title: [Effects of Ca2+ on acid tolerance of Medicago sativa and Rhizobium meliloti].
abstract: Soil acidity is an important environmental factor hampering the effective symbiotic nitrogen fixation of Rhizobium meliloti and its host plant Medicag sativa. The study on the effects of Ca2 + on the acid tolerance of M. sativa and R. meliloti showed that applying 5 and 10 mmol . L(-1) of Ca2+ could promote the growth of R. meliloti and advance its log growth phase. Under neutral pH condition, applying Ca2+ didn't have any significant effects on root hair deformation, while under low pH condition, Ca2+ demonstrated positive functions. The higher the Ca2+ concentration, the more significantly it affected, indicating that Ca2+ might play an important role in the recognition between R. meliloti and its host plant. Applying Ca2+ under low pH made the nodulation ahead of time and the nodulation rate enhanced. Definite concentration of Ca2+ could increase the number of nodules in the same period, which was more obvious at anaphase stage or under lower pH condition.
authors.affiliation: College of Resource and Environment, Southwest University, Chongqing 400716, China. jhtabszq@sina.com
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Shi-qing
authors.initials: SQ
authors.lastname: Wei
authors.forename: Yan-bin
authors.initials: YB
authors.lastname: Li
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D000455:Medicago sativa / Q000187:drug effects / Q000382:microbiology / Q000502:physiology*; D053204:Root Nodules, Plant / Q000187:drug effects / Q000382:microbiology / Q000502:physiology; D016962:Sinorhizobium meliloti / Q000187:drug effects / Q000502:physiology*; D012987:Soil / Q000032:analysis*; D013559:Symbiosis
chemical_list: D012987:Soil; D002118:Calcium