Phosphorus nutrition and water stress tolerance in wheat plants

Abstract

The effect of phosphorus (P) nutrition and soil water availability (W) on the growth of wheat (Triticum aestivum L.) plants was studied in two pot experiments. Several levels of P supply were applied once before sowing. Before seedling establishment, the pots were kept near 100% of field capacity (FC). Afterwards, half of the pots were maintained between 60-70% FC. Control pots were kept at 85-95% FC by weighing and watering every two to three days. Several harvest of shoots were done before anthesis. At each harvest, dry matter and total P accumulation were measured in shoots. The main differences between both experiments were the way the drought stress was imposed, the levels of P supply, and the developmental stage of the plants at each harvest. In Experiment 1, no additional P resulted in a reduction of the shoot dry matter of 24 and 48% for well watered and drought-stressed plants, respectively. In Experiment 2, these reductions were of 33 and 65% for well-watered and drought-stressed plants, respectively. In both experiments, the effect of the drought-stress treatment was different at different levels of P supply. Interactions between P and W treatments were attributed to both, a less intense drought stress in P0 plants, and to the enhancement of drought-stress tolerance in P100 plants (Experiment 1), and P60 plants (Experiment 2). 30 RODRIGUEZ ET AL. INTRODUCTIONThe amount of plant material at the end of a growing season is the result of a large number of interacting processes in the soil-crop system. Particularly in rainfed agriculture, not one but many factors may limit this interaction. Water stress has often been directly or indirectly related to plant mineral nutrition. When little water is available, ions become less mobile in the soil, making the pathway from the soil to the root surface less direct (1). Because the rate of ion diffusion to the root surface is usually the rate-limiting step in nutrient uptake, reductions in water availability could affect plant growth not only directly but also through a lower availability of nutrients. Day (2) found that tissue concentrations of growth-limiting nutrients often decline during water stress, whereas one would expect them to increase if water directly restricted growth more strongly than nutrient uptake (3). This would suggest that the effects of low soil water content on nutrient availability may be nearly as important as the direct effects of water stress on plant growth. It has also been argued that a moderate nutrient stress would reduce the susceptibility of plants to other stresses. Chapin (4) mentioned that plants that are growing rapidly because of high nutrient availability are generally more susceptible to frost and water stress. However, Saneoka (5) found that despite that the stomatal resistance increasing with decreasing leaf water potential, at both high and low levels of P addition, the increase was higher at lower than at higher levels of P nutrition. For intermittent drought stress, a higher stomatal sensitivity under P stress conditio...

Application of silicon enhanced drought tolerance in Sorghum bicolor

“…All of these elements improved dry matter production in both wet and dry conditions (e.g. Rodriguez et al 1996). Silicon is distinct from these elements, as silicon‐induced acceleration of dry matter production in sorghum is observed only when the plants are subjected to drought (Tables 1 and 2).…”

Effects of phosphorus and drought stresses on dry matter and phosphorus allocation in wheat

“…The interactions observed in this study were thoroughly studied in a previous paper (16). Generaly, the final shoot dry weight and P uptake increased with the level of P supply.…”

Phosphorus Supply Increases Internode Length and Leaf Characteristics, and Increases Dry Matter Accumulation and Seed Yield in Soybean under Water Deficit

“…Previous studies showed that P supply can ameliorate the adverse effects of drought on yield performance in many crops such as wheat [14], barley [15], soybean [5,7,16,17] and cowpea [18]. In these crops, the improvement in seed yield with P supply under different water deficits was associated with an increase in dry matter accumulation [5,7,16], but there is little information about how the increased P supply affects specific shoot traits when subjected to a water deficit.…”