A Comparative Study on the Photosynthetic Characteristics of Eureka Iemon in Different Elevation Regions

Purpose The objective of this study is to provide optimal basis for culturing Eureka lemon at different elevations by comparing its photosynthetic characteristics at 300, 420, 800, and 1 110 m elevations.

Method Study field is Honghe River Basin, and study targets such as photosynthetic parameters net photosynthetic rate (G_s), intercellular CO₂ concentration (C_i), stomatal conductance (G_s), transpiration rate (T_r) were studied to further discuss relevant environmental factors changes, and the light response curve was measured as well.

Result (1) The photosynthetically active radiation and atmospheric temperature of Eureka lemon planting in the four areas at different elevations were single peak type curves, and the relative humidity of the leaf surface depicted a trough-type curve. The highest and lowest points were observed at 12:00 in the noon. (2) The P_n of lemons at four elevations were single peak type curves, which kept ascent when elevations rise to 1 110 m, then curves went down. By comparison, the P_n at 800 m and 1 100 were obviously higher than that at 420 m and 300 m. (3) The fitting results of the light response curve showed that the P_nmax and apparent quantum efficiency (AQE) were as followings: 800 m>1 110 m>420 m>300 m.

Conclusion The characteristics of photosynthesis of Eureka lemon in four elevations were: 800 m>1 110 m>420 m>300 m. That is, the suitable elevation for cultivation is between 800-1 110 m.