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为深入研究根系分泌物对根际土中有机物贡献的特点,用柱色层族组成分离方法,对小麦和苜蓿根际土及二者交界地中提出的可溶有机物采用了GC/MS分析测定。从样品的非极性馏分中分析检测出正构烷烃、类异戊二烯烷烃及酯类3个系列的生物标志化合物,并对小麦地、苜蓿地及二者的交界地中的正构烷烃的奇偶优势比(OEP)、∑C22-/∑C23+比值和姥植比(Pr/Ph)进行了分析比较。小麦和苜蓿的GC/MS的主峰均为nC31,正构烷烃奇偶优势比OEP值大小顺序为苜蓿地>交界地>小麦地,且三者数值均>1.4。正构烷烃∑C22-/∑C23+比值大小顺序为小麦地>交界地>苜蓿地。姥植比(Pr/Ph)的比较结果为苜蓿地>交界地>小麦地。这表明小麦和苜蓿根系分泌物进入土壤后演化程度不一样,小麦地有机质演化程度高于苜蓿地。
In order to further study the characteristics of root exudates contributing to organic matter in rhizosphere soil, GC / MS analysis of soluble organic matter in wheat and alfalfa rhizosphere soil and the boundary between them was carried out by using column color layer composition separation method . Three series of biomarkers, n-alkanes, isoprenoids and esters, were detected and detected from the non-polar fractions of the samples. The biomarkers of wheat bran, alfalfa and their n-alkanes The odds ratio (OEP), ΣC22- / ΣC23 + ratio and basal ratio (Pr / Ph) were analyzed and compared. The major peaks of GC / MS of wheat and alfalfa were all nC31, and the order of nadir and nadir of n-alkanes was> 1.4 for alfalfa land> border land> wheat land. N-alkane ΣC22- / ΣC23 + ratio of the order of wheat land> border> alfalfa land. The results of pr / Ph ratio were alfalfa land> border> wheat land. This indicates that the evolution of wheat and alfalfa root exudates into the soil is not the same, the evolution of organic matter in wheat is higher than alfalfa.