About Us | Help Videos | Contact Us | Subscriptions



This article in CS

  1. Vol. 27 No. 3, p. 548-552
    Received: June 5, 1986



Nitrate Utilization and Dinitrogen Fixation (Acetylene Reduction) by Nitrate Reductase-Defecient Mutants of Pea1

  1. G. T. Vigue and
  2. R. L. Warner2



Three NO3 reductase pea (Pisum sativum L.) mutants and the ‘Juneau’ control were evaluated for the ability to absorb and accumulate NO3 from solution, and for growth and N2 fixation (C2H2 reduction) in the presence and absence of NO3. In short-term (20 h) hydroponic studies, the mutants absorbed NO3 at rates similar to Juneau, but accumulated more NO3 than Juneau in both shoots and roots. Seedlings of Juneau assimilated 63%, while seedlings of mutants assimilated <35% of absorbed NO3. In long-term studies with plants grown in vermiculite in the presence of 15 mM NO3, dry weights of mutants A300 and A317 were <50% of Juneau. However, growth of mutant A334, which had only 6 to 8% of the NO3 reductase activity of Juneau, was equal to the control. Growth of mutant A300 was not as rapid as the other genotypes when N2 fixation or NH+4 was the only N source. All three mutants and Juneau exhibited good levels of C2H2 reduction activity and growth in the absence of mineral N. Also, the NO3 reductase mutations did not lessen the inhibition of N2 fixation by NO3 and the cause of the inhibition remains unclear.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © .