9Wilson J W, Hand D W, Hannah M A. Light interception and photosynthetic efficiency in some glasshouse crops[J]. Jour- nal of Experimental Botany, 1992, 43(3): 363-373.
10Yang J C, Peng S B, Visperas R M, et al. Grain filling pattern and cytokinin content in the grains and roots of rice plants[J]. Plant Growth Regulation, 2000, 30(3): 261-270.