Nitrate and nitrate reductase in Erythrina caffra seeds: Enhancement of induction by anoxia and possible role in germination |
| |
Authors: | Karin Kemp J G Chris Small |
| |
Institution: | (1) Department of Botany and Genetics, University of the Orange Free State, P.O. Box 339, 9300 Bloemfontein, South Africa |
| |
Abstract: | The nitrate level in seed embryonic axes of Erythrina caffra Thunb. which is capable of anaerobic germination, was about 2.5 times higher than in seed axes of Pisum sativum L. a species incapable of anaerobic germination. Nitrate levels in E. caffra seeds decreased during germination and this was not due to leaching. Both NADH- and NADPH-dependent nitrate reductase (NAR) activities increased during germination. The increase was prevented by cycloheximide. The activity of NADH-NAR (EC 1.6.6.1) was higher than that of NADPH-NAR (EC 1.6.6.3). Both NAR activities were higher in anoxia than in air during germination. The NAR activities in Pisum seeds were very much lower than in Erythrina seeds. Anoxia (N2 or argon) enhanced the induction of NAR by KNO3 in germinated E. caffra axes. The NADH- and NADPH-NAR activities were induced to equally high levels by KNO3 under anoxia. The enhancement was depressed by cycloheximide. It is concluded that nitrate and NAR activity may play a role in the anaerobic germination of E. caffra seeds.Abbreviation NAR
nitrate reductase
Financial support was obtained from the University of the Orange Free State and the Foundation for Research Development |
| |
Keywords: | Anoxia Erythrina (anaerobic germination) Germination (anoxic) Nitrate Nitrate reductase Pisum |
本文献已被 SpringerLink 等数据库收录! |