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草业学报 ›› 2024, Vol. 33 ›› Issue (9): 1-14.DOI: 10.11686/cyxb2023380

• 研究论文 •    

宁夏荒漠草原典型灌丛根际土壤酶活性及微生物代谢多样性

姚佳妮(), 刘爽, 张钧杰, 胡明珠, 代金霞()   

  1. 宁夏大学生命科学学院,宁夏 银川 750021
  • 收稿日期:2023-10-11 修回日期:2023-12-11 出版日期:2024-09-20 发布日期:2024-06-20
  • 通讯作者: 代金霞
  • 作者简介:E-mail: daijx05@163.com
    姚佳妮(1999-),女,宁夏银川人,在读硕士。E-mail: yaojiani1007@163.com
  • 基金资助:
    国家自然科学基金项目(32160023);宁夏自然科学基金项目(2023AAC03062)

Enzyme activity and microbial metabolic diversity in typical shrub rhizosphere soil in Ningxia desert steppe

Jia-ni YAO(), Shuang LIU, Jun-jie ZHANG, Ming-zhu HU, Jin-xia DAI()   

  1. College of Life Sciences,Ningxia University,Yinchuan 750021,China
  • Received:2023-10-11 Revised:2023-12-11 Online:2024-09-20 Published:2024-06-20
  • Contact: Jin-xia DAI

摘要:

开展荒漠灌丛根际土壤酶活性和微生物代谢多样性研究,对于荒漠土壤的生态修复具有重要意义。运用可见分光光度法和Biolog微平板法,对宁夏白芨滩荒漠草原内柠条、沙冬青、毛刺和猫头刺4种典型的豆科灌丛不同发育期根际土壤酶活性及微生物代谢功能多样性进行了研究。结果表明:不同灌丛各发育期根际土壤的酶活性存在显著差异。从灌丛种类来看,沙冬青根际土壤脲酶活性均显著高于其他3种灌丛,毛刺根际土壤碱性磷酸酶活性均显著低于其他灌丛。从发育期来看,营养期沙冬青根际土壤脲酶和碱性磷酸酶活性显著高于其他时期,柠条根际土壤脲酶和蔗糖酶活性显著低于其他时期;盛花期柠条根际土壤脲酶和碱性磷酸酶活性、沙冬青根际土壤蔗糖酶活性、猫头刺根际土壤脲酶和脱氢酶活性显著高于其他时期;果实期沙冬青根际土壤脲酶和碱性磷酸酶活性最高,柠条根际土壤蔗糖酶和脱氢酶活性最高;毛刺的盛花期和果实期根际土壤中酶活性普遍较低。不同灌丛各发育期根际土壤微生物群落代谢多样性大多存在显著差异。4种灌丛根际土壤平均颜色变化率(average well color development, AWCD)均随培养时间的延长而逐渐增加,碳源利用类型主要为碳水化合物、氨基酸和羧酸。柠条营养期根际土壤中微生物分布较均匀,代谢活性强,生长旺盛。主成分分析(principal component analysis, PCA)显示,营养期沙冬青、毛刺和猫头刺根际土壤微生物的碳源利用模式相似;盛花期柠条、沙冬青和猫头刺根际土壤微生物的碳源利用模式相似;果实期柠条和沙冬青、毛刺和猫头刺根际土壤微生物的碳源利用模式相似。随着发育期的变化,土壤微生物碳源利用模式发生不同程度的变化。冗余分析(redundancy analysis, RDA)显示,酶活性和微生物代谢功能与土壤理化性质关系密切。脲酶与铵态氮(NH4+-N)正相关;碱性磷酸酶与土壤含水量(SWC)显著正相关;蔗糖酶与全氮(TN)、铵态氮(NH4+-N)、土壤有机质(SOM)和全磷(TP)正相关,且与TN显著正相关;TN、有效磷(AP)、TP、速效钾(AK)和亚硝态氮(NO2--N)显著影响脱氢酶活性。NH4+-N、NO2--N、TP、AP和NO3--N是影响微生物代谢多样性的主要理化因子。该研究结果对于了解宁夏荒漠根际土壤微环境以及微生物群落对环境响应特征具有积极意义。

关键词: 豆科灌丛, 土壤酶活性, Biolog法, 碳源利用, 代谢多样性

Abstract:

This research investigated the enzyme activity and microbial metabolic diversity of desert shrub rhizosphere soil for ecological restoration of desert soil. Four selected legume shrub species (Caragana spp., Ammopiptanthus mongolicusCaragana tibetica and Oxytropis aciphylla) within the Baijitan desert steppe in Ningxia were investigated using visible wavelength spectrophotometry and Biolog microplates, to determine if rhizosphere soil enzyme activity differed in different seasonal development periods (early season ‘nutritional’, flowering, and fruiting periods) and to determine the functional diversity of microbial metabolism. Significant differences in the enzyme activity of rhizosphere soil in the different seasonal phases of shrub growth were detected. In terms of different development periods, the rhizosphere soil urease activity of A. mongolicus was significantly higher than the other three shrubs, and the rhizosphere soil alkaline phosphatase activity of C. tibetica was significantly lower than the other shrubs. For the different development periods, during the nutritional period, rhizosphere soil urease and alkaline phosphatase activity of A. mongolicus were significantly higher than those of other periods, and rhizosphere soil urease and sucrase activity of the unidentified Caragana spp. were significantly lower than those of other periods. During the flowering period, rhizosphere soil urease and alkaline phosphatase activities ofthe Caragana spp., soil sucrase activity of A. mongolicus, and soil urease and dehydrogenase activities of O. aciphylla were significantly higher than at other periods. In the fruiting period, rhizosphere soil urease and alkaline phosphatase activities were highest in A. mongolicus and soil sucrase and dehydrogenase activities were highest in Caragana spp. Enzyme activities were generally low in the rhizosphere soils of C. tibetica during the flowering and fruiting periods. There were significant differences in the metabolic diversity of rhizosphere soil microbial communities in the different seasonal periods. Average well color development of the rhizosphere soil of the four shrub species increased gradually with the duration of incubation time, and the carbon sources utilization were mainly carbohydrates, amino acids and carboxylic acids. The microorganisms in the rhizosphere soil of the Caragana spp. had uniform distribution, strong metabolic activity and vigorous growth during the nutritional period. Principal component analysis showed that in the nutritional period, the carbon source utilization patterns of rhizosphere soil microorganisms were similar in A. mongolicusC. tibetica and O. aciphylla; in the flowering period the patterns were similar in the Caragana spp., A. mongolicus and O. aciphylla; in the fruiting period the patterns were similar in the Caragana spp. and A. mongolicus, and the patterns were similar in the C. tibetica and O. aciphylla. The soil microbial carbon source utilization pattern changed to different degrees through the three seasonal development periods. Redundancy analysis showed that enzyme activity and microbial metabolism were closely related to soil physicochemical properties. Urease was positively correlated with rhizosphere ammonium nitrogen (NH4+-N) level. Alkaline phosphatase activity was significantly positively correlated with soil water content. Sucrase was positively correlated with total nitrogen (TN), NH4+-N, soil organic matter and total phosphorus (TP) (TN were also significantly positively correlated). Also, TN, available phosphorus (AP), TP, available potassium, and nitrite nitrogen (NO2--N) significantly affected dehydrogenase activity. NH4+-N, NO2--N, TP, AP and nitrate nitrogen were the main physicochemical factors affecting microbial metabolic diversity. The results of this study provide insight to and understanding of the rhizosphere soil microenvironment and the rhizosphere microbial community response characteristics to the soil environment in Ningxia desert steppe.

Key words: legume shrub, soil enzyme activity, Biolog method, carbon source utilization, metabolic diversity