The Research On The Photosynthetic Characteristics Of Different Sand Pear Cultivars

In this Paper, the net Photosynthetic rate(Pn)and the diurnal variation curves of PhotoSynthesis of five different tyPes of Pear cultivars were measured by using the LI-6400—Portable Photosynthesis System.The Photosynthesis characteristics under differentcondition and of different types leaves were studied.The results showed that:The Pn of leaves were difference among these different types of Pear cultivars, the Max Pn of Wandaxingaos'leaves was highest among the 7 different kinds.The water use efficiency(WIJE) indicated complicated. The light compensation Point(LCP)and CO₂ compensation Point(CCP)of different types of pear cultivars leavesare were 10 50μmol.m^-2.s^-1 and 40 80μ.mol.mol^-1. And there were no significant difference among these cultivars, however, the LSP and CSP were 1400 1520μmol.m^-2.s^-1 and 900¹400 mol.mol^-1.The carborylation efficiency of leaves were slightly different among the 7 kinds of pears. Wandaxingao had the highest one ,Zaomixingao had the smallest one.The diurnal variation curves of Pn among different types of Pear cultivars were different, and there are two types, single—apex curve and anisomerous double—apex curve. Pear cultivars Presented single—apex curves on apirl and double—apes curves on June.The diurnal variation curves of CiPresent single—valley curves. The diurnal variation curves of Cond Present many types.Comparing different kinds of pears cultivars ,Wadaxingao pear had the max Pn and average Pn. Jinqiu pear had the second position. Other pears cultivars was little difference between each other. Jinqiu pears light compensation Point(LCP) was the lowest while Daguoshuijing was the highest. Zaoshenghuangjin pear had the lowest the Light Saturation Point (LSP), while Daguoshuijing had the highest one. Jinqiu pear' s CO₂ compensation Point(CCP) was the lowest, Zaoshenghuangjin pear was the highest. Wandaxingao pear ' s CO₂ Saturation Point(CSP) was lowest, and Zaoshenghuangjin pear was the highest. Comparing to the AQY among them, Zaomixingao pear was in the lowest level, while Jinqiu pear was in the toppest level. The CE of them, Zaoshenghuangjin was the lowest, while Wandaxingao was the toppest.