Growth and Physiological Response of Seedlings of Populus deltoides Clones to Different Photoperiods

【Objective】This study aims to investigate the performance of plant growth traits of Populus deltoides clones under different photoperiod treatments, and screen the traits that can effectively evaluate photoperiod sensitivity of P. deltoides, so as to clarify the effect of photoperiods on physiological status of P. deltoides clones with different sensitivity. 【Method】 In this study,26 clones of P. deltoides were used as the research materials, and subjected to two photoperiod treatments（light 16 h/dark period 8 h, light 8 h/dark period 16 h） in artificial climate chambers. A total of 12 growth traits of P. deltoides were continuously observed at multiple time points under different photoperiod treatments, and the subordinate function method and principal component analysis were used to obtain the comprehensive evaluation index D value of photoperiod sensitivity of growth traits of P. deltoides.Regression analysis and path analysis were used to screen the direct effect indexes suitable for the evaluation of pho