亚热带季风阔叶林不同林地几种植物光合作用的比较研究

比较了亚热带季风阔叶林不同林地几种植物的叶特性、叶含氮量、叶绿素含量、光合速率和气孔对CO_2的传导率,表明疏林的桃金娘(Rhodomyrtus tomentoso)和荷树(Schima superba)的叶厚和栅栏组织厚度较九节(Psychotria rubra)小,但单位面积干重较九节大,叶含氮量(N mg/g干重)较密林的罗伞(Ardisia quinquegona)低,疏林的桃金娘和荷树的光合作用饱和光强为600和550 μmol 光量子m~(-2),S~(-1),光补偿点分别为12和20 μmol,光量子m~(-2),s~(-1),两种植物的平均最大光合速率分别为11.9±0.4和7.5±1.8 μol CO_2,m~(-2),S~(-1),光合量子产率分别为0.056和0.048,而密林的罗伞光合速率变化对光强变化反应敏感,暗呼吸速率较低。光补偿点为5μmol,光量子m~(-2),S~(-1),显著低于疏林植物,疏林植物有着较高的Ci/Ca值和水分利用效率。亚热带季风阔叶林的不同林地的植物有着不同的光合作用特性,这可能与植物生境的光状况有关。

COMPARATIVE PHOTOSYNTHESIS OF PLANTS GROWN IN VARIOUS SITES OF SUBTROPICAL MONSOON BROAD-LEAVED FOREST

Leaf characteristics, leaf nitrogen content, chlorophyll content, photo-synthetic rate and leaf conductance in plants grown at various sites have been studied. The thicknesses of leaf and palisade tissue of Psychotria rubra grown in the medi-closed site were greater than that of Rhodomyrtus tomentose in opened site. Nitrogen content ( mg N/g DW ) of Ardisia quinquegona in closed site was greater than that of Schima superba in opened site. Light compensation in leaves of Rhod-omyrtus tomentose and Schima superba in higher light environment were 12 and 20 μmol.m-2.s-1, respectively. And the mean maximum photosynthetic rates were 11.9±0.4 and 7.5±1.8μmol.m-2.s-1 for these plants, respectively. But light compensation for leaves of Ardisia quinquegona in closed site was 5 μmol.m-2.s-1 and photosynthetic rate was 3.18±1.90μmol.-2.s-1 for Ardisia quinquogona, light-saturated photosynthesis occurred at 200μmol.m-2.s-1, which was lower than that was happened in Rhodomyrtus tomentose in medi-closed site.The species in opened site had higher steady-value of Ci/Ca and water use efficiency whereas lower Ci/Ca and water use efficiency were found in species in closed site. The results showed that the intrinsic defferent effects of light on photosynthesis might be involved in the light environment of their habitats.