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The Effects of Calcium and the Ionophore A23I87 on Modulation, Nitrogen Fixation and Growth of Soybeans
Author(s) -
BLEVINS DALE G.,
BARNETT NEAL M.,
BOTTINO PAUL J.
Publication year - 1977
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1977.tb04876.x
Subject(s) - ionophore , calcium , nitrogen fixation , acetylene , dry weight , rhizobium , leghemoglobin , nitrogen , biology , chemistry , inoculation , zoology , botany , horticulture , root nodule , organic chemistry
The calcium ionophore A23187 was used to separate the processes of infection and nodule development from nitrogen fixation in soybeans. Seedlings of Glycine max (L.) Merr. cv. Williams were grown in solution cultures containing three concentrations of Ca 2+ (0.1, 0.5 or 1.0 m M ) with or without 0.5 μ M ionophore A23187. Three weeks after inoculation with Rhizobium japonicum , strain B1. plants were harvested. Low Ca 2+ (0.1 m M ) significantly reduced nodule number and weight, acetylene reduction, fresh weight of roots and shoots and increased lengths of 2nd and 3rd internodes. There were no significant differences between 0.5 and 1.0 m M Ca 2 in their influence on any parameters measured, except for Ca 2+ concentration in the tissue. The ionophore A23187 significantly reduced nodule number and weight, and increased internode lengths, but it had no effect on acetylene reduction or fresh weight of roots and tops. The ionophore did not affect the Ca 2+ concentration of roots, tops or nodules. Therefore, nitrogen fixation rate is partially independent of number and weight of nodules. The single most important result of this study is that the ionophore A23187 affected critical steps in the infection process or nodule development without influencing subsequent nitrogen fixation.