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The physiological basis of seed dormancy in Avena fatua L. I. Action of the respiratory inhibitors sodium azide and salicylhydroxamic acid
Author(s) -
Upadhyay Mahesh K.,
Naylor James M.,
Simpson Graham M.
Publication year - 1982
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1982.tb00702.x
Subject(s) - salicylhydroxamic acid , germination , sodium azide , gibberellic acid , dormancy , avena fatua , seed dormancy , biology , horticulture , botany , biochemistry , respiration
The dormancy breaking effect of sodium azide was studied in seeds of several genetically pure lines of Avena fatua L. isolated from field populations. Sodium azide (0.8 and 1 m M ) induced germination in several dormant lines (characterized by long term dormancy) after two weeks of treatment. By about five weeks, germination was nearly complete in azide treated seeds as compared to little or no germination in controls. (2‐chloroethyl) trimethylammonium chloride (an inhibitor of gibberellin biosynthesis) completely inhibited the azide effect suggesting that stimulation of germination by azide requires gibberellin biosynthesis. Azide was very effective in breaking dormancy in lines AN‐51, AN‐86, AN‐127 and AN‐265, but failed to induce germination in Montana 73. In this line there was a synergism between azide and gibberellic acid in promotion of germination. Thus, at least two metabolic blocks are involved in the stimulation of germination in this line. Salicylhydroxamic acid (an inhibitor of alternative respiration) at 3 m M completely inhibited the germination induced by 1 m M azide. At this concentration, salicylhydroxamic acid did not inhibit germination in 1) genetically nondormant seeds (line SH‐430), 2) afterripened seeds of a dormant line (AN‐51), and 3) gibberellic acid‐treated dormant seeds. These findings suggest that salicylhydroxamic acid‐sensitive process(es), presumably alternative respiration, is necessary for the stimulation of germination in the presence of azide, but not in the germination of genetically nondormant, gibberellic acid‐treated dormant, or afterripened seeds.