Correlation Analysis on Net Photosynthetic Rate and Impact Factors of Grafted Cucumber

The correlation between the diurnal change of net photosynthetic rate and impact factors of the grafted cucumber(Cucumis sativus L.)in fruiting stage was analyzed by LI-6400 photosynthesis measure system.The results indicated: Net photosynthetic rate,photosynthesis effective radiation,stomatal conductance and transpiration rate of grafted cucumber were all single-peak curve whenever in sunny day or cloudy day.The concentration of CO2 in intercellular space changed as "U" and the leaf temperature changed as inverted "U".The optimization equation of Pn in sunny day attained by the method of stepwise multi-regression was y=26.077 5+0.000 6x1+15.809 0x3-0.080 4x4,in cloudy day was y=72.594 6+0.043 6x1+2.812 9x3+ 0.187 6x4.The analysis of partial correlation and path showed that the diurnal variation of Pn had significant correlation with PAR and Cond,the order of effecting ability was Cond PAR Tr Ci in sunny day and PAR Ci Tl in cloudy day.