耐酸苜蓿根瘤菌在酸性黄壤中的定殖研究

在酸性黄壤中接种3株耐酸苜蓿根瘤菌91522，91512，91532，并施用不同浓度的Ca^2＋，比较研究了其在苜蓿根际土壤中的定殖动态与水平，进而分析了施Ca^2＋和接种耐酸苜蓿根瘤菌对紫花苜蓿共生效应的影响。结果表明：接种3种耐酸苜蓿根瘤菌均能在酸性土中定殖，且定殖动态基本一致，以接种菌株91512和91532的效果最好。施Ca处理对根瘤菌定殖影响不明显，施5mmol／LCa^2＋时，定殖效果最佳．接种耐酸苜蓿根瘤菌对苜蓿植株瘤重、根鲜重、株高、植株上部鲜重、全氯含量的影响显著.施Ca^2＋对植株根鲜重、株高和上部鲜重的影响达到了极显著水平，对瘤重的影响显著施用5mmol／LCa^2＋，苜蓿生长和结瘤的效果最好，表明在酸性黄壤中，施用适当浓度的Ca^2＋可以提高紫花苜蓿的产量和品质.

DYNAMICS OF ROOT COLONIZATION OF ACID-TOLERANT RHIZOBIUM MELILOTI STRAINS IN AN ACID YELLOW SOIL

Three acid-tolerant strains of Rhizobium meliloti, 91522,91512 and 91532,were used to inoculate the rhizosphere of alfalfa on an acid yellow soil and calcium at different concentration was applied.All the 3 strains of R.meliloti colonized well in the soil and their colonization dynamics was similar.The effect of 91512 and 91532 inoculation was better than that of 91522.Ca application had little effect of R.meliloti colonization.Of the Ca concentrations used in the study,Ca~(2+) at 5 mmol/L gave the best result.Inoculation of the acid-tolerant R.meliloti strains significantly affected nodule weight per plant,root fresh weight,plant height,shoot fresh weight,total nitrogen and rhizobium colonization in the acid soil.Ca~(2+) application showed significant effects on root fresh weight,plant height,shoot fresh weight and nodule weight.It is thus concluded that moderate rate of Ca~(2+) application can improve the yield and quality of alfalfa on acid yellow soil.