Effects of Plant Types on Assimilation and Partitioning of 14 C Assimilates within Cotton Plants

Using 14 C tracing technique ,the effects of simplified prunign(top shoot niqqing of main stem and vegetative branches only)and simplified pruning with earlier top shoot nipping on the production and partitioning of 14 C assimilates within cotton plants were studied. It showed that simplified pruning could reduce the 14 C assimilation and rate of photosynthesis in leaves on fruiting branches.And the partitioning of 14 C assimilates in the plant organs 72 hours after labelling that indicated the simplified pruning could decrease the translocation of 14 C assimilates into main stem and fruiting branches in squaring stage and flowering stage. Earlier top shoot nipping of main stem could increase the rate of photosynthesis in leaves on fruiting branches, vegetative branches and the partitioning of 14 C assimilates into vegetative branches in flowering stage. Analysis of yield components of cotton with vegetative branches, the number of bolls on main stem, average weight per boll and lint percent were reduced, but the number of bolls on vegetative branches could make up for a lack of the bolls on main stem. Earlier top shoot nipping of main stem could increase the number of bolls on vegetative branches, average weight per boll and lint percent. There were no remarkable effects on the lint cotton per hectare.