Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris L. under different soil moisture levels near Nairobi, Kenya.

Abstract

Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris cv. GLP-2 were investigated under two soil moisture levels in two contrasting seasons near Nairobi, Kenya. The experiment confirms that dry weights and yields of Phaseolus vulgaris are limited by a drought induced decrease in leaf area, leading to less radiation interception as a source for assimilation. However, photosynthetic efficiency in Phaseolus vulgaris decreased and contributed to these effects. Decreases of economic efficiency as obtained in the second season, where stress lasted much later into the season, showed that a drought limits the partitioning and translocation of assimilates to the seeds of Phaseolus vulgaris.