喀斯特生境3种经济林树种光合作用对光强的响应特征

Response characteristics of photosynthesis to light intensity of three non-wood forests tree species in karst habitat

  • 摘要: 【目的】分析喀斯特生境3种经济林树种叶片对光强的光合生理响应,为喀斯特石漠化区生态修复植物选种育种提供理论依据。【方法】使用Li-6800便携式光合作用测定仪测定相同生境条件下花椒(Zanthoxylum bungeanum)、枇杷(Eriobotrya japonica)与核桃(Juglans regia)的光合作用—光响应和叶绿素荧光响应特征及暗下荧光参数,采用SPSS 25.0对光响应拟合参数进行单因素方差分析,比较喀斯特高原峡谷不同经济林树种的光合能力。【结果】核桃叶片的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和电子传递速率(ETR)光响应曲线与枇杷和花椒叶片差异显著(P<0.05,下同),均先呈大幅上升,后趋于平稳,枇杷和花椒光响应曲线的上升幅度则显著高于核桃,且枇杷叶片在高光强下仍有上升趋势;三者的胞间CO2浓度(Ci)、气孔限制值(Ls)与水分利用效率(WUE)对光强的响应差异不显著(P>0.05),总体上升/下降幅度排序为花椒>枇杷>核桃。3种经济林的最大净光合速率(Pnmax)为2.89~8.80 μmol/(m2·s),表观量子效率(AQY)为0.055~0.067 μmol/(m2·s),光饱和点(LSP)为866.06~2283.86 μmol/(m2·s),光补偿点(LCP)为13.29~49.90 μmol/(m2·s),花椒的光合性能最好,而枇杷的光合潜力最高。核桃叶片初始荧光(Fo)、最大荧光(Fm)及PSII光化学效率(Fv/Fm)均显著低于枇杷和花椒。【结论】枇杷和花椒的光合生理特性对光强表现出明显的响应,花椒光合能力最强,而枇杷生态适应性最好,在未来的种植中可考虑增加枇杷的土壤养分,以增加枇杷的光合能力,进而提高植物生产力;核桃易发生光抑制,建议在最大光强较低的地区种植。综上所述,花椒和枇杷更适宜做喀斯特高原峡谷地区石漠化治理的经济树种。

     

    Abstract: 【Objective】 The photosynthetic physiological responses of leaves of three non-wood forests tree species in karst habitat to light intensity were analyzed to provide theoretical basis for selection and breeding of ecological restoration plants in the karst rocky desertification area.【Method】 Used the Li-6800 portable photosynthesis meter to determine the photosynthesis-light response and chlorophyⅡ fluorescence response characteristics of Zanthoxylum bungeanum, Eriobotrya japonica and Juglans regia under the same habitat conditions,as well as the dark fluorescence parameters,One-way ANOVA using SPSS 25.0 for the light response fitting parameters,and then compared the differences in karst plateau valley photosynthetic capacity of non-wood forests tree species.【Result】 The net photosynthetic rate(Pn),transpiration rate (Tr), stomatal conductance (Gs), and electron transfer rate (ETR)light response curves of J. regia leaves were significantly different from those of E. japonica and Z. bungeanum leaves to light intensity(P<0.05, the same below),they all rose sharply at first,and then tended to be stable. The curve of E. japonica and Z. bungeanum rose significantly higher than J. regia,while E. japonica leaves still had a rising trend under high light intensity;the intercellular CO2 concentration (Ci), stomatal limit value(Ls)and water use efficiency(WUE)of the three had no significant difference to light intensity (P>0.05),and the overall increase/decrease range was Z. bungeanum>E. japonica>J. regia. The maximum net photosynthetic rate(Pnmax)of the three non-wood forests was 2.89-8.80 μmol/(m2·s),and the apparent quantum efficiency(AQY) was 0.055 to 0.067 μmol/(m2·s). The light saturation point(LSP)was 866.06-2283.86 μmol/(m2·s),and the light compensation point(LCP)was 13.29-49.90 μmol/(m2·s). The photosynthetic performance of Z. bungeanum was the best, while E. japonica had the highest photosynthetic potential. The initial fluorescence(Fo),maximum fluorescence(Fm), and PSII photochemical efficiency(Fv/Fm)of J. regia leaves were significantly lower than those of E. japonica and Z. bungeanum.【Conclusion】 The photosynthetic physiological characteristics of E. japonica and Z. bungeanum show obvious response to light intensity. Z. bungeanum has the strongest photosynthetic capacity,while E. japonica has the best ecological adap-tability. In the future planting,it can be considered to increase the soil nutrients of E. japonica to improve its photosynthe-tic capacity,thereby increasing plant productivity. J. regia is prone to photoinhibition,and it is recommended to plant them in areas with lower maximum light intensity. In summary, Z. bungeanum and E. japonica are more suitable economic tree species for rockey desertification control in karst plateau valley area.

     

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