Studies on the leaf photosynthetic characteristics of summer-sown corn duration the course of the growth and development

The leaf photosynthetic characteristics of 5 corn hybrids was studied. The results showed that the pattern of the course of dynamic changes of the chlorophyll content and the soluble protein content of leaves at different position was approximately the same, their maximum values appeared after the leaves full expansion, then gradually decreased, rapidly decreased when the leaves were getting old, but the photosynthetic rates of leaves at different position reached the maximum values at leaves full expansion. Durimg the last phase of growth and development of the com plant, the soluble protein content of the 15 leaf and the photosynathetic rates of the 18 leaf were higher values than others.