Studies On Photosynthetic Characteristics Of Oil-tea Camellia Clones Under Different Yield Levels

In order to test the diurnal and seasonal variation of photosynthesis factors including Pn,Tr and other photosynthetic parameters which can be tested by Li-Cor6400 portable photosynthetic system,3 clones of oil-tea camellia under different yield level (high-yield, medium-yield and low-yield) were employed in this experiment.The work started from April of 2007 to March of 2008,which including 5 determination stages. The main factors which effect Pn,Tr,WUE were also analysised.The purpurse of this study is to lay a solid theoretical foundation for high photosynthetic efficiency breeding, to lay a theoretical basis for high quality and efficient cultivation, and to provide reference for improving photosynthetic capacity and yield.The results were as follows:1.Diurnal variations of Pn of oil-tea Camellia presented a single peak curve or a double-peak curve.When it presented a double-peak curve, midday depression of photosynthes may occurred to some extend.There are significant differences between high-yield clones and medium-yield clones,low-yield clones,Pn of high-yield clones is significantly higher than the other two clones. Diurnal variations of Tr,Cond and Ls present a single-peak curve while diurnal variations of Ci and WUE present a "U" curve.2.Seasonal variation of Pn present a transverse inverted "S" curve, the highest value presented in Octorber while the lowest presented in February,and change trend of the three varieties are the same.3.The leaf age has a great influence on Pn, Pn of one-year-old leaves is higher than that of 2-year-old leaves;the leaf position has little inflence on Pn, there was little difference in Pn between upper leaves and lower leaves.4.Annual varition of chlorophyll content of leaves of oil-tea Camellia is complicated, but change trend of the three clones are the same. There are highly significantly positive correlation between Pn and chlorophyll a,chlorophyll b and total chlorophyll,and the pearson correlation coefficient are 0.950,0.888,0.963 respectively. 5.The main physio-ecological factors which affect Pn most are Cond,Ci and PAR, which affect Tr most are Cond and PAR, and Tair and Ci are the main physio-ecological factors which affect WUE most.