Effects of Drought Stress on Growth and Nitrogen Assimilation by Common Beans

Abstract

Drought stress is one of the most important limitations for common bean (Phaseolus vulgaris) crops in the Argentinean North West. Frequently, the combined effects of high temperature and rainfall scarcity cause rapid increments in atmospheric water demand that lead to sudden, severe drought stress situations during the crop season. Approaches to prevent crop damages will derive from optimization of both genetic resources and crop management options. To succeed, these approaches must take into account the physiological plant strategies to face with the stress situation. Nitrogen nutrition in common bean is dual: atmospheric nitrogen may be fixed by the root nodules and/or inorganic nitrogen may be assimilated from soil solution. Therefore, common beans might have developed different strategies according with each N-nutrition way, and in particular, different levels of tolerance might be reached. In a first attempt to identify the best strategy of plants to hold a severe drought stress, we compared the plant tolerance to drought in relation with its growth, as conditioned by each N-nutrition way.