Effects of drought, temperature, and salinity on symbiotic nitrogen fixation in legumes, with emphasis on chickpea and pigeonpea [a review]
1987
Rupela, O.P. | Rao, J.V.D.K.K.
The legume-Rhizobium symbiosis is a highly integrated and, to a considerable degree, self-regulating process. It is particularly sensitive to such environmental influences as drought, salinity, and extremes of temperature, more so than rhizobia growing alone. Although the effect of these factors on the symbiosis has been studied mostly under laboratory conditions, a good understanding has been achieved of how the symbiosis responds to various forms of stress. All three stress factors impair the development of root hairs and the site of entry of rhizobia into the host, resulting in poor nodulation or even absence of nodules. Salinity and high temperature more greatly affect nodulated plants than nitrogen-fertilized plants. Since existing knowledge on the effects of stress factors on symbiotic nitrogen fixation has been derived mostly from studies with legumes other than chickpea or pigeonpea, detailed studies of these effects are needed for these two crops. In addition, because strains of rhizobia tolerant to these stress factors are either available or identifiable by laboratory screening procedures, efforts to identify individual chickpea and pigeonpea genotypes tolerant to these stress factors could help improve the overall tolerance of the symbiosis
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