Abstract:

Rapid and precise methods were used to establish liner and exponent function regression equations between leaf area and leaf length, leaf width, or product of leaf length and leaf width for four clones of Populus tomentosa. The results showed that：1) Leaf indexes of different clones of Populus tomentosa have significant differences and regression equation in different clones are not the same，leaf area should be calculated according to clones; 2) Leaf area at different growth stages is different in regression equation and the regression equation at different growth stages should be determined. 3) the correlationship of leaf area and product of leaf length and leaf width is the most significant among one-factor linear regression equations, which is only suitable for the measurement of functional leaves; and in the power function regression equations,the correlationship of leaf area and leaf width is significant and there are no restrictions on leaf size.Power function regression equation of clone-50 of Populus tomentosa is LA=1.0014×W1.8295，power function regression equation of clone-83 of Populus tomentosa is LA=0.863×W1.832，power function regression equation of clone-30 of Populus tomentosa is LA=0.554×W2.051，power function regression equation of clone-B331 of Populus tomentosa is LA=1.639×W1.600.Therefore,leaf area can be estimated by measuring leaf width of four clones of Populus tomentosa,using their power function regression equations.