失水胁迫下辣椒幼苗离体叶片光合作用对弱光的响应

 以弱光耐受性不同的4个辣椒（Capsicum annuum L.）自交系为试材，在人工气候室的受控环境中研究叶片短期离体失水胁迫条件下光合作用对弱光（75～100 μmol·m-2·s-1）的响应。结果表明，对于正常光照或弱光环境下的辣椒幼苗，在轻度和中度水分胁迫下，气孔限制因素是引起叶片光合速率下降的主要因素，而严重的水分胁迫使光合速率大幅度下降则是受非气孔因素的限制。在轻度和中度水分胁迫时，辣椒叶片光合作用对弱光的响应较迟缓，即弱光下光合速率随叶片相对含水量（RLWC）减小而下降的趋势相对缓慢，光合速率对水分的变化不敏感。失水胁迫下辣椒（果实味辣）对弱光的适应性强于甜椒（果实味甜）。弱光环境下生长的辣椒叶片水势较高，水合补偿点有减小的趋势。

Response of Photosynthesis in Detached Leaf of Capsicum Seedlings to Low Light under Water Loss Stress

Four capsicum inbred lines were used to study the response of photosynthesis in detached leaves from seedlings to low light under water loss stress in a phytotron. The results showed there was a close relationship between photosynthesis and water conditions under normal or low light. Capsicum seedlings expressed stomatal limitation to photosynthesis under both mild and middle water stresses. However, the decrease of Pn was considered as a result of non-stomata restriction under severe water stress. The response of photosynthesis to low light was slow, i.e. as the decrease of the relative leaf water content (RLWC), the Pn of leaves under low light declined slowly, and photosynthesis was not sensitive to the changes of water. The tolerant capability of photosynthesis to low light under water loss stress in hot pepper was stronger than that in sweet pepper. The leaf water potential of capsicum young plants grown under low light environment was relatively high but the water compensation point showed a declined trend.