases in these fungi cultured on the stems of oil rape. By rDNA-ITS sequence analysis, the fungus was identified as Marasmius tricolor. Then elementary study on the conditions under which laccases were produced by the fungus (No. 310b) was carried out. These results showed that the activity of laccases in the fungus reached the peak when it was cultured under the condition: 25℃, initial pH 4.0, sucrose and peptone that were used as carbon and nitrogen resources, respectively. Few non-trophic organic chemicals showed different effects on laccase activity in the fungus. α-naphthol and Tween-80 did not have significant effects on laccase activity in the fungus, but guaiacol, tannic acid, and indole acetic acid inhibited the activity of laccases, especiall indole acetic acid, which significantly inhibited laccase activity (P＜0.01). When Cu²⁺ concentrations ranged from 0.001-0.025 g/L, laccase activity increased as the concentrations of Cu²⁺ increased, reaching the peak at 0.025 g/L. With the increase of inoculum sizes, laccase activity increased. Ranging from 60 to 180 r/min, laccase activity increased. When the amount of the powder of oil rape stems ranged from 0 to 1 g, laccase activity increased, but when the amount was higher than 1, the activity decreased.

Screening and degradation characterization of efficient and stable cellulose degrading microbial communities

WANG De-wu, YAO Tuo, YANG Qiao-li, HAN Hua-wen, ZHANG Ying, LU Hu, GUN Shuang-bao

2014, 23(2):  253-259.  DOI: 10.11686/cyxb20140230

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A range of materials (primeval forest humus, rotten corn straw, soil samples near by cattle farm trough, bottom of wheat-rick, cattle and chicken feces compost) were screened on restrictive media at room temperature to obtain efficient, cellulose degrading, microbial communities. The capability for degradation and decomposition of fibrous materials at different initial pH conditions were analyzed using a weight loss method. The composition and characterization of this microbial system was identified using a solid plate culture method. The cellulose microbial communities screened from cattle and chicken faeces compost were better than those from other materials for decomposition of cellulose. They could decompose filter paper into a paste after 48 hours culture, and filter paper, corn straw, rice straw, wheat straw, xylosma and poplar wood chips were degraded by 94.95％, 48.52％, 45.05％, 44.30％, 11.00％ and 1.22％ respectively after 6 days continues cultivation. With an initial pH of 4 to 10 of the zymotic fluid reaction system, cellulose microbial communities could degraded 84.59% of the filter paper, and the pH finally stabilized in the range of 8.5-8.8. Eight fungal strains, 6 bacterial strains and 3 actinomycete strains were isolated and purified from this cellulose microbial community. these strains were incubated into each other artificially, but could not degrade cellulose. The results of this study indicate that cellulose microbial communities had strong capability to degrade cellulose and straw class lignocellulose.

Effects of fructo-oligosaccharides on mucosal morphology, digestive enzyme activity, organic acid and Lactobacillus of the gastrointestinal tract of unweaned piglets

HANG Su-qin, SHI Qi, DING Li-ren, ZHU Wei-yun

2014, 23(2):  260-267.  DOI: 10.11686/cyxb20140231

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Six litters (8-11 piglets per litter) of healthy neonatal crossed-bred piglets (Duroc×Landrace×Yorkshire) were randomly divided into a control group and treatment group. Each group was composed of three litters, comprising triplicates. The animals in the control group were offered regular starter feed, while those in the treatment group were fed starter feed with 1% replacement of fructo-oligosaccharides (FOS) (by dry matter %) at 7 days after birth. The experiment was ended 23 days (weaning) after birth. At 7 and 23 days, one piglet from each triplicate was slaughtered. Pancreas, gastrointestinal tract (GIT) tissues and digesta were collected to investigate effects of FOS on mucosal morphology, digestive enzyme activity, organic acid and Lactobacillus of the GIT of unweaned piglets. The results showed that the villi height and the ratio of villus height and crypt depth were increased by FOS treatment in the jejunal and ileum (P<0.05). The highest amylase activity was in the pancreas and duodenum of the FOS group (P<0.05). Lipase and protease activity were not significantly higher in the FOS group than in the control group (P>0.05). Higher VFAs (volatile fatty acids) concentrations in the GIT and lower lactic acid concentrations in the stomach were observed in the FOS treatment (P<0.05). The number, similarity and diversity of Lactobacillus communities were also increased by FOS supplementation. The findings imply that the small intestinal morphological development of unweaned piglets, the activities of digestive enzymes, and VFAs concentration in gastrointestinal contents were improved by FOS addition. FOS can be utilized by some species of Lactobacillus, which enhances the stability of microbial community structure in the GIT of unweaned piglets, resulting in a beneficial contribution to the enteric health of piglets and a possible smooth transition at weaning.

Ruminal degradability characteristics of different forages in sheep

CHEN Xiao-lin, LIU Zhi-ke,SUN Juan, WANG Yue-chao, LI Yan-ling, JIANG Cheng-gang, TU Yan, DIAO Qi-yu

2014, 23(2):  268-276.  DOI: 10.11686/cyxb20140232

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In order to investigate dry matter (DM) and protein (CP) degradation rule of different forages, three Dorper×Han crossbred male sheep fitted with permanent rumen fistula were selected to estimate DM and CP ruminal degradability of 13 forages in situ. The results showed as follows: ruminal degradability at various time points of DM and CP of Medicago sativa were highest; Astragalus adsurgens, Setaria viridis, Arrhenatherum elatius and Poa pratensis were significantly higher than others at 72 hours (P<0.05). For 13 forages, potential degradation part and effective degradability of DM showed the similar change law with degradability at various time points of DM. CP effective degradability of leguminosae M. sativa and A. adsurgens were highest; gramineae A. elatius, Pennisetum purpureum, P. pratensis and S. viridis were significantly higher than others (P< 0.05). The rate constant for the slow degradation part of M. sativa was significantly higher than other forages (P<0.05). In conclusion, DM and CP ruminal degradability of leguminosae M. sativa and A. adsurgens were higher than gramineae pasture; gramineae A. elatius, P. pratensis, P. purpureum and S. viridis were higher than other 7 forages; Poa crymophila, Elymus sibiricus, Leymus chinensis and Elymus dahuricus were in the middle; Achnatherum splendens, Festuca sinensis and Phragmites australis were low.

Effects of diet nutritional on slaughter performances and meat quality of Yunnan semi-wool sheep

ZHAO Yan-guang, HONG Qiong-hua, XIE Ping, HU Qing-quan, LIU Shao-na, HONG rong, PENG De-lin

2014, 23(2):  277-286.  DOI: 10.11686/cyxb20140233

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Effects of diet supplement at different nutrition levels on slaughter performance and meat quality of Yunnan semi-wool sheep were investigated in this paper. Forty-eight Yunnan semi-wool sheep were evaluated in a one-factor randomized complete block design with 4 levels. Based on gender and feeding methods, animals were divided into four groups. In each group, 2 repeats with 6 (3♂+3♀) individuals were applied, and two individuals were slaughtered and evaluated at the end of experiment. Slaughter performance, carcass characteristic and meat quality were also improved. An optimized dietary formula was proposed for Yunnan semi-wool sheep. As for 15—25 kg sheep, concentrates with low nutrition level were appropriate for male ones, while concentrates with mediate nutrition level were suitable for female ones, and for 25-40 kg sheep, concentrates with high nutrition level were feasible.

Response of soil large- and mesofauna to edaphic characterization along vegetation second succession sequence of inland saline marsh

LUO Jin-ming, YIN Xiong-rui, YE Ya-jie, WANG Yong-jie

2014, 23(2):  287-295.  DOI: 10.11686/cyxb20140234

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The spatial distrubution patterns of soil large- and mesofauna along typical vegation second succession sequences of inland marsh were examined in a field experiment. Within the study plots,at 1500 m distance there was an obvious response to the soil sequence by the soil fauna. In reed marsh the highest individual density was 728 individuals/m² whereas it was a mere 8 individuals/m² in bareland. Nevertheless, the largest species density value and Shannon-Wiener index were in the surface horizon of chinese grassland, with 10 species/m² and 1.75 respectively, versus 4 species/m² and 0.91 in bareland. Dominant species in bareland and grassland were Coleoptera, Diptera and Collembola, but were Hymenoptera and Diptera larvae in grassland. and meadow, but Cyclphoridae and Diptera larvae in reed marsh. A canonical correspondence analysis was applied to examine the response of soil fauna to soil properties of typical vegetation second succession sequences. Two types of environmental factors affecting soil fauna species living patterns were found: high moisture and humus content resulted in a richness of individual density and diversity of soil microfauna. The other factor is salinity, and exchangeable sodium percentage in particular, which restrain the activity of soil microfauna. Protection and restoration vegetation in inland saline marsh regions would help wetland conservation and soil fauna biodiversity.

Monthly changes of ground arthropods in artificial Caragana intermedia plantations in desert steppe

LIU Ren-tao, ZHU Fan

2014, 23(2):  296-304.  DOI: 10.11686/cyxb20140235

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Taking 6, 15, 24, 36 year old artificial Caragana intermedia plantations in desert steppe as a subject, an investigation on ground arthropods from May to September was carried out using pitfall traps. The monthly changes of ground arthropod are discussed, together with their relationship to the stand age. 1) There were seventy-two groups captured and they belonged to 62 families, 13 orders and five classes. In light of the guilds, there were six functional groups: predator, phytophagous, saprophagous, coprophagous, omnivorous and parasitic animals. Carabidae, Tenebrionidae and Melolonthidae dominated the ground-arthropod community and comprised 46.71% of total individuals. 2) From May to June, such dominant groups as saprophagous animals were as abundant as phytophagous and omnivorous and parasitic animals in each shrubland. In July in 36-year-old shrubland, predator animals increased, while from August to September in each shrubland, they were the dominant groups. With increasing stand age, the food web tended to become more complicated in ground arthropod communities. 3) The peak of dominant groups in 6-year-old shrubland was in September, in 15-year-old shrubland it was in June and September, in 24-year-old shrubland it was in June, August and September, and in 36-year-old shrubland it was in June, July, August and September. With increasing stand age, the monthly distribution of dominant groups tended to be homogeneous in ground arthropod communities. 4) The maximum density in 6-year-old shrubland was in May and September, and the minimum was in August; From 15 to 24-year-old shrubland, the maximum density was in May with relatively low number of individuals in the other months; In 36-year-old shrubland, August followed May in maximum density. Stand age effects were maximum in August but minimum in May, June and July. 5) It is suggested that monthly changes of ground arthropods were strongly affected by stand age, which had direct influences on the structure and function of grassland ecosystems and related recovery processes.

Effects of zokor-mound succession on plant functional group and productivity

ZHANG Ling-fei, ZHANG Xin-zhong, ZHANG Yan-kun, YE Na-na, FU Hua, JIANG Xiao-lei

2014, 23(2):  305-312.  DOI: 10.11686/cyxb20140236

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Using a spatial sequence instead of a temporal sequence approach,the species diversity and productivity of different plant functional groups, including life form groups and palatability groups, were investigated along a successional gradients of zokor-mond in alpine meadows on the Qinghai-Tibetan Plateau. Plant functional groups of both life forms and palatability, as well as productivity were strongly affected by the succession on zokor-mounds. For life form groups, with an increase of successional gradients, the diversity of annuals significantly decreased, perennial grasses significantly increased, while sedges and perennial forbs showed a unimodal tendency. The situation of successional effects on productivity for life forms was similar to that of species diversity. For palatability groups, the diversity of poisonous and fine species peaked in the intermediate stage, while the diversity of inferior, medium and excellent species increased considerably along the successional gradients. The peak productivity of poisonous and fine species was also manifested during the intermediate stage. The productivity of inferior species decreased significantly, while that of medium and excellent species increased dramatically along the successional gradients. These results indicate that the succession on zokor-mounds benefits both the plant functional group diversity and grassland productivity.

Advance in shrub encroachment in arid and semiarid region

PENG Hai-ying, LI Xiao-yan, TONG Shao-yu

2014, 23(2):  313-322.  DOI: 10.11686/cyxb20140237

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Shrub encroachment is the increase in density, cover and biomass of indigenous woody or shrubby plants in arid and semiarid grasslands, which become a great ecological problem in arid and semiarid region. It is one of the most important parts of research in the global change of terrestrial ecosystem. Shrub encroachment was resulted from the interactions of many factors including over grazing, fire, climate change, elevated atmospheric CO₂, changes about biotic and abiotic environment factors. Shrub encroachment could occurred a suddenly vegetation shift from a stable stage with grasses dominant to a stable stage with shrub dominant, with a great change in the composition and structure of plant community. The whole landscape fragmentation and heterogeneity increased in the processes of shrub encroachment. The light, heat, water and nutrients in ecosystem were redistributed with the establishment and development of shrub seedlings. Shrub patches gradually formed “fertile islands” with water and nutrients enrichment. The current studies about shrub encroachment were mainly concentrated on fixed-point research and factor controlled experiments with distinct locality and restrictions. We should pay more attention on the relationship of climate change and shrub encroachment, feedback of grassland ecosystem for shrub encroachment and research about strategies and countermeasures relative to shrub encroachment, model simulation might be one of important ways to study the occurrence and development of shrub encroachment even to predict the succession of ecosystem.

Effects of nitrogen deposition on critical fractions of soil organic carbon in terrestrial ecosystems

CAO Cong-cong, QI Yu-chun, DONG Yun-she, PENG Qin, LIU Xin-chao, SUN Liang-jie, JIA Jun-qiang, GUO Shu-fang, YAN Zhong-qing

2014, 23(2):  323-332.  DOI: 10.11686/cyxb20140238

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Soil organic carbon can provide the nutrient for plant growth and maintain soil physical structure well, and soil organic carbon (C) pool is so large to lead to big changes in CO₂ concentration in atmosphere even its changes are small, thus soil organic C pool has a direct effect on the global C balance. Nitrogen (N) is recognized as the primary limiting nutrient for plant growth in terrestrial ecosystems. Atmospheric N deposition and anthropogenic N input are important N sources to terrestrial ecosystems, whose alteration will profoundly change plant growth and net primary production in terrestrial ecosystems, accordingly impacts global C cycles and other ecosystem processes. Ecological scholars in European countries and the United States have carried on a series of extensive and in-depth studies on the effects of N input on various types of ecosystem C pools during the past 20 years. Chinese scholars, in recent years, also turned their attention to the study of N input’s impacts on the terrestrial C cycle processes, and have made a lot of research advances. Nevertheless, the effect of N deposition and anthropogenic N input and its intensity on C cycles are still a weakest part among the studies on the four main C sink mechanisms. In view of this, this article reviews and analyses the influences of atmospheric N deposition on the total organic C (TOC), dissolved organic C (DOC) and microbial biomass C (MBC) in the soil pool of terrestrial ecosystem, and puts forward some prospects on the problems existed in present researches, which had the potential to be a reference for the further study carried out in the future in China.

Tolerance of alpine meadows to human trampling

HUANG Xiao-xia, ZHANG Yong, HE Ke-jian, DING Jiao, ZHAO Wen-juan

2014, 23(2):  333-339.  DOI: 10.11686/cyxb20140239

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To quantify the relationship between trampling and vegetation damage, field simulations with standardized methodology were conducted to determine the resistance and resilience of alpine meadow in Shangri-La for two communities: dry meadow and mesophytic meadow. Vegetation parameters were measured in lanes subject to control (no trampling), 50, 100, 200, 500 and 700 passes at six sites prior to trampling, immediately after trampling, 2 weeks and 1 year after trampling. Relative vegetation cover (RVC) was calculated for each trampling treatment. RVC comparisons for each path and community were done by Analysis of Variance (ANOVA), and regression models were used to calculate the coefficient of resistance. 1) RVC decreased with increasing trampling intensity, although the curves of interpolated RVC values for all possible trampling intensities between 0 and 700 were similar, while the mean RVC was significantly different only at the 700 passes. 2) The resistance indices (number of passes resulting in 50% reduction in RVC) were around 708 passes for the dry meadow and around 551 passes for the mesophytic meadow, indicating these two communities were high resistance vegetation types as compared with other mountain meadow communities tested around the world. 3) One year after trampling, the RVC recovered 66.5% in dry meadow and 86.1% in mesophytic meadow, suggesting that the latter showed stronger resilience than the former. 4) Resistance of the main species were around 390-578 passes for the dry meadow and 282-463 passes for the mesophytic meadow, showing the resistance of different component species varied greatly under different environmental conditions. This study demonstrates that high elevation vegetation communities vary in their resistance and resilience to disturbance. Results such as those obtained here can underpin management decisions, and support long term monitoring programs of trampling impacts.

Stoichiometry characteristics of plant and soil in alfalfa grassland with different growing years

YANG Jing, XIE Ying-zhong, WU Xu-dong, XU Kun

2014, 23(2):  340-345.  DOI: 10.11686/cyxb20140240

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Through measuring and analyzing carbon (C), nitrogen (N), phosphorus (P), and its stoichiometry ratios of leaf, stem and 0-20 cm soil under different plant ages (1, 3, 4, 5 to 8 years) of alfalfa at the foot of Helan Mountain in Ningxia, the influence of planting-age on nutrient content and stoichiometry of soil and plant in alfalfa grassland were researched. 1)With the increase of plant time, 0-20 cm soil C and N firstly increase and then descend, but the P is contrary. There were significant differences between different planting-age (P<0.05). 2)The C in leaf decreased and P in leaf decreased after increase with the increasing of plant time. Each of stem nutrient content change as well as soil nutrient content, but the amplitude of variation is less than leaf nutrient content. 3) The N/P and C/P in leaf showed a negative correlation with P in leaf, but showed no correlation with N in leaf. There were a certain correlation between P in soil and C, N, P and its stoichiometry in stem.

Effects of super absorbent polymer application rate on soil nitrogen of spring-sown naked oat in two irrigation systems

WU Na, HU Yue-gao, REN Chang-zhong, LIU Ji-li

2014, 23(2):  346-351.  DOI: 10.11686/cyxb20140241

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The present study, was a split plot field experiment to investigate the variation of soil nitrogen of spring-sown naked oat (Avena nuda) under two irrigation systems (traditional irrigation and drip irrigation) and four levels of super absorbent polymer (0, 30, 60 and 90 kg/ha). With an increase of the amount of super absorbent polymer, the content of soil total nitrogen, soil nitrate nitrogen and ammonium nitrogen initially increased but then decreased. The contents of soil total nitrogen, soil nitrate nitrogen and ammonium nitrogen reached their highest levels when SAP application was 60 kg/ha, and the contents under drip irrigation were higher than under traditional irrigation with the same levels of super absorbent polymer. Traditional irrigation caused soil nitrate to leach down, but was not conducive to absorption of nitrogen while an appropriate irrigation quota of drip irrigation (spring-sown was 140 mm) was beneficial for increasing soil tilth nitrogen.

Fruit-set patterns and burial mechanism for subterranean dispersal units of Ceratocarpus arenarius

WANG Xi-yong, GAO Rui, ZHOU Xiao-qing, WEI Yan

2014, 23(2):  352-357.  DOI: 10.11686/cyxb20140242

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Ceratocarpus arenarius is an annual desert plant in the Junggar Basin, Xinjiang. It produces two clearly different types of fruits in aboveground and subterranean on the same plant. The main aims of this study was to investigate the phenology, fruit-set patterns and burial mechanism of the subterranean dispersal units of this species. Life history of C. arenarius is eight month. It has long cotyledon period, there are about 30 days. Blossoming and fruiting soon, and it has a long reproductive period, which accounts for 4/5 of the whole lifecycle. The subterranean dispersal units originate from two female flowers in the binate axils of the first node of the main stem. At the last ten-days of April, the two female flowers are pollinated on the ground; after bracts entirely concrete, the two subterranean fruits develop into underground in the middle ten days of June. The flowers of the subterranean dispersal units of C. arenarius have specificity due to it include only two flowers which are on the first node of the main stem. However, a number of aerial dispersal units on the leaf axil which forms a spherical shape. The subterranean dispersal units bury by both combinative dynamic of the “reversing” mode and passive mode by means of soil and sand brought by wind and rain. This fruiting traits are the adaptative strategies of C. arenarius to the unpredictable desert.