Abstract
The photosynthetic rate per unit leaf area (PA) was positively and curvilinearly related to leaf areal nitrogen content. A quadratic estimation for PA in content was proposed for cultivated varieties of sativa. A further increase in leaf areal nitrogen content may produce a higher PA. The photosynthetic rate per unit leaf nitrogen was negatively related to leaf areal nitrogen content. Further, differences in PA between leaves with different nitrogen contents were not marked under low light intensities. High leaf areal nitrogen content may not necessarily be favorable when the plants are grown under lower nitrogen supply and/or light intensity levels.
