Catalase Is Not Involved in Control of Germination of Cocklebur Seeds

Abstract

Treatment of unimbibed, dry non-dormant upper seeds of Xanthium pensylvanicum Wallr, with KCN, NH₂OH, NaNO₃ or CS(NH₂)₂, at optimal concentration for stimulating germination, inhibited catalase activity in extracts from treated seeds. KNO₃ was also inhibitory to catalase, although ineffective in stimulating germination. Catalase inhibition by these chemicals, except NaN₃, was not observed in seeds presoaked for 7 days, although the seeds were still responsive in germmation. NaN₃-treated seeds showed lowered catalase activity even at the secondary dormancy stage, although NaN₃ failed to cause germination; CS(NH₂)₂, however, elicited higher catalase activity at the secondary dormancy stage. Oxygen enrichment, application of ethylene, anaerobiosis, and chilling, which were very effective in stimulating germination, gave conflicting results in regulating catalase activity. Thus, evidence does not favor a role for catalase in the control of cocklebur seed germination.