Effects of Drought on Nutrient Uptake and Assimilation in Vegetable CropsPlant Responses to Drought Stress

Scarcity of water is a severe environmental limit to plant productivity. Drought-induced loss in crop yield probably exceeds losses from all other causes, since both the severity and duration of the stress are critical. Nutritional imbalance under drought conditions depresses plant growth and therefore productivity by affecting nutrient uptake, transport, and distribution. Despite contradictory reports on the effects of nutrient supply on plant growth under drought conditions, it is generally accepted that an increased nutrient supply will not improve plant growth when the nutrient is already present in sufficient amounts in the soil and the drought is severe. A better understanding of the role of mineral nutrients in plant resistance to drought will contribute to improve fertilizer management in arid and semiarid areas and in regions suffering from temporary drought. Considering that vegetables are concentrated in semiarid zones where water stress is frequent, it is important to ascertain how this type of stress affects the nutrient uptake and assimilation of these crops. This chapter starts with an overview of the recent literature on plant nutrition of vegetables under drought conditions, stressing mainly the effects of drought on nutrient availability, uptake, transport, and accumulation in plants, and also the interactions between nutrient supply and drought response; it then proceeds to identify the means to increase nutrient availability under drought conditions through breeding, grafting, and fertilization.