The diurnal variation curve of net photosynthetic rate had two peaks under 0% and 15% shading treatments,while there was only one peak under 35%and 50% shading treatments.

• 全光照和遮光15%25处理条件下,Pn日变化呈双峰曲线,而35%25和50%25处理条件下呈单峰曲线;