Physiological and ecological characteristics of Coffea arabica under different light environments

Objective Physiological and ecological adaptation mechanism of Coffea arabica to different light environments was studied to provide reference for high yield and standardized cultivation of it.Method Maximum net photosynthetic rate(Pmax),fluorescence parameters,nitrogen content of unit dry weight(N),construction cost(CC),chlorophyll of unit weight (Chl),carotenoid content and anatomical structure characteristics of C.arabica leaf under 100%,36% and 4% light environment were compared,and adaptability of C.arabica to different light environments was analyzed.Result As light intensity enhanced,Pmax and non photochemical quenching coefficient (NPQ) increased,photochemical efficiency at midday(Fv/Fm) significantly decreased(P<0.05).The results showed,N and CC input were high in C.arabica leaf under 100% light environment,Pmax,photosynthetic nitrogen use efficiency (PNUE) and photosynthetic energy use efficiency (PEUE) was high.As light intensity increased,chlorophyll/carotenoid (Chl/Car),leaf thickness (LT),mesophyll structure tense ratio (MTR),stomatal pore area index (SPI) and vein density (VD) were on the rise,but specific leaf area (SLA) and mesophyll structure loosened ratio (MLR) decreased.Conclusion As a cash crop which requires shading cultivation,C.arabica is sensitive to strong light.It can adapt to the change of light environment by adjusting physiological and ecological characteristics to reduce the damage to its photosynthetic organs.