早实与晚实核桃光合和荧光特性差异比较研究

Comparison on photosynthetic and fluorescence characteristics between early and late fruiting walnut varieties

【目的】通过比较早实与晚实2个核桃类群的光合和荧光参数差异,分析其对光环境的需求特征,为其在生产条件下的丰产栽培提供科学依据.【方法】以3个早实和3个晚实核桃品种为试材,采用便携式Li-6400光合仪和PAM-2500叶绿素荧光分析仪,在自然条件下测定了光合速率(Net photosynthetic rate,P_n)、气孔导度(Stomatal Conductance,G_s)、胞间CO_2浓度(Intercellular CO_2Concentration,C_i)、水分利用效率(Water Use Efficiency,WUE)、光饱和点(Light Saturation Point,LSP)、光补偿点(Light Compensation Point,LCP)等光合参数和最大光能转化效率(Variable Fluorescence/Maximal Fluorescence,F_v/F_m)、实际光化学效率(Actual Photochemical Efficiency,Yield)、光化学淬灭(Photochemical quenching,qP)、非光化学淬灭(Non-photochemical quenching,qN)等荧光参数,比较了早实与晚实核桃类群的光合和荧光特征差异.【结果】早实与晚实品种出现的光合‘午休’现象均是由非气孔限制因素引起的.光合和荧光参数日变化均值显示,早实品种的P_n、WUE、F_v/F_m、Yield以及qN均高于晚实品种(PP_n<0.05,PWUE<0.05,PYield<0.05,P_qN<0.05),说明早实品种的光合能力高于晚实品种,且对光抑制反应较为敏感,光合机构自我保护能力较强.此外,与早实品种相比,晚实品种的LSP增加了6.71%,LCP减少了2.58%,此参数表明晚实品种对强光的利用能力以及对环境的适应能力强于早实品种,早实品种受到强光照射时更容易发生光抑制.【结论】早实与晚实品种的光合和荧光特征存在差异,早实品种的光合能力高于晚实品种,晚实品种较早实品种有着更强烈的需光性.

【Objective】The light requirement characteristics of early and late fruiting walnut varieties were analyzed by comparing their differences of photosynthetic and fluorescence parameters in order to provide the theoretical basis for the high yield cultivation under the production conditions.【Method】Three early fruiting and three late fruiting walnut cultivars were used as the materials to determine the photosynthetic and fluorescence parameters by using Li-6400 portable photosynthesis system and PAM-2 500 portable chlorophyll fluorescence system.Photosynthetic parameters included net photosynthetic rate(P n),stomatal conductance(G s),intercellular CO 2 concentration(C i),water use efficiency(WUE),light saturation point(LSP),light compensation point(LCP).And fluorescence parameters included maximum photochemical efficiency(F v/F m),actual photochemical efficiency(Yield),photochemical quenching(qP)and non-photochemical quenching(qN).【Result】The photosynthetic'noon break'phenomenon existed both in early and late fruiting varieties was caused by the non-stomatal limitation factors.The average value of diurnal variation of photosynthetic and fluorescence parameters showed that P n,WUE,F v/F m,Yield and qN of early fruiting walnut varieties were higher than those of late fruiting varieties(P P n<0.05,P WUE<0.05,P Yield<0.05,P qN<0.05).It indicated that the photosynthetic capacity of early fruiting varieties was higher than late fruiting varieties,the reaction of light inhibition was more sensitive,and the ability of self-protection of photosynthetic mechanism was strong.Compared with early fruiting varieties,the LSP of late fruiting varieties increased by 6.71%,LCP decreased by 2.58%,this suggested that late fruiting varieties had stronger ability of photosynthesis by using strong light and were more adaptable to the environment.The early fruiting varieties were easy to occur light suppression when exposed to strong light.【Conclusion】The photosynthetic and fluorescence characteristics were different between early and late fruiting varieties.Early fruiting varieties had higher photosynthetic capacity,and the light requirement of late fruiting varieties was greater than early fruiting varieties.