不同类型梨品种光合特性的比较

Studies on photosynthesis characteristics of different types of pear cultivars

用CIRAS-1便携式光合作用测定系统测定了5种类型不同梨品种的光合速率和光合作用日变化规律,结果表明,不同类型梨品种的净光合速率(Pn)不同,黄冠(白梨与砂梨的杂交品种)和清香(砂梨品种)的Pn高于红巴梨(西洋梨品种),新鸭梨(白梨品种)和库尔勒香梨(新疆梨品种)的Pn居中。清香和新鸭梨的水分利用率(WUE)高于红巴梨。梨品种的Pn日变化曲线有单峰型和双峰型2类,黄冠及新鸭梨呈单峰型,清香、库尔勒香梨和红巴梨为双峰型。"光合午休"主要为非气孔性限制。不同类型梨品种的蒸腾速率(Tr)日变化曲线率均呈单峰型,细胞间隙CO2含量(Ci)日变化曲线有单谷型和双谷型,气孔导度(Gs)日变化曲线有多种类型,WUE日变化曲线均呈单谷型,气孔阻止值(SLR)日变化曲线呈单峰型或双峰型。

The net photosynthetic rate （Pn） and the diurnal variation curves of photosynthesis of 5 different types of pear cultivars were measured by portable photosynthesis system CIRAS-1. The results showed that the Pn was different among these different types of pear cuhivars ; Pn of Huangguan （Pyrus bretschneideri RehderxP. pyrifolia Nakai） and Qingxiang （P. pyrifolia Nakai） were higher than that of Red Bartlett （P. communis L.）, and the Pn of Xinyali （P. bretschneideri Rehder） and Korla＇s Xiangli （P. sikiangensis Yu） were in the middle of them. The water use efficiency （WUE） of Qingxiang and Xinyali were higher than that of Red Bartlett. The diurnal variation curves of Pn among different types of pear cuhivars were different, which showed two types, single-apex curve and double-apex curve. The diurnal variation curves of Pn of Huangguan and Xinyali presented single-apex ones, and those of Qingxiang, Korla＇ s Xiangli and Red Bartlett presented double-apex ones. The photosynthesis siesta was caused mostly by non-stomatal limitation in Qingxiang, Red Bartlett and Korla＇s Xiangli. The diurnal variation curves of transpiration rate （Tr） among these pear cuhivars presented single-apex curves. The diurnal variation curves of the intercellular CO2 concentration （Ci） presented single-valley and double-valley ones. The diurnal variation curves of the stomatal conductance （Gs） presented many types. Those of the water use efficiency （WUE） presented single-valley ones and those of the stoma limit ratio （SLR） presented single-apex or double-apex ones.