Physiological studies on the leaves of Populus deltoides in relation to nitrate assimilation

Maximum number of Populus deltoides leaves per plant were observed in the month of April and minimum in July, whereat maximum number of leaves were shed in the month of November. When the observations of 10 to 145 days old leaves were pooled, fresh wt. dry wt. and leaf area showed significant positive correlation with the leaf age and negative with moisture contents. Nitrate reductase activity on fresh and dry wt. basis showed second and third degree polynomial regression with leaf age.