Plant Physiol.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Plant Physiology 63:421-424 (1979)
© 1979 American Society of Plant Biologists

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Web of Science (54)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Franco, A. A.
Right arrow Articles by Neyra, C. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Franco, A. A.
Right arrow Articles by Neyra, C. A.
Agricola
Right arrow Articles by Franco, A. A.
Right arrow Articles by Neyra, C. A.
Articles

Seasonal Patterns of Nitrate Reductase and Nitrogenase Activities in Phaseolus vulgaris L. 1

Alvilio A. Franco, Joao C. Pereira and Carlos A. Neyra2

a Programa de Fixacao Biologica de Nitrogenio (CNpq-EMBRAPA-UFRRJ) Km 47, SEROPEDICA 23460, Rio de Janeiro, Brazil

The patterns of nitrate reductase activity (NRA) in the leaves (in vivo assay) and root nodule nitrogenase activity (C2H2 reduction) were investigated throughout the season in field-grown Phaseolus vulgaris plants.

Maximal NRA (per g fresh weight) occurred at early stages of leaf development but total activity (per leaf) was maximal when the leaf reached full size. In mature plants, most NRA was associated with the upper leaves. Nitrogenase activity was initiated about 2 weeks after sowing, reached a maximum at flowering (5 weeks after sowing) and declined rapidly thereafter. Nitrogenase activity followed the pattern of nodule development. After flowering, P. vulgaris was apparently able to take up and assimilate NO–3 as evidenced by the increase in NO–3 content of the stem and the high levels of NRA in the leaves. Total plant NRA was maximal after flowering and addition of NH4NO3 to the soil at flowering resulted in even higher levels of NRA through most of the pod-filling period, thus resulting in higher seed yields (59% over control).

It is proposed that P. vulgaris can benefit from both N2 fixation and NO–3 assimilation and that nitrate reductase plays an important role in the assimilation of nitrogen after flowering.

2 Present address: Biochemistry and Microbiology Department, Cook College-Rutgers University, New Brunswick, New Jersey 08903.

1 A preliminary report of this work was given at the annual meeting of the Society of Plant Physiologists in Madison, Wisconsin, 1977.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 1979 by the American Society of Plant Biologists