Table of Content

20 August 2012, Volume 21 Issue 4

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Research on the dynamic changes of soil properties of typical steppe in the restoring process

SHAN Gui-lian, CHU Xiao-hui, TIAN Qing-song, MA Yu-bao, LI Ling-hang, CHEN Gong

2012, 21(4):  1-9. 

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Soil properties of typical steppe response to restoring succession progress were measured in a grassland experiment site in Taipusi county of Inner Mongolia, China. The grasslands have been exclosed (April to September every year) for 7,10,13 and 20 years, respectively. Soil samples were collected in mid-August in 2008, and soil physical properties, chemical properties as well as biological properties were monitored. Results showed that the soil properties presented a series evolution tendency during grassland restoration succession process. Compared with continuous grazing areas, exclosing treatment over 7 to 20 years significantly decreased the soil bulk density in the layer of 0-30 cm (P＜0.05), and increased both silt-clay content and soil porosity (P＜0.05). In addition, exclosed grasslands had significantly higher soil organic matter, total nitrogen, total phosphorus, available nitrogen, available phosphorus, available potassium, microbe quality and microbial biomass than continuous grazing areas, especially in the layer of 0-10 cm. Soil structure and quality could be deteriorated again and recovered grassland would present the second retrogressive succession due to continuous hay cutting. Further studies are needed to investigate rational use of typical steppe during their restoring process.

A study on soil enzyme activity in four different grasslands of the eastern Tibetan Plateau

SUO Nan-ji, TAN Yan-rong, ZHU Wei-xin, GU Zhen-kuan, DU Guo-zhen

2012, 21(4):  10-15. 

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Four different types of grasslands (alpine meadow, alpine shrub, swamp meadow, mountain steppe) on the eastern Tibetan Plateau were analyzed for variation of soil physicochemical characteristics (soil moisture, pH, organic carbon, total nitrogen), soil enzyme activity (β-glucosidase, acid phosphatase, urease) and the inter-relationship among them. Soil enzyme activities in the upper soil layer (0-15 cm) were higher than those in the lower layer (15-30 cm), and the trend was consistent with the four types of grasslands, which indicated that soil biochemical reactions in the upper soil layer were stronger than those in the lower layer. Activities in the four different types of grasslands were in the order: Soil β-glucosidase - swamp meadow＞alpine shrub＞alpine meadow＞mountain steppe; acid phosphatase activities - swamp meadow＞alpine meadow＞alpine shrub＞mountain steppe; urease activities in the upper soil layer - swamp meadow＞alpine shrub＞mountain steppe＞alpine meadow, and in the lower soil layer - mountain steppe＞swap meadow＞alpine shrub＞alpine meadow. Soil enzyme activities in swamp meadow were generally higher than in the other three types of grasslands, which indicated that higher primary production in swamp meadow provides more carbon and nitrogen sources for the growth of microorganisms. Correlation analysis indicated that soil urease activity had a significant positive correlation with total nitrogen; soil β-glucosidase activity and acid phosphatase activity had a significant positive correlation with soil organic carbon and total nitrogen. They can therefore be used as indicators of soil fertility.

Effects of genotype, environment and their interaction on the main agronomic traits of Panicum miliaceum

LI Xin-cun, YANG Tian-yu, ZHANG En-he

2012, 21(4):  16-24. 

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In order to study genotype, environment and their interaction effect on main agronomic characters of Panicum miliaceum, the growth period, plant height, stem nodes, main spike length, spike grain weight, 1000-grain weight and yield 7 main characters, variety stability and adaptability were investigated with combined variance and AMMI model methods in 11 different environments pilot. The main agronomic characters of P. miliaceum between different genotype and environment existence were extremely remarkable difference. Genotype effect on main stems obviously, and environment on plant height, genotype and environment interaction on grain weight. All varieties of 7 agronomic traits of variation coefficient, the largest was production, up to 42.72%, followed by spike grain weight and plant height, respectively achieved 37.90% and 26.74%. The variation coefficient smallest was growth period, only to 14.89%. All test pilot, Gan 9133-1-3-4-1 yield was the highest, Yumi 3 (CK) variety stability was the highest of all. Ningxia Pengyang and Shanxi Yanan had higher yield, and variation degree was small, advantageous to variety discernment of varieties.

Research on reproductive allocation of biomass and nutrients in different phenological stages of Glycyrrhiza inflata

ZHOU Xiao-ling, MA Xin-e, SHANG Ke-wei, MA Chun-hui

2012, 21(4):  25-32. 

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The biomass, energy and nutrient (N, P, K) contents of different components (stems, leaves, flowers, pods) were measured at different phenological stages (budding, flowering, podding, and maturity stages) of Glycyrrhiza inflata in the extremely arid climate in Xinjiang to explore the dynamic changes of reproductive allocation in biomass, energy and nutrients in the phenological stages. 1) The reproductive allocation of G. inflata increased with the phenological stage. In budding, flowering, podding and maturity stages, reproductive allocation was 2.40%, 4.30%, 13.90%, and 18.90%, respectively. 2) The phenotype plasticity of the reproductive module was higher than that of the vegetative module, and sexual reproduction decreased with progressive phenological stages. 3) Biomass of flowers (pods) had significant (P<0.05), positive and linear correlations with the leaf biomass, stem biomass or total biomass in the four phenological stages. 4) The energy and nutrient element allocation of different modules varied consistently with the biomass: the highest values in leaves were in the flowering stage, in stems were in the budding stage, and they increased with the phenological stages in reproductive modules. In conclusion, the sexual reproduction of G. inflate was an accumulative process of matter, energy, and nutrient elements, with a minor proportion used for sexual reproduction but the majority used for vegetative growth.

A study on the morphological diversity of 475 accessions of Cynodon dactylon

HUANG Chun-qiong, LIU Guo-dao, BAI Chang-jun, WANG Wen-qiang, TANG Jun, YU Dao-geng

2012, 21(4):  33-42. 

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The genetic diversity of C. dactylon accessions originating from different regions were assessed using morphological markers: morphological diversities of 475 accessions of Cynodon dactylon were studied using 17 morphological characters. 1) Abundant morphological variation existed in accessions of C. dactylon. The variations of turf height, leaf length, and internode length were the largest, followed by inflorescence length, leaf width, internode diameter, and spikelet number. Inflorescence branch numbers had the least variation. 2) There were significant correlations among some morphological characters of C. dactylon accessions. With increasing turf height, C. dactylon had longer leaves, stronger stolons, longer inflorescence lengths, more inflorescence branches and spikelets, and more hairs.3) The accessions clustered into two major morphological types using the unweighted pair-group method with arithmetic averages (UPGMA), designated as either high type or low type.

Salinity tolerance evaluation of Zoysia turfgrass germplasm

LI Shan, CHEN Jing-bo, GUO Hai-lin, ZONG Jun-qin, ZHANG Fang, CHU Xiao-qing, JIANG Qiao-feng, DING Wan-wen, LIU Jian-xiu

2012, 21(4):  43-51. 

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Salinity tolerance in 103 Zoysia accessions from seven species was assessed in hydroponic culture containing 20 g/L NaCl. The relative green leaf coverage and relative dry shoot clipping weight showed that there were differences in salinity tolerance between accessions. Using relative green leaf coverage as an indicator, there were 28 and 46 accessions with more salinity tolerance than ‘manilagrass’ and Zoysia japonica ‘Lanyin No.3’, respectively. When compared by relative dry shoot clipping weight, there were 11 and 25 accessions with more salinity tolerance than ‘manilagrass’ and Z. japonica ‘Lanyin No.3’, respectively. Z. pacifica was the most salinity tolerant species, Z. macrostachya, Z. matrella, and Z. tenuifolia had strong salinity tolerance, while Z. sinica, Z. japonica and Z. koreana were intermediate or sensitive. Clustering analysis of relative green leaf coverage and relative dry shoot clipping weight, indicated that the 103 Zoysia accessions could be divided into three groups: group Ⅰ (including Z5185 and Z093) was extremely saline tolerant; group Ⅱ had comparatively higher relative green leaf coverages and relative dry shoot clipping weights (>70%). It could be further divided into salinity tolerance and intermediate salinity tolerance; group Ⅲ had comparatively low relative green leaf coverage and relative dry shoot clipping weight, and could be divided into weak and sensitive salinity tolerance at a Euclidean distance of 3.

Effects of nitrogen strategies on carbon and nitrogen metabolism of maize in wheat/maize/soybean relay intercropping system

DENG Xiao-yan, WANG Xiao-chun, YANG Wen-yu, ZHANG Qun

2012, 21(4):  52-61. 

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Effects of nitrogen application strategies which contained five different nitrogen application rates: 0, 90, 180, 270 and 360 kg N/ha and three different assigning proportions (basic N∶jointing N∶huge bellbottom N): 5∶0∶5, 3∶2∶5 and 5∶2∶3 on carbon and nitrogen metabolism of maize in wheat/maize/soybean relay intercropping system were studied by two factors randomized trials using Chuandan 418 material through two years’ field experiment. Wheat/maize/soybean relay intercropping system which was a new planting pattern could increase grain yields greatly because of soybean nitrogen fixation, inter-specific nitrogen competition and facilitation and nitrogen transfer. The results showed that, the accumulation of total sugar and nitrogen of leaves and stem/sheath and also the activity of nitrate reductase, glutamine synthetase and sucrose phosphate synthase of ear leaves which were the key enzymes to the carbon and nitrogen metabolism increased with the increasing of nitrogen fertilizer application when the amount of nitrogen fertilizer was under 270 kg N/ha, however, the results were opposite while the nitrogen levels were beyond 270 kg N/ha. For two years, the amount of nitrogen fertilizer which was 270 kg N/ha had the optimal performance, and then came 180 kg N/ha, the results of nitrogen treatment which were 180 and 270 kg N/ha were significant or quite significant to the compared group. The average decreasing rate of C/N in leaves were 26%, 25%, 21%, 23%, respectively, but in stem/sheath, it remained a relatively low level when the amount of nitrogen fertilizer was 270 kg N/ha, leaves whose nitrogen fertilizer was 270 kg N/ha still had an efficient synthetic ability in milking stage, and also remained a relatively low level of C/N in stem/sheath. Different assigning proportions had different effects on carbon and nitrogen metabolism, that was, 3∶2∶5>5∶0∶5>5∶2∶3, it was obvious that the postponing of nitrogen application could improve the matter production, and also increase the activity of nitrate reductase, glutamine synthetase and sucrose phosphate synthase of ear leaves, it was significant compared to antedisplacement of nitrogen application. As a result, nitrogen strategies in combination with wheat/maize/soybean relay intercropping system can obviously improve the carbon and nitrogen metabolism of maize, and then, realize the sustainable crop production. In combination with matter production and the performances of the key enzymes, the best nitrogen application strategy was 270 kg N/ha and 3∶2∶5.

Effects of salt stress on seed germination and seedlings growth of salt-tolerant line and salt-sensitive line of maize

PENG Yun-ling, LI Wei-li,WANG Kun-ze, WANG Han-ning

2012, 21(4):  62-71. 

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Salt stress affects plant growth and development and reduces productivity of crop. Maize (Zea mays) is moderate sensitive to salt. Screening and studying maize germplasm resistant to salt have certain directive function on improving salt-tolerant germplasm resources and breeding salt-tolerant variety, and have certain theoretical meaning of genetic mechanism of salt tolerance in maize. The study will focus on the comprehensive comparison of salt-tolerant properties change of salt-tolerant lines 8723, 81162 and salt-sensitive line P138 at germination and seedling stages under salt stress, in order to probe into salt-tolerant mechanism in maize, to provide the materials for breeding resistant-salt variety and discovering genes related to salt tolerance and to lay the foundation for salt-tolerant genetic mechanism in maize.Seed germination and seedling growth of salt-tolerant lines 8723, 81162 and salt-sensitive line P138 of maize under different concentrations of NaCl stress were determined in this experiment. The experimental results indicated that, with the increase of salt concentration, there were higher germination rate, germination potential, germination index, activity index, plumule length, and lower salt injury index, of salt-tolerant line with a small change at seed germination stage, compared with salt-sensitive line. A study of salt-tolerant lines and salt-sensitive line under different concentrations of NaCl stress in seedling stage showed that the height of seedlings, root length, fresh weight of the three inbred lines all decreased with increasing concentrations of NaCl. The decrease rate of these indices for the salt-tolerant lines was all less than those for the salt-sensitive inbred line. The results of physiological changes under different concentrations of salt stress indicated that there were higher relative water content and lower relative conductivity of organization of external seepage of salt-tolerant lines with a small change, compared with salt-sensitive line. To analyze all experimental results, salt-tolerant line 8723 had stronger tolerant than 81162.

Effect of water stress on the growth of kinggrass

WEN Cui-ping, LI Wei, QI Zhi-ping, TANG Shu-mei

2012, 21(4):  72-78. 

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A pot culture experiment was used to study growth and mechanisms of physiological response of kinggrass (Pennisetum purpureum×P. glaucum) in different soil moisture conditions to provide a reference for rational water use in kinggrass production. With a reduction of soil moisture content, the fresh weight, dry weight, organization water content and relative water content gradually decreased while water sufficiency deficiency and free proline of kinggrass gradually increased. The most suitable soil moisture content for kinggrass was 65%-75% of field capacity, and kinggrass could grow normally at 55%-95% of field capacity, but growth was limited at 5%-45% or during flooding.

The influence of fertilization on photosynthesis and yield of oriental lily “Sorbonne” under the alkaline soil in northwest China

ZHANG Fen-fen, SUN Juan, XIE Zhong-kui

2012, 21(4):  79-87. 

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The area with cold and cool weather in northwest China is suitable for Lily’s growth, but the alkaline soil is an important factor to reduce’s lily yield and quality. The field experiments were conducted to examine the influences of peatmoss application and different fertilizer elements (N, P, K, Ca) on yield, photosynthetic characteristic, photosynthetic pigments content, growth index and dry matter accumulation of oriental Lilies “Sorbonne”. The results showed that the ball yield, dry weight of bulb had no significant difference under the peatmoss application treatments,but the dry/fresh ratio of bulb is reduced significantly. The production performance of “Sorbonne” including photosynthetic efficiency, leaf area index and dry matter accumulation under the fertilizertreatment without N or Ca was better than that used these, and without Por K these index were generally low. It was showed that “Sorbonne” growes well in the test area (Longde, Ningxia province) which climate condition is appropriate for lily planting. The application of peatmoss has not obvious function to improved lily yield and not have effectively improved action to alkaline soil; The excessive use of N or Ca fetilizer in alkaline soil will influence the absorption of trace elements and causing lily physiological deficiency, so the lily plangting in alkaline soil should be reasonable in order to ensure the quality and yield.

Comparison of leaf quality and normal chemical components of flue-cured tobacco from different areas in Sichuan

LU Li-ming, ZHU Liang, LEI Qiang, YE Li-hua, DU Wei-min

2012, 21(4):  88-97. 

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This study was set up in different tobacco-growing areas in Sichuan province to study different ecological conditions on the leaf appearance quality, internal quality, and chemical composition. Leaf appearance quality of tobacco samples from Dechang, Yuanba and Yanbian were better than others, while tobacco samples from Dechang and Yanbian with good sensory quality. Determination of chemical composition of tobacco leaves showed that tobacco samples from all experimental sites were with higher leaf total sugar and reducing sugar content. In the total alkali content, all experimental sites with still relatively high content of upper leaves (basically more than 2.5%), while the lower and middle leaves with appropriate content. In total nitrogen and chlorine content of leaf samples, all were at the appropriate level within the scope of 1.5%-2.5% basically. Potassium content of all samples varied accordingly, with the highest of 2.46% and the lowest concentration of 1.50%. Leaf petroleum content of all samples were more than 2.0%, while organic acid content of most samples were greater than 16.0%.In the respect of sugar to alkali ratio, most samples were in suitable range of 8-12. The results of this study indicate that the most suitable regions for high quality tobacco production are Panzhihua and Liangshan area.

Establishment of a highly efficient regeneration system of switchgrass artificial spike buds

CHAI Guai-qiang, XU Kai-jie, WANG Yong-feng, SUN Feng-li, SONG Li-li, LIU Shu-dong, XI Ya-jun

2012, 21(4):  98-104. 

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With inflorescence of three genotypes of Xiji No.1, Xiji No.2, Xiji No.3 as materials, using single factor design consider factors including genotype, panicle length, phytohormone, the length of spike buds in the initial cutting period and in mass cultivating period, the carbon source, pH, spike buds cutting way and root induction medium, to optimize the regeneration system of switchgrass (Panicum virgatum) artificial spike buds. The optimal regeneration system was: genotype Xiji No.1, panicle length 1.5 cm, 3.0 mg/L 6-BA+0.1 mg/L 2,4-D as phytohormone, the length of spike buds in the initial cutting period and in mass cultivating period was 1.5 cm, maltose as carbon source, pH 5.8, vertical spike buds cutting, and 1/2 MS as root induction medium. The proliferation efficiency of switchgrass artificial spike buds might reach up to 4 167.00%.

Comparative study on leaf epidermis submicroscopic structure of Cynodon dactylon under two habitats

ZHOU Cun-yu, FEI Yong-jun, LIU Zhi-xiong, KE Lin, YANG Min

2012, 21(4):  105-115. 

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The leaf epidermis submicroscopic structures of five varieties of Cynodon dactylon and wild bermudagrass planted in rural area soil and vegetation concrete were observed under scanning electron microscope (SEM). The shape, size and density of stomata on the leaf epidermis, epidermal appendages (mastoids, bristles etc.) of C. dactylon grown under the two habitats were compared. The five varieties and wild C. dactylon used in the experiments showed morphological responses to saline stress, and mastoids on upper and low epidermis increased, compared with control. On the epidermis of some varieties, such as Sahara, Hawk, and wild type, the mastoids around stomata distributed regularly, resulting in stomatal apparatuses below the cells around them. As the stomatal resistance increased, transpiration rate might decrease, and water usage efficiency might increase. Compared with control, increased stomatal density on upper and lower epidermis occurred on Kashi, Sahara, Heaven, and Hawk. According to the stomatal characteristics of the varieties grown on vegetation concrete, high stomatal density occurred on Kashi and Sahara. In general, among the five varieties of C. dactylon and wild bermudagrass used in this study, Sahara, Hawk, and Kashi showed better adaptation to vegetation concrete.

A study on genetic diversity of Avena germplasm resources detected by ISSR

LIU Huan, MU Ping, ZHAO Gui-qin

2012, 21(4):  116-124. 

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Genetic diversity of 42 Avena sativa varieties and 6 Avena nuda varieties from China, Canada, America, Europe and other countries was studied using inter-simple sequence repeat (ISSR) molecular markers. Eight primers detected 144 polymorphic bands, and the proportion of polymorphic fragment was 86.1%. Based on Nei’s index, the average variation coefficient of A. sativa and A. nuda were 0.203 6 and 0.201 5, and of the Shannon diversity index were 0.325 9 and 0.305 8, respectively. The similarity coefficient of all cultivars was 0.583 3-0.941 7, and genetic distance was 0.060 1-0.539 0 indicating a rich genetic diversity of Avena, with A. sativa varieties having a higher genetic diversity than that of A. nuda varieties. Based on cluster and principal component analyses of the ISSR fingerprinting data, the 48 varieties could be divided into 5 groups. In most cases, accessions from the same continent were classified into the same group. The geographical distribution of genetic diversity in A. sativa and A. nuda were divided into two groups at 0.66, which was in accordance with traditional morphologic and other molecular marker classifications. The genetic relationship revealed by ISSR was consistent with that from other sources.

A study on genetic analysis of F₂ hybird progenies by molecular markers in annual ryegrass (Lolium multiflorum)

YANG Wen-xuan, MA Xiao, ZHANG Xin-quan, HUANG Lin-kai, MIAO Jia-min

2012, 21(4):  125-133. 

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Six parental cultivars of Lolium multiflorum and eighty F₂ progenies of nine cross combinations were used in this study. SRAP and SSR markers were used to analyze genetic relationship of 86 L. multiflorum accessions.15 and 16 primer pairs were selected by SRAP and SSR, respectively. 16.7 bands were amplified per primer pairs on average and percent of polymorphic bands was 68.88% in SRAP analysis. The average number of bands per primer pairs was 14.75 and percent of polymorphic bands was 58.05% by SSR markers. The conclusion of analyze by clustering tree showed that progenies from the same F₂ cross combination clustered together, except the combination Changjiang No.2×Jumbo, Changjiang No.2×Aubade;the genetic distance from F₂ progenies to male parent or female parent was so approximate. Meanwhile, the reliability of UPGMA dendrogram for L. multiflorum F₂ progenies and parental cultivars by SRAP markers was higher than SSR.

Analysis of the genetic structure of Spartina alterniflora populations in China based on cpDNA trnT-trnF sequences

WU Juan-zi, WANG Qiang, ZHONG Xiao-xian, CHEN Jian-qun

2012, 21(4):  134-140. 

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Polymorphism of the chloroplast DNA (cpDNA) trnT-trnF sequence from eight Spartina alterniflora populations, including 80 samples in China, was measured. Three haplotypes, which were distinguished by two single A insertion/deletions (Indel), were relatively lower haplotype diversity types (Hd=0.379) than the native populations, which indicated an obvious bottleneck effect. The mean values of Nei’s genetic distance and genetic differentiation index (Fst) of eight populations were 0.064 and 0.092, and Nei’s genetic distances ranged from 0.000 to 0.184. AMOVA revealed that there was 9% genetic variation in the total population. At the cpDNA level, there was a relatively lower level of genetic differentiation but S. alterniflora populations had a higher genetic differentiation within populations in China.

Cloning and analysis of the MADS-box gene WM8 of Elymus nutans

ZHANG Miao-qing, ZHANG Ji-yu, LIU Zhi-peng, WANG Yan-rong, ZHANG Lei

2012, 21(4):  141-150. 

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The full length MADS-box gene EnWM8 was isolated from Elymus nutans by homology cloning, and was submitted to GenBank (accession number JF683846). Analyses of the cDNA sequence showed that EnWM8 was 1 196 bp and encoded 275 amino acids, typical of the MIKC-type MADS-box genes with a typical MADS-box domain and K semi-conservative district. It is speculated that it has some connection with flower development, fruit ripening etc. The deduced amino acid sequence showed that there were 95.62%, 96.72%, 96.28% similarities between the gene and Triticum aestivum genes WM8, AGL29, and fruitful-like. The phylogenetic tree deduced by DNAMAN software indicated that EnWM8 had a close evolutionary relationship with the TaWM8 of T. aestivum, and was distantly related to the AtWM8 and AtAGL29 of Arabidopsis. The WM8 protein of E. nutans is a hydrophilic and basic protein with a molecular weight of 13 726.7 Da: the theoretical isoelectric point is 9.14. It has no membrane structure and is mainly located in the nucleus. There are many α-helix, random coil and extended strand structures. These results are a basis for further research on flower development, seed maturation and other mechanisms of E. nutans at the molecular level.

Isolation and characterization of Nitraria sibirica actin gene

WANG Li, LI Fei-feng, ZHANG Wen-bo, CHEN Gui-lin, LIN Xiao-fei

2012, 21(4):  151-158. 

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Nitraria sibirica actin gene (NsAct) was cloned using degenerated-PCR and RACE technique, and gene structure and expression pattern were analyzed. Full-length sequence of the NsAct cDNA contains 1 831 bp, which has a 1 134 bp open reading frame (ORF) encoding 377 amino acids. Genomic DNA of the NsAct contains 2 913 bp, including 5 extrons and 4 introns. The NsAct amino acid sequence shows a high homology to that of the other plants, and phylogenetic tree generated from the nucleotide sequences of plant actins revealed that the NsAct shows close genetic relation with Mangifera indica (sapindales). The NsAct equally expressed in root, stem, and leaf, and no obvious change in expression level was observed under stress conditions of drought, salt, cold, and exogenous abscisic acid (ABA).

Cloning and subcellular localization of a WRKY transcription factor gene of Medicago sativa

CHEN Ting-ting, YANG Qing-chuan, DING Wang, KANG Jun-mei, ZHANG Tie-jun, ZHANG Xin-quan

2012, 21(4):  159-167. 

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The WRKY transcription factors play important roles in plant growth and development. A cDNA sequence of Medicago sativa WRKY transcription factor gene was isolated by electronic cloning and RT-PCR (reverse transcription polymerase chain reaction), and was named MsWRKY56. The cDNA sequence was 1 267 bp and contained a maximum open reading frame of 951 bp coding for 317 amino acids. Subcellular localization analysis of a construct with the transient expression vector of the MsWRKY56 gene showed that the MsWRKY56 protein was localized in the nucleus and was thus consistent with the general character of subcellular localization of transcription factors. This research forms a basis to further study the structure and function of the gene encoded protein.

A study on Agrobacterium tumefaciens-mediated transformation of Medicago sativa with the AtCBF1 gene

XU Chun-bo, WANG Yong, ZHAO Hai-xia, MI Fu-gui

2012, 21(4):  168-174. 

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The cold resistance effect of the cold-induced transcription activator CBF1 (C-repeat-binding-factor) gene on Medicago sativa was studied by amplifying an AtCBF1 gene and cloning it by polymerase chain reaction (PCR) from the genomic DNA of Arabidopsis thaliana. The length of the DNA cloned fragment was 642 bp. Compared with the CBF1 sequence in GenBank, the sequence homology rate was 99.84%. On the basis of the CBF1 gene, the plant expression vector pBI121-CBF1 was constructed with the AtCBF1 gene and M. sativa was transformed using Agrobacterium tumefaciens. The transformed plants were selected with kanamycin. An electrophoretic band of 650 bp was obtained by PCR and RT-PCR (reverse transcription polymerase chain reaction). The AtCBF1 gene was expressed in M. sativa. This research provides a good basis for breeding new M. sativa varieties with cold resistance.

Construction of integration QTL map and identification of candidate genes for stay-green in maize

FANG Yong-feng, LI Yong-sheng, BAI Jiang-ping, MU Ping, MENG Ya-xiong, ZHANG Jin-lin, WANG Han-ning, SHANG Xun-wu

2012, 21(4):  175-185. 

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Leaf senescence is a character of plant development. Delayed leaf senescence or stay green character has received considerable attention because of its negative impact on photosynthesis and its role in nutrient redistribution within the plant. In the past few decades, a wealth of QTLs (quantitative trait locus) mapping data for stay green and its related traits in maize has been produced using molecular marker approaches. In order to unlock the full potential of the information contained in these independent experiments, 173 stay-green and related QTLs in maize were collected from maize genomic database (maize GDB), and were compiled to construct the integration QTL map for stay-green in maize (Zea mays). The high-scale genetic linkage map of maize IBM2 2008 Neighbors was used as reference and the map were constructed with BioMercator 2.1 software based on the method of meta analysis. Five consensus QTL for maize stay green were identified on maize chromosomes 1, 4, 5 and 9, respectively. After project the consensus QTL region on maize physical map of B73 RefGen_v2, a total of 1 445 candidate genes in the consensus QTL region were discovered and downloaded from Plant GDB(http://www.plantgdb.org/).Meanwhile, according to the results of gene ontology analysis, most candidate genes might take part in the cell development, catalytic process, enzymatic activity and other biological progresses. The sequences of eight stay-green candidate genes were identified by comparatively analyzing the sequences of stay-green gene sequence from other crops. Using a syntonic conservation approach, which is used to comparatively analyze the rice genetic map and maize physical map, one rice gene (sgr) that is coding for the senescence-inducible chloroplast stay-green protein was projected onto the physical map of maize B73RefGen_v2. Therefore, the results suggested that this approach provided an useful tool for identifying QTL conferring stay-green and other candidate genes in maize.

Effect of adding coenzyme and lactic acid bacteria on fermentation quality of mixed silages of tall fescue (Festuca arundinacea) and common vetch (Vicia sativa) in tibet

WANG Qi, YU Cheng-qun, LI Zhi-hua, ZHAO Qing-jie, Masataka Shimojo, SHAO Tao

2012, 21(4):  186-191. 

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The aim of this study is to evaluate the effects of adding coenzyme, LAB and their combinations on the fermentation qualities and residual water soluble carbohydrates of mixed silages of common vetch and tall fescue during ensiling. The treatments were as follows: control (C),coenzyme (E), LAB, coenzyme+LAB(E+LAB), these silos were opened on 7, 24 and 60 days after ensiling and the fermentation quality was analyzed. Compared to the control silage, adding of E and LAB were efficient in improving the fermentation quality of mixed silages, and the combination addition further increased the LA content and decreased the pH value. The E combination treatments including the E alone showed higher acetic acid and total volatile fatty acids contents as compared with the control and LAB treated silages, the propionic and butyric acid were hardly found in all silages during ensiling. The combination treated silages showed highest water soluble carbohydrate content and lowest ammonia nitrogen/total nitrogen through the whole ensiling. These indicated that the E and LAB were of synergistic effects on the fermentation quality. From the above results it was suggested that the combination addition of coenzyme and LAB is better for improving the fermentation quality of mixed silages of common vetch and tall fescue in this experiment.

Effects of adding lactic acid bacteria and pineapple peel on Stylosanthes silage quality

SHEN Cheng-li, CHEN Ming-xia, LI Guo-dong, ZHANG Jian-guo

2012, 21(4):  192-197. 

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Stylosanthes is a legume forage which has high protein content and good nutritional quality in tropical and subtropical areas. To promote the utilization of Stylosanthes, the effects of adding lactic acid bacteria and pineapple peel on the silage fermentation quality and aerobic stability were studied after 60 days storage. The experimental treatments were CK (no additive), LQ (commercial inoculant), LF (Lactobacillus fermentum), LP (L. plantarum), LS (L. rhamnosus), B (20% pineapple peel), BLQ (B+LQ), BLF (B+LF), BLP (B+LP), and BLS (B+LS). Stylosanthes silage had few water soluble carbohydrates and lactic acid bacteria, together with poor quality and a high pH (>5.0) when there were no additives. All the additives significantly reduced pH, increased lactic acid contents (P＜0.05), and considerably improved the silage fermentation quality compared with the control. The contents of butyric acid and NH₃-N in the silage with addition of pineapple peel only were significantly higher than those with only lactic acid bacteria added (P＜0.05). The pH was not significantly different from LQ, LF, and LS (P＞0.05). There were no significant differences between the four lactic acid bacterial treatments in any of the indices (P＞0.05) except that LP had a higher acetic acid content and lower butyric acid content than the others. Combining pineapple peel and any lactic acid bacteria improved the silage fermentation quality of Stylosanthes, especially for BLP, which had a lower pH, lower acetic acid and NH₃-N contents, higher lactic acid bacteria content and, higher ratio of lactic acid to acetic acid. All the silages including the control had good aerobic stability.

A study on ovicidal activities of extracts from 35 species of plants (including Coronilla varia) against Mythimna separata

LIU Min-yan, HU Guan-fang, YU Hai-tao, NIU Shu-jun, LI Yu-qi

2012, 21(4):  198-205. 

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The ovicidal activities of extracts from 35 species of plants (including Coronilla varia) against Mythimna separata were measured by immersion methods. The acetone extract from Levisticum officinale seeds, chloroform extract from Cnidium monnieri seeds, methanol, petroleum ether and ethyl acetate extracts from Ricinus communis seeds, methanol, ethanol, acetone and ethyl acetate extracts from C. varia roots all had strong ovicidal activities against M. separata. Corrected non-hatching ratios of eggs were 100% after 5 days treatment. Extracts of 75% methanol, and petroleum ether from L. officinale roots and of methanol and petroleum ether extracts from L. officinale seeds had strong ovicidal activities with corrected non-hatching ratios of eggs of 39.65%, 35.31%, 55.99%, 34.51% respectively. Petroleum ether extracts from C. varia roots, Datura stramonium seeds and Abutilon theophrasti seeds had some ovicidal activities - corrected non-hatching ratios of eggs were 11.45%, 11.79% and 10.60% respectively. Other extracts had no ovicidal activity. Four species of plants (C. varia,　L. officinale, C. monnieri and R. communis) with effective ovicidal activities are worth further research and development.

Optimization of the extracting process for alkaloids from Dicranostigma leptopodum by response surface analysis and study on its antibacterial activity in vitro

ZHAO Qiang, YU Si-jiu, WANG Ting-pu, YUAN Yi-jun

2012, 21(4):  206-214. 

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In this paper, the Dicranostigma leptopodum was researched, on the basis of single factor level determination, the optimal extraction conditions were obtained by using the response surface analysis, and the concentrated liquid of extract response surface analysis was measured by antibacterial activity, moreover, the transmission electron microscopy images of Escherichia coli of treated with concentrated liquid of extract from D. leptopodum was discussed. The experiment results demonstrated that the optimum conditions were liquid to solid ratio was 15 mL/g, time of ultrasound was 35 min, refluxing time was 2.5 h, alcohol was 65%, and the content of alkaloid from D. leptopodum was 9.33% in the optimum extraction process condition; the optimal extraction conditions were obtained by using the response surface analysis of E.coli, Candida albicans and Pseudomonas aeruginosa of minimal inhibitory concentration and minimal bactericidal concentration were 0.20, 0.15, 0.35 mg/mL and 0.15, 0.10, 0.30 mg/mL. They were observed under transmission electron microscopy to everest to E. coli antibacterial activity effect significantly remarkable. The results also showed that the response surface analysis to D. leptopodum spend alkaloid extraction process optimization are reasonable.

A study on resource investigation, application and protection of wild herbaceous plants of the Yuntai Mountain in Lianyungang

ZHANG Jia-ping, DING Yan-fen

2012, 21(4):  215-223. 

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As an important germplasm resource pool in the north of Jiangsu Province, the Yuntai Mountain in Lianyungang abounds in resources of wild herbaceous plants, most of which have high ornamental and economic values although there is no protection and utilization of them. Through route investigations and quadrat surveys and based on literature reviews, the basic types of herbosa and herbaceous plant flora of the Yuntai Mountain were studied. The ornamental characteristics of 106 selected species of wild herbaceous plants with high ornamental value and special ecological significance are discussed. The best way to use these 106 species were analyzed, mainly focusing on the prospect of landscape application and referring to ecological significance of virescence, restorations of saline and alkaline lands, as well as to the economic uses as medicinal and food plants. Finally, three types of key herbaceous plants were selected for their significance as species for diversity conservation. Some protective measures are also discussed, mainly in combination with utilization for landscape building. This study provides references for resource investigation, application and protection of native wild herbaceous plants in the north of Jiangsu and Anhui Province with similar climatic types.

Study the change of NDVI and climate factors and carrying capacity and their correlation in Maqu County, Gansu

HUA Li-min

2012, 21(4):  224-235. 

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The paper reports on a study conducted in Maqu County located in eastern Tibet Plateau from 1982 to 2005. It was focused on the change of NDVI, climate factors and carrying capacity and their correlation, as well as the time lag effect between NDVI and temperature and precipitation. The correlation coefficients between NDVI and temperature and precipitation over the same period and the effect of including data from a prior period were analyzed under 16 combinations of temperature or precipitation (4 time durations by 4 time lags). The annucal changes of NDVI in spring and summer were significantly increased and their increasing range were 0.019/10 a and 0.022/10 a respectively. The annual change of seasonal and annual temperature as well as annual accumulated temperature above 0℃ were significantly increased over the study period and their increasing range were 0.5-0.7℃,0.6℃ and 121.5℃ respectively. The changes of seasonal and annual precipitation were not significantly different. The change of temperature in summer was steady but in spring and autumn it was variable. So too was the change of precipitation in four seasons. The correlation of monthly NDVI all the year round and the NDVI in spring and autumn in response to temperature at same period were significant positive or negative, and the value of correlation coefficient were 0.84, 0.77, -0.52 and 0.80 respectively. The correlation of average monthly NDVI every year in response to annual accumulated temperature above 0℃ and carrying capacity were significant positive, and the value of correlation coefficient were 0.66 and 0.45 respectively. The correlation of NDVI in response to precipitation in the current month and accumulated precipitation in two months prior (time durations: three months) were highly significant, the temperature in the current month and one month prior (time durations: two months) was also highly significant. By taking lag times into account we found significantly high correlations with the NDVI increase during the growing seasons. The increase of temperature in early growth stage (April) promoted vegetation growth. Generally precipitation later in the year had negative effects especially rains late in the growth stage of forage plants (August to September) as did high temperature at this time.

Study on the multiple-factors associative effects of forage

GAO Jing, JIA Yu-shan, WANG Xiao-guang, LIU Ting-yu, FU Jun-ping, DING Xia

2012, 21(4):  236-243. 

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This thesis is basis on the theory of multiple-factors associative effects index (MFAEI), and adopts in vitro method to determine the pH, gas production (GP), in vitro digestibility organic matter (IVDOM), microbial protein (MCP), and volatile fatty acid (VFA). To select the priority of forage formula, the alfalfa, tomato pomace, corn stalks and wheat straw are employed. According to results, the priority of forage formula are as follow: Alfalfa/tomato pomace/corn stalks=30/10/60, the values of multiple-factors associative effects is 0.80; Alfalfa/corn stalks=50/50, the values of multiple-factors associative effect is 0.85; Alfalfa/tomato pomace/wheat straw=30/20/50, the values of multiple-factors associative effect is 0.82; Alfalfa/wheat straw=60/40, the values of multiple-factors associative effect is 0.78. These forage formulas could express the maximum of positive combined effect between forage, control and eliminate the negative combined effect to perform the maximum productivity of herbivorous livestock and reduce the feeding cost.

Effects of metallothionein on expression of lymphocyte apoptosis genes and the HSP70 gene of dairy cattle under heat stress

LUO Jia-jie, WU Zong-ming, ZHANG Bin, LI Li-li, WU Li-zhuan, CHEN Yu-guang, XIAO Ding-fu, BI Xiao-yan

2012, 21(4):  244-251. 

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Effects of exogenous metallothionein on expression of lymphocyte apoptosis genes and the HSP70 gene of dairy cattle under heat stress were studied with 25 lactating Chinese Holstein cows. They were randomly divided into five groups (A, B, C, D and E, five per group), and supplemented with 0, 16.0, 24.0, 32.0 and 40.0 mg Zn-MT, respectively, by intravenous injection. Blood samples were collected at 1st, 7th and 14th day, and the levels of HSP70, Bcl-2, Bax and p53 gene expressions in lymphocytes were measured. The milk yield of the cows in group B was more than those in groups A, C, D and E by 20.94% (P＜0.05), 15.83% (P＞0.05), 10.94% (P＞0.05) and 8.85% (P＞0.05), respectively. The level of HSP70 gene expression in group D was more (P＜0.05) than that in group A, but there were no significant differences (P＞0.05) between groups A and B, C, and E. The levels of Bcl-2 gene expression of groups B, C, D, and E were more than that of the control group (A), and there was a significant difference (P＜0.05) between groups A and C. The levels of Bax gene expression in groups B and D were lower than that in group A by 22.00% (P＞0.05) and 13.00% (P＞0.05), while the levels of p53 gene expression in groups C and E were lower than that in group A by 22.00% (P＞0.05) and 34.00% (P＞0.05), respectively. Exogenous Zn-MT can improve milk producing ability and regulate the levels of HSP70, Bcl-2, Bax and p53 gene expressions in dairy cattle in a dose-dependent manner.

Effects of different nutrition levels in total mixed rations on production performance, apparent digestibility, and slaughter performance in yard feeding lambs

MA You-ji, WANG Bao-yi, LI Fa-di, ZHAO You-zhang, HU Xiang

2012, 21(4):  252-258. 

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The effects of three nutrition levels (A₁, 0.7×NRC, A₂, 0.8×NRC, A₃, 0.9×NRC) in total mixed rations on production performance, apparent digestibility and slaughter performance was evaluated. Forty-eight lambs [SA Mutton Merino(♂)×Gansu alpine fine wool sheep (♀)] were randomly divided into three groups for a two months feeding trial. The average daily weight gains of the A₂ and A₃ groups were significantly (P<0.01) higher than that of the A₁ group. There was no significant difference between A₂ and A₃. The average daily gain of ram lambs was significantly (P<0.01) higher than that of ewe lambs. Different nutrition levels had significant effects on apparent digestibility of Ca, total phosphorus (TP), neutral detergent fibre (NDF) and acid detergent fiber (ADF) (P<0.01). Sex factors had significant effects on apparent digestibility of Ca and TP (P<0.01). There were no difference in slaughter indexes (P>0.05) but the slaughter rate, cooking rate and loin eye area of hybrid lambs were significantly higher than those of Gansu alpine fine wool sheep. In summary, the 0.8×NRC nutritional level was better for fattening hybridized lambs of crossed SA Mutton Merinos, and ram lambs grew better than ewe lambs at the same nutritional levels.

Effects of SARA induced by high level concentrate on cortisol concentrations in serum and rumen fluids of the goats during lactation

JIA Yuan-yuan, WANG Shao-qing, CHANG Guang-jun, ZHANG Yuan-shu, ZHUANG Su, NI Ying-dong, SHEN Xiang-zhen, CHEN Jie, ZHAO Ru-qian

2012, 21(4):  259-266. 

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Seven goats fitted with permanent rumen cannulas in mid-lactation were used in a 2×2 latin square experiment design with different concentrate to roughage ratio of 6∶4 and 4∶6 respectively. Set up the subacute ruminal acidosis (SARA) model by the diet with concentrate to roughage ratio of 6∶4 to study the variations of cortisol concentration in the blood and rumen fluid and glucocorticoid receptor mRNA of goat in mid-lactation. SARA was induced successfully by feeding the SARA group with the diet with concentrate to roughage ration of 6∶4. pH of the rumen fluid of SARA group was below 5.8 after feeding, lasting for about 6 hours while pH of the rumen fluid of control group (concentrate to roughage ratio of 4∶6) was above 6.0. pH and lactic acid of the rumen fluid, LPS and cortisol of rumen fluid and blood were affected by dietary modulation (P<0.05). Comparing with that in the control group, the concentration of lactic acid in rumen fluid of SARA group was significantly high (P<0.01) before feeding and then decreased in four hours after feeding and increased during 6-10 h after feeding, significantly higher (P<0.01). Concentration of LPS in rumen fluid was no significance between the two groups at the same time points (P>0.05), but concentration of LPS in blood of SARA group was significancantly higher than control in 0 and 6 h after feeding (P<0.05); the concentration of cortisol in blood and rumen fluid of SARA group was higher than that in the control group (P=0.05) before feeding, but there was no significance between the two groups after 6 hours after feeding (P>0.05); concentration of cortisol in rumen fluid was significantly higher than control in 2,4 and 6 h after feeding, but no significance between the two goups after 10 hours after feeding (P>0.05). Results of Real-time PCR showed that GR mRNA downgraded significantly (P<0.05). Our results indicates that SARA goats were in stress situation with a significantly higher glucocorticoid concentrations in serum and rumen fluids, accompanied with down-regulation of GR mRNA expression in liver which will change the status of metabolism and nutrition redistribution in liver.

A study on water resource carrying capacity in the Shule river basin based on ecological footprints

ZHANG Jun, ZHANG Ren-zhi, ZHOU Dong-mei

2012, 21(4):  267-274. 

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Water resource carrying capacity and ecology deficit in the Shule river basin were studied using ecological footprints. The capacity gradually increased from 1 696.35 ha to 1 925.26 ha, the total ecological footprint from 19 714.23 ha to 32 236.35 ha, and ecological deficit from 18 017.88 ha to 30 311.08 ha from 2003 to 2007. The water resource ecological carrying capacity is presently overloaded in the Shule river basin. Because of increasing population growth and farmland expansion, there are more pressures on the regional water resources. In the future, measures such as taking an appropriate immigration policy, increasing public awareness of water conservation education, adjusting the industrial structure, and controlling the planting area should be carried out.

A comprehensive evaluation of turfgrass quality based on a BP and RBF neural network model

XIAO Bo, SONG Gui-long, HAN Lie-bao, BAO Yong-xia, LI Fei-fei, CHEN Ai-xia

2012, 21(4):  275-281. 

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Based on the recent turfgrass quality evaluation system, eleven indexes (density, texture, color, uniformity, green period, disease resistance, coverage, traffic tolerance, seedling establishment, turf strength and biomass) were used to select 20 Poa pratensis cultivars in 2010. The values of eleven indexes from 15 of the P. pratensis cultivars were selected as input data for the system using the principles of neural networks and the Matlab neural network toolbox. The output was expert graded data. Performance optimization was carried out by running the neural networks with different parameters and then models of the BP and RBF neural networks for evaluation of turfgrass quality were established. Methods of establishing neural network models and steps for Matlab are listed. Quality of the other 5 P. pratensis cultivars was evaluated using the trained neural network model. The predicted errors of the RBF neural network were less than 2% and the predicted errors of the BP neural network were more than 5% when they were applied as a comprehensive evaluation of turfgrass quality. Therefore the RBF neural network with smaller error odds was able to provide a more accurate evaluation of turfgrass quality than the BP neural network and it can be used to evaluate turfgrass quality. Compared with traditional methods, such as the weighting method, analytic hierarchy process, and fuzzy synthesis, the RBF neural networks accuracy reduces the influences of subjective factors and simplifies the calculating procedures. It provides a new idea for comprehensive evaluation of turfgrass quality.

A study on early warning of grassland fire disaster risk in Hulunbeier

CUI Liang, ZHANG Ji-quan, BAO Yu-long, TONG Zhi-jun, LIU Xing-peng

2012, 21(4):  282-292. 

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Grassland fire disaster is one of a sudden, destructive, and hard to disposal grassland disasters, it caused a great threat to the pastoral people’s lives and property in Hulunbeier grassland fire statistics on statements and related meteorological data from 1994 to 2005 and theories of risk of natural disasters, and of regional disaster system, an astoral. In this research, early warning of grassland fire disaster risk was modeled through the study of six livestock counties of Hulunbeier grassland, based on data of disaster early warning. Logistic regression model was used in the identification of the key factors influence the early warning of grassland fire disaster risk; in the calculation the weight of individual indicators, analytic hierarchy through scoring by experts was used; grid GIS technology combined with regression analysis was used in the spatial distribution of indicators of the constituency which will make space rating scale more accurate; warning source of endogenous and exogenous sources of warning signs of Hulunbeier grassland fires was analysis through weighted comprehensive analysis; with the optimal partitioning of the fire cases from 1994 to 2004, early warning threshold was identified and was divided into the blue, yellow, orange and red alert. Grassland fire risk warning has been calculated on Hulunbeier, take all the fires on Hulunbeier grassland in 2005 for instance. It shows a good agreement between high risk fire areas of early warning and fire point, which, in terms, tested the accuracy of the model in a certain degree.

A snow cover mapping algorithm based on MODIS data in Qinghai Province

WANG Xue-lu, WANG Wei, FENG Qi-sheng, LV Zhi-bang, LIANG Tian-gang

2012, 21(4):  293-299. 

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Using the MODIS (moderate resolution imaging spectroradiometer) surface reflectance product of MOD09GA, the daily composite product of MOD10A1, and snow depth data observed in climate stations, the snow classification accuracy under different NDSI (normalized difference snow index) thresholds were studied. The snow classification accuracy of these snow cover maps were evaluated to find a credible NDSI threshold in Qinghai Province. 1) With a clear sky, the snow classification accuracy of MOD10A1 was 86.01% when snow depth was more than 3 cm. 2) In the study areas, the credible NDSI threshold value was 0.37. When snow depth was more than 3 cm, a snow classification accuracy of user-defined images under clear skies was 90.37%, with an overall accuracy of 99.51%, commission error of 0.22%, and omission error of 9.63%. 3) Compared with the MOD10A1 product, the user-defined snow cover images had higher overall accuracy and snow classification accuracy for different snow depths. Thus, the new NDSI threshold was more suitable for this study area in snow cover mapping.

Research progress on application of recycled water for irrigating green plants

JIA Zhe-feng, ZHOU Hai-feng, CHANG Zhi-hui

2012, 21(4):  300-306. 

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Recycled water has been widely used for irrigating green plants. The latest research work on the influence of recycled water on green plants is summarized and showed that recycled water can promote green plant growth, change physiological characteristics, optimize quality, increase mineral elements absorption and enhance the comprehensive advantages of resistance. However, because of different plant species composition and quality of recycled water, it may cause certain negative impacts, such as microelement changes, and heavy metal and sodium ion accumulation. This article briefly discusses the feasibility and possible problems associated with use of recycled water for green plants, and indicates important research directions for the future.

Seasonal dynamics of root-shoot ratio and the effect of factors in grazed and ungrazed grasslands of the Loess Plateau

LI Xu-dong, ZHANG Chun-ping, FU Hua

2012, 21(4):  307-312. 

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The allocation between above-ground and under-ground biomass is influenced by many factors such as plant species, plant age and climate conditions. It can influence carbon input from plant to soil and the carbon cycle in terrestrial ecosystems. Because it is difficult to measure the root biomass precisely, there are still some uncertainties in the root-shoot ratio (R/S), which is considered an important parameter in carbon cycle models of terrestrial ecosystems. The seasonal dynamics of R/S were investigated in grazed and ungrazed grasslands of the Loess Plateau in 2007, 2008, and 2009, and the relationships between R/S, precipitation, and air temperature were analyzed to provide useful information for prediction of under-ground biomass and carbon cycle models in terrestrial ecosystems. The seasonal dynamics of R/S in both grasslands showed an anti-parabolic pattern, with the minimum values occurring in September. The mean R/S values in the three years in the grazed grassland (3.13, 3.36 and 3.77 respectively) were significantly higher than those in the un-grazed grassland (2.55, 2.56 and 3.13 respectively) (P<0.05); At a seasonal scale, there were significant negative correlations between R/S with precipitation and mean temperature in the last two months (P<0.05). Multiple regression equations were built to better predict R/S.

Allometry analysis of reproductive ramets of Phragmites australis populations from different habitats in the Songnen Plain of China

LIU Xiu-xiang, YANG Yun-fei

2012, 21(4):  313-318. 

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Phragmites australis is a common species in the Songnen Plain of China. Two research habitats were chosen in this arid area. One was a single dominant species community in which, there was some seasonal stagnant water, the other was a Leymus chinensis + P. australis community, growing in alkaline soil with little or no stagnant water. Large random samples taken at the end of the milk stages were quantitatively analyzed for characteristics of reproductive ramets of P. australis from these two different arid habitats. There were significant differences in ramet height, module biomass, total ramet biomass, ratio of reproductive growth and allocation of module biomass in the two habitats, but not flower length or flower biomass. In the both habitats, the variation coefficient of flower biomass was the largest in absolute quantitative characters (57.73%) in the P. australis community and in the mixed community (49.87%) while the variation coefficient of reproductive allocation was the largest in terms of relative quantitative characters (36.17% and 39.44% respectively). There was a positive correlation between flower length and ramet height, but negative correlation between ratio of reproductive growth and rarmet height. Module biomass allocation, reproductive allocation and productive allocation, productive allocation and stem biomass allocation all showed significant allometry, which could be described by a power function (Y=βX^α) regardless of habitat. P. australis populations had the best ability to regulate reproductive allocation in different habitats, reflecting the strategies of the plants growth and reproduction.

A study on organic carbon and nutrient releasing characteristics of different Astragalus sinicus manure use levels in a single cropping region of subtropical China

WANG Fei, LIN Cheng, LI Qing-hua, HE Chun-mei, LIN Xin-jian, LI Yu

2012, 21(4):  319-324. 

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Organic carbon and nutrient release characteristics of different Astragalus sinicus manure use levels applied at the bloom stage in a single cropping region of subtropical China were studied using manured soil in net bags with a field moisture capacity of 70% and at ambient temperature. The speed of decomposition reached a peak within 20 days, but was low after the 60th day. On the 90th day, accumulated decomposition rates of dry material represented low (equated to 15 000 kg/ha) to high (equated to 45 000 kg/ha) manure use levels were 78.7%, 76.0% and 71.2%, respectively. Release of C, N, P, and K could be calculated with the following power function formulas: Y=13.4246X^0.4391 (P<0.01), Y=14.0314X^0.4208 (P<0.01), Y=3.5458X^0.7037 (P<0.01), Y=15.7784X^0.4213 (P<0.01). Accumulated release rates of carbon and nutrient were: K>C>N>P in the first 20 days as well as during all decomposition periods. Moreover, accumulated release rates of carbon and nutrient both steadily decreased with an increase of A. sinicus manure levels.

A study on fermentation quality of mixed silages of hulless barley straw and perennial ryegrass in Tibet

YUAN Xian-jun, YU Cheng-qun, LI Zhi-hua, Masataka Shimojo, SHAO Tao

2012, 21(4):  325-330. 

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The fermentation quality of mixed silages of hulless barley (Hordeum vulgare) straw and perennial ryegrass (Lolium perenne) was studied using the following treatments: control (100% hulless barley straw), L (80% hulless barley straw+20% perennial ryegrass), M (60% hulless barley straw+40% perennial ryegrass) and H (40% hulless barley straw+60% perennial ryegrass). The laboratory silos were opened on 7, 14 and 30 days after ensiling in triplicate and the fermentation quality was measured. The mixed silages significantly (P<0.05) increased lactic acid and water soluble carbohydrate contents, while significantly (P<0.05) reducing pH value and dry matter content. Acetic acid content was significantly (P<0.05) increased with an increase of perennial ryegrass in mixed silages. The ammonia/total nitrogen of mixed silages was lower (P>0.05) than that of the control. There was little butyric or propionic acids in all silages. Based on these results, mixed silage of 40% perennial ryegrass was best for improving the fermentation quality of hulless barley straw.