LONGEVITY AND PRODUCTIVITY OF LEAVES OF A CULTIVATED ANNUAL, GLYCINE MAX MERRILL. I. LONGEVITY OF LEAVES IN RELATION TO DENSITY AND SOWING TIME

Abstract

A life‐table approach has been applied to the leaf population of the soybean plant (Glycine max Merrill) in order to determine leaf longevity, a basic factor in production of dry matter. Longevity of leaves was determined at various heights on the stems of plants grown at three densities at three different sowing times. In general, longevity increases with the height of the leaf on the stem, but the uppermost leaves have short lives due to frost‐damage. In the plants sown earlier than the standard sowing time the lowest leaves fell very rapidly as a result of physiological ageing. It was concluded that, at the densities examined, density does not show a generalized relationship with leaf longevity. At the lower nodes, most leaves fell due to physiological ageing, but those at the higher nodes suffered from noxious insects. Two typhoons had little influence on leaf longevity. Copyright © 1979, Wiley Blackwell. All rights reserved