The Effects of Cotyledon Excision on Growth and Leaf Senescence in Soya-bean Plants

One effect of the removal of cotyledons of soya-beans 24 h afterimbibition was to reduce subsequent growth, especially in thefirst 10 weeks after planting. The longevity of treated plantswas increased by 30 days and the onset of leaf senescence delayed,as judged by the time-course of leaf chlorophyll and solubleprotein content, and also by the time-course of net photosynthesisand respiration rates. These effects are similar to those reportedto result from partial defoliation of more mature plants.