Abstract:

This paper mainly deals with the changes of the rate of net photosynthesis (P_n) which varied with leaf age, including primordial leaf of seedlings and 1 or 2-year-old needles of young trees of Pinus massoniana. The habitat, productive structure and the variation of net photosynthesis and net primary productivity were also studied of the groves which were formed by natural regeneration. The research results showed that peak value of P_n occurred during July for primordial leaves and the rate of P_n varied in a biparabolic curve for 1 or 2-year-old needles. In order to improve the net primary productivity of the natural stands of this species, the productive structure of the groves should be properly controlled.

Key words: Masson's pine, Leaf age, Net photosynthetic rate