Thermoperiodism Mechanism in the Germination of Cocklebur Seeds

Publisher Website
Google Scholar
Abstract
In thermoperiodic germination of secondarily dormant cocklebur (Xanthium pennsylvanicum Wallr.) seeds, the extent of electron flow through the CN-sensitive, cytochrome path and the CN-resistant, alternative path differred in the cool and warm phases. The cool phase triggered active engagement of the alternative path during the subsequent warm phase, and this led to an increase in the ratio of the alternative path flux to the cytochrome path flux. The cool and warm phases had different functions in adenylate metabolism. The former acted mainly in the production and accumulation of ATP, whereas the latter supplied ADP and, especially, AMP. Thus an increasing number of sequential thermoperiodic cycles augmented the size of the adenylate pool and the energy charge, both of which may be necessary for germination to take place.