Abstract:

Effects of plastic greenhouse cultivation on photosynthetic characteristics of ‘Cuiguan’ pear were studied. The results showed that there was no significant difference in photosynthetic characteristic of ‘Cuiguan’ pear between the plastic greenhouse cultivation and open field cultivation，and the difference in net photosynthetic rate （Pn） measured at the same time between the two cultivation patterns was related to the leaf age. The light response curves were similar and the light saturation point was about 800 μmol·m^-2·s^-1 under the both cultivation patterns. The diurnal variations of Pn and transpiration rate（Tr） of the pear leaves showed single-peak curves. The significant positive correlation was found between Pn and leaf temperature（Tleaf） and the significant negative correction was observed between Pn and relative humidity（RH） during the developing growth phase under the plastic greenhouse cultivation. The two most important ways regulating pear growth and development inside plastic greenhouse were keeping warm and reducing the humidity. Furthermore，improving photosynthesis of the whole pear plant was an important technique under plastic greenhouse cultivation.

Key words: plastic greenhouse cultivation, ‘Cuiguan’, pear, photosynthetic characteristic