Does the embryonic axis affect respiration in pea cotyledons?

The conditions of imbibition crucially affected respiration of the excised pea cotyledons, Pisum sativum L. var. Bördi, during subsequent incubation. When excised cotyledons were immersed in water during imbibition, their respiration rate was lower than that of attached cotyledons up to 96 h of incubation. Hydration of excised cotyledons was faster than that of attached cotyledons, particularly at early stages of imbibition. The dry weight of excised cotyledons, however, decreased more rapidly than that of attached cotyledons. When excised cotyledons were kept on moist filter paper from the onset of imbibition, their respiration rate was the same as that of attached cotyledons during later incubation. In addition, the hydration rate of both excised and attached cotyledons was the same under such conditions, whereas the dry weight of the attached cotyledons decreased more rapidly than those of excised cotyledons. It was concluded that the respiration rate of the excised cotyledons during incubation was only dependent on the conditions used during imbibition. Hence, the embryonic axis had not effect on the development and maintenance of the respiratory activity in the cotyledons of germinating peas.