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为深入了解农作物根系分泌物与其根际土中可溶有机物的关系,用柱色层族组成分离方法,对小麦和苜蓿根际土中的有机物采用了气相色谱-质谱联用(GC-MS)分析测定。对分离出的极性和弱极性馏分分析结果表明:种植不同农作物的土壤中生物标志化合物分布特征差异很大。小麦根际土壤中主要分布的是C10-C32脂肪酸;苜蓿根际土壤中主要分布的是C10-C30脂肪酸;小麦根际土壤中活性物质十六烯酸、亚油酸和顺反油酸等不饱和脂肪酸在苜蓿上未检出;小麦根际土壤中有机质演化程度及降解程度均大于苜蓿根际土壤。在低演化状况下,根际土中生物标志化合物的分布特征能够很好地反映根系分泌物的特点。芳烃的甲基菲指数MPI值是判识土壤有机质演化和降解程度的良好参数。
In order to further understand the relationship between crop root exudates and soluble organic matter in rhizosphere soil, GC-MS (GC-MS) was applied to the organic compounds in wheat and alfalfa rhizosphere soil by column chromatography. Analytical determination. Analysis of the isolated polar and weak polar fractions showed that the distribution characteristics of biomarkers in soils planted with different crops differed significantly. C10-C32 fatty acids were mainly distributed in rhizosphere soil of wheat; C10-C30 fatty acids were mainly distributed in rhizosphere soil of alfalfa; unsaturated fatty acids such as hexaenoic acid, linoleic acid and cis-elaidic acid in wheat rhizosphere soil Fatty acids were not detected in alfalfa; the extent and degree of degradation of organic matter in wheat rhizosphere soil were greater than those in alfalfa rhizosphere soil. Under low evolutionary conditions, the distribution characteristics of biomarkers in rhizosphere soil can well reflect the characteristics of root exudates. The methylphenanthrene index MPI value of aromatics is a good parameter to judge the evolution and degradation of soil organic matter.