低分子量根系分泌物对土壤微生物活性及团聚体稳定性的影响  

Effects of Soluble Root Exudates on Microbial Activity and Aggregate Stability of Black Soils

作　　者：苑亚茹[1,2] 韩晓增[1] 李禄军[1] 丁雪丽[1] 

机构地区：[1]中国科学院东北地理与农业生态研究所,黑土区农业生态院重点实验室,哈尔滨150081 [2]中国科学院研究生院,北京100049

出　　处：《水土保持学报》2011年第6期96-99,共4页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(40971152);黑龙江省自然科学基金(ZD200904)

摘　　要：以黑土为供试土壤,采用化学试剂模拟根系分泌物进行室内培养试验,研究低分子量根系分泌物及主要组分对土壤微生物活性及团聚体稳定性的影响。结果显示,与对照相比,低分子量根系分泌物及主要组分短期内均显著提高了土壤微生物的活性,促进了>250μm大团聚体,尤其是>2 000μm团聚体的形成,显著增强了土壤团聚体的稳定性。低分子量根系分泌物中葡萄糖组分有利于土壤中细菌的生长,从而在细菌活动的驱动下,促进了微团聚体的形成;苹果酸和谷氨酸组分则有利于真菌的生长和繁殖,在真菌菌丝网络的缠绕和粘结作用下,促使微团聚体进一步胶结形成大团聚体。因此,低分子量根系分泌物中各主要组分共同参与并影响土壤的团聚化过程,改善根际微区土壤的结构,以利于植物根系的生长。A laboratory experiment was carried out to investigate the effect of soluble root exudates on soil microbial activity and aggregate stability of black soils dominated by 2 - 1 clay minerals. Results indicated that, compared with the control, the addition of all substrates caused a sharp increase in microbial activity within a short peroid of time and significantly increased soil aggregate stability and the proportion of macro- aggregates larger than 250 μm, especially those larger than 2 000 μm. Glucose caused a stimulation of soil bacteria, which was accompanied by the formation and stabilization of soil microaggregates and malic acid and glutamic acid induced an increase in soil fungi, which were involved in the formation of soil macroaggregates by producing organic substances that bind soil partcles together into micro- and macroaggregates and enmeshing microag- gregates into macroaggregates. This implies that soil conditions are positively modified by the release of soluble root exudates from living roots into the rhizosphere and this is favorable for the growth of plant roots.

关 键 词：根系分泌物 团聚体稳定性 微生物活性 黑土 

分 类 号：S152.4[农业科学—土壤学] S154.3[农业科学—农业基础科学]