苹果开心形树冠不同部位光合与蒸腾能力的研究

 以18年生开心形富士苹果(Malus pumila Mill. ‘Red Fuji’) 为试材, 定点测定了冠层不同部位晴天时的光照分布、气孔导度、光合速率和蒸腾速率。结果表明, 树冠外围的光照强度、单叶光合能力比较高, 内膛、中部和外围叶片最大光合速率分别为13.46、14.69和15.98μmol·m^{- 2} ·s^{- 1}。气孔导度、光合速率和水分利用效率的日变化呈双峰曲线, 而蒸腾速率呈单峰曲线, 在中午外围叶片的蒸腾速率略有降低。内膛、中部和外围叶片在晴天的平均光合速率分别为4.53、6.63和6.54μmol·m^{- 2} ·s^{- 1} , 平均蒸腾速率分别为3.36、4.06和4.40μmol·m^{- 2} ·s^{- 1}。这说明苹果在冠层不同部位的光合与蒸腾能力存在一定的差别, 冠层中部的光合速率和水分利用效率最大, 外围的蒸腾能力最强, 内膛最差。

The Different Ability of Photosynthesis and Transpiration in Different Canopy Positions of Apple with Open-center System

It is very important for trimming, fruit bearing, and accurate irrigation with the study of canopy photosynthesis and transpiration dynamic to fruit tree. So that we studied the ‘Fuji’apple (Malus pumila Mill. ‘Red Fuji’) canopy photosynthesis and transpiration rate in different positions from 2002 - 2004 in‘Richuan’orchard ( longitude 116°13′east, latitude 40°13′north) which training as an open-center system. It had been measured of radiation distribution, the diurnal course of stomatal conductance, photosynthesis andtranspiration rate with random sampling in different positions of canopy. It was found that the radiation flux in exterior was bigger than interior and midst positions, and the ability of photosynthesis of single leaf was so on. The maximal photosynthesis rate of interior, midst positions and exterior leaves were 13.46, 14.69 and 15.98 μmol·m^{- 2} ·s^{- 1}. The diurnal course of stomatal conductance, photosynthesis, WUE (water use efficiency) had two peaks in clear day. And exterior leaves had bigger fluctuate than other. Transpiration diurnal course had one peak, which was decrease in noon. The photosynthesis rate of interior, midst position and exterior leaves in clear day were 4.53, 6.63 and 6.54 μmol·m^-2 ·s^-1 , and transpiration rate were 3.36, 4.06 and 4.40 μmol·m^{- 2} ·s^{- 1}. There were some differences in different positions in canopy of the ability to photosynthesis and transpiration. The value of photosynthesis and WUE in midst position was the most. And the value of transpiration rate in exterior was the most, but interior was the least.