Studies on nitrogen fixation by machete resistant mutant strains of azospirillum brasilense their associative nitrogen fixation and yield response of rice oryza sativa to root inoculation in calcareous soil

Rai, R.

Journal of General and Applied Microbiology 31(1): 1-16

1985


ISSN/ISBN: 0022-1260
Accession: 006510130

Download citation:  
Text
  |  
BibTeX
  |  
RIS

Article/Abstract emailed within 1 workday
Payments are secure & encrypted
Powered by Stripe
Powered by PayPal

Abstract
A. brasilense was treated with nitrosoguanidine and 5 machete resistant mutant strains were isolated. The effect of machete on growth, N2-fixation, cell constituents, hydrogenase activity, nitrogenase activity, glutamine synthetase and nitrate reductase activities were studied. Mutant strains MHT 3 and MHT 5 showed lesser nitrate uptake and exhibited greater growth, hydrogenase activity (H2 uptake), G.S. activity and N2ase activity in N-free medium than parental and other mutant strains at 30.degree. C compared with 42.degree. C. Inoculation of rice with A. brasilense and mutant strains led to a significant increase in nitrogenase activity and grain yield compared with the uninoculated control with and without machete (handweeded). Differential response of strains was noted on the N contents of plants and seeds with significant strains .times. genotype interaction. These mutants were stable and retained their resistance even after several subcultures through medium free of machete.