遮阴及复光对花果期番茄叶片光合特性的影响

以无限生长型番茄“粉冠”为试材，在花果期于日光温室上加盖遮阳网的方式进行为期3d（T1）、6d（T2）、9d（T3）、12d（T4）和15d（T5）的遮阴处理，遮阴结束立即恢复自然光照，以日光温室内自然光为对照（CK）；分别于遮阴结束时和恢复光照第3、6、9、12、15天观测番茄叶片的光合参数，分析其在遮阴条件下的变化特点及复光后的恢复能力。结果表明：与对照相比，遮阴使番茄叶片的光饱和点降低，光补偿点升高。遮阴15d后番茄叶片净光合速率下降49.0%，胞间CO2浓度增加68.3%。随着遮阴日数增加，叶片气孔导度和蒸腾速率呈现先上升后下降的趋势，遮阴15d后，分别下降32.9%和1.6%。叶绿素a、叶绿素b和类胡萝卜素含量随着遮阴日数的增加分别上升125.2%、182.6%和115.4%，其中叶绿素b含量变化显著（P＜0.05）。番茄叶片荧光参数中，F0随着遮阴日数的增加而增加，遮阴15d后增加30.9%，ΦPSⅡ、qP和ETR随着遮阴日数的增加而降低，遮阴后分别减少32.1%、29.8%和36.7%。而Fv/Fm对遮阴环境的响应不显著。遮阴日数对叶片不同参数的恢复能力有不同影响，12d以上的遮阴使叶片净光合速率和胞间CO2浓度无法恢复，9d以上的遮阴使叶片叶绿素含量无法恢复，叶绿素a和类胡萝卜素的恢复能力高于叶绿素b。遮阴日数小于9d时，番茄叶片的光合参数及叶绿素含量均能恢复至初始状态。

Effects of Shading and Light Restoration on Photosynthetic Characteristics of Tomato Leaves during Flowering and Fruit Period

In order to reveal the changes of photosynthetic parameters of tomato leaves under different shading days and the recovery ability of leaf photosynthetic parameters after light restoration, the shading and light restoration experiment on potatoes with solar greenhouse was conducted, taking the infinite-growth-typed tomato “Power Corolla (Lycopersicon esculentum?Mill) ” as material, putting tomatoes in greenhouse during the flowering and fruiting period, and 5 different shading days treatments were designed: T1 (3 days shading), T2 (6 days shading), T3 (9 days shading), T4 (12 days shading) and T5 (15 days shading). The natural light in the greenhouse was used as the control (CK). The results showed that shading decreased the light saturation point and increased the light compensation point of tomato leaves comparing with CK. Net photosynthetic rate of tomato leaf after shading 15 days decreased by 49.0%, and intercellular carbon dioxide concentration increased by 68.3%. With shading days growing, stomatal conductance and transpiration rate decreased quickly after a short increasing, which decreased by 32.9% and 1.60% respectively after shading 15 days. The content of chlorophyll a, chlorophyll b and carotenoids increased by 125.2%, 182.6% and 115.4% respectively when the shading days growing, and the change of chlorophyll b content was significant (P<0.05). Among the fluorescence parameters in tomato leaves, F0 increased with shading days growing, and increased by 30.87% after shading 15 days, while ΦPSⅡ, qP and ETR decreased with the shading days growing, and they decreased by 32.4%, 29.8% and 36.7% respectively after shading 15 days. Nonetheless, the response of Fv/Fm to shading environment was not significant. The shading days had different effects on the recovery ability of different leaf parameters, shading more than 12 days made leaf net photosynthetic rate and intercellular carbon dioxide concentration unable to restore to original state. The chlorophyll content in leaves could not be recovered when shading more than 9 days, the recovery capability of chlorophyll a and carotenoids was better than that of the chlorophyll b. When shading period was less than 9 days, the photosynthetic parameters and chlorophyll content of tomato leaves could be restored to the initial state after the recovery process.