Effects of Low Temperature on Photosynthetic and Chlorophyll Fluores-cence Parameters of Coffea arabica
To investigate the mechanism of cold-resistance in Coffea arabica,one-year-old Coffea arabica plants were treated by four different low temperatures of 8 ℃,4 ℃,0 ℃,-2 ℃ were used to study the effects of photo-synthetic parameters and chlorophyll fluorescence parameters in leaves.The results showed that the degree of chilling injury of Coffea arabica plants is increasing with the decrease of temperature and the extension of treat-ment time,chlorophyll(Chl)content,net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),water use efficiency(WUE),stomatal limit value(Ls)of photosynthetic parameters,and actual photochemical quantum yield(ΦPSⅡ),photochemical quenching coefficient(qP)and quantum transfer rate(ETR)of chlorophyll fluorescence parameters as a whole were declined after rising.The intercellular CO2 concentration(Ci)and initial fluorescence(Fo)are increasing,while the maximal photochemical yield(Fv/Fm)decreases gradually.Correlation analysis showed that Chl,Pn,WUE,Ls,ETR,qP and qN of coffea was positive correlated with cold resistance,but the negative correlation between the Ci,Tr and the others.The chlorophyll fluorescence characteristics of sorghum seedlings were weakened by low-temperature stress treatment.The results would provide reference for the screen-ing excellent cold resistant germplasm and resistance molecular mechanism research of coffee.
Coffea arabicaLow temperature stressPhotosynthesisChlorophyll fluorescence
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