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作 者 ：孙谷畴

期 刊 ：武汉植物学研究 1987年 5卷 2期 页码：165-172

关键词：荔枝；光合速率；光；CO2和叶片/空气水蒸汽压陡度；

Keywords:Litchichinensis, Photosyntheticrate, Light, CO2andleaf/airwatervaporgradient,

摘 要 ：在低光强(0至0.15m mol m^-2s^-1)下,荔枝叶子的光合速率随光入射量子通量的增高而增大。在光强0.7m mol m^-2s^-1时光合速率为1.76μmol m^-2s^-1。光合作用的光补偿点约为0.02 m mol m^-2s^-1光量子。荔技叶子具有低的气孔对水分传导率。气孔对水分传导率和蒸腾速率在低光强时随入射量子通量增高而增大:而细胞间CO₂浓度随光强增高而下降。在光强高于0.2m mol m^-2 s^-1光量子时,细胞间CO₂浓度变化较少。在低光强时,叶子的水分利用效率（光合/蒸腾）随光强增高而增大。在光强高于0.2m mol m^-2 s^-1光量子时,水分利用效率明显降低。荔枝叶子的最适光合作用叶温为22-26℃。可能表明在华南夏季中午的高温限制荔枝的田间光合作用。外界CO₂浓度增高相应增高细胞间CO₂浓度。当细胞间CO₂浓度约低于230μ1.1^-1时,光合速率随细胞间CO₂浓度增高而增大。在更高的细胞间CO₂浓度对,光合速率变化则较少。荔枝叶子光合速率对叶子/空气水蒸汽压陡度的变化响应不敏感。气孔对水分传导率和细胞间CO₂浓度随叶子/空气水蒸汽压陡度增大略有降低。

Abstract:Plants of Litchi chinensis were grown under greenhouse conditions that were controlled to mimic natural environmental condition. Net photosynthesis increased with increasing incident quantum flux from 0 to 0.15 m mol m^-2s^-1, PN=10.32p+0.14. Photosynthetic light compensation point occurred at 0.02 m mol m^-2s^-1 photon and photosynthesis rate of 1.76 μ mol m^-2s^-1 was measured at irradience of 0.7 m mol m^-2s^-1 photon. Leaf conductance to water vapor and transpiration also increased as the incident quantum flux increased from 0 to 0.15 m mol m^-2s^-1 photon.Litchi leaves were not so much sensitive to change in the leaf to air water vapor gradient. In this humidity range, leaf conductance decreased slightly, G=-0.28⊿W+35.2.Net photosynthesis increased as intercellular CO₂ concentration increased from 0 to 230 μ1 1^-1and the projected CO₂ compensation point was approximately 38.5μ1 1^-1.There was a small dependence of net photosynthesis on leaf temperature beween 22 to 6℃. Photosynthetic rate decreased rapidly at the temperature above 30℃.These results suggest that lower net photosynthesis may be alimited factor of the growth of plant and under natural field condition photosynthesis in leaves of Litchi is likely to be reduced by high temperature that commonly occure during midday periods in summer.

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