Abstract: The environment in solar-greenhouses varied much in different seasons. In spring, the internal environment was favourable to the growth of cucumbers, while in winter, the lighting period was shorter and the photo flux density was lower. Under winter conditions, the average net photosynthetic rate (Pn) showed a typical curve with one peak, in comparison with the double peaks under spring conditions. Cucumber functional leaves under different conditions were measured in vivo in order to evaluate the kinetics of 685 chlorophyll fluorescence induction.Results indicated that the M peak in the induction curve that reflected the activity of the assimilation enzyme was less clearer in winter than in spring. It was also found that among different cucumber varieties, the M peak of Changchunmici was the clearest, followed by Nongda 14, while that of Jinza 2 almost could not be seen. In sotar-greenhouses, irradiance affected photosynthesis more than temperature, and the sustained period of suitable temperatrue contributed mostly to photosynthesis. According to the results, the cucumber varieties that were tolerant to low temperature like Nongda-14 might not necessarily tolerate to low irradiance. In winter, the CO₂ concentration in the solar-greenhouse during the day Varied more violently than in spring, so it would be necessary to supplement CO₂ gas.

Key words: Solar-greenhouse, Cucumber, Photosynthesis

CLC Number: 

• S642.201