南瓜结果期净光合速率及其影响因子日变化特征

以蜜本南瓜为材料，对其结果期净光合速率及光合有效辐射、温度、空气湿度、大气二氧化碳浓度、蒸腾速率等影响因子进行了研究。蜜本南瓜的净光合速率曲线晴天为双峰型，存在明显的光合“午睡”现象；阴天为单峰型；其影响因子均有明显的日变化特征。晴天中午太阳辐射强，光合有效辐射平均值大，12:00—15:00间的平均值达1246.3?mol/(m2·s)；温度高，12:00—15:00间气温平均值达31.7℃，叶温平均值达37.4℃；空气湿度低，12:00—15:00间空气湿度平均值为，这些因素是引起光合“午睡”的主要环境因素。

Net Photosynthetic Rate of Pumpkin in Fruit-setting Period and the Day Change Character of Effecting Factors

The net photosynthetic rate of Mi-ben Pumpkin and the effecting factors of PAR, temperature, air humidity, and CO2 content and transpiration rate were studied. The net photosynthetic rate was double-peak and exited significant photosynthesis “noon-rest” on sunny day. It was single-peak on cloudy day. The effecting factors had significant day-change Character. The solar radiation was powerful on sunny noon. The average PAR was 1246.3?mol/(m2·s) from 12:00 to 15:00. The temperature was high on sunny noon. The average air temperature was 31.7℃ and the leaf temperature was 37.4℃ from 12:00 to 15:00. The air humidity was low and was 42.3% from 12:00 to 15:00. These factors were main environment factors leading to “photosynthesis noon-rest”.