Phosphorus concentrations in the leaves of defoliated white clover affect abscisic acid formation and transpiration in drying soil

Abstract

Increased leaf phosphorus (P) concentration improved the water-use efficiency (WUE) and drought tolerance of regularly defoliated white clover plants by decreasing the rate of daily transpiration per unit leaf area in dry soil. Night transpiration was around 17% of the total daily transpiration. The improved control of transpiration in the high-P plants was associated with an increased individual leaf area and WUE that apparently resulted from net photosynthetic assimilation rate being reduced less than the reductions in the transpiration (27% vs 58%). On the other hand, greater transpiration from low-P plants was associated with poor stomatal control of transpirational loss of water, less ABA in the leaves when exposed to dry soil, and thicker and smaller leaf size compared with high-P leaves. The leaf P concentration was positively related with leaf ABA, and negatively with transpiration rates, under dry conditions (P 0n001). However, leaf ABA was not closely related to the transpiration rate, suggesting that leaf P concentration has a greater influence than ABA on the transpiration rates.

The Role of Plants in the Effects of Global Change on Nutrient Availability and Stoichiometry in the Plant-Soil System

“…Higher concentrations of P in plants improve WUE because they allow a minor suppression of photosynthesis per unit of water transpired (Singh et al, 2000;Jones et al, 2005) and improve the capacity of stomatal control (Waraich et al, 2011). Enzymes of N metabolism play an important role in the acclimation to drought (Xu and Zhou, 2006).…”

Soil Enzyme Activity in a Mediterranean Forest after Six Years of Drought

“…Th is has a direct eff ect on the photosynthetic capacity and an indirect eff ect on water use effi ciency (WUE). In fact, several experiments have observed that low nutrient availability can diminish WUE (Sing et al, 2000;Ruiz-Lozano et al, 2001). If drought changes the N availability in soil, it will also aff ect the capacity of plants to capture N, thus aff ecting WUE, since WUE is positively correlated with leaf N concentration (Sing et al, 2000;Ruiz-Lozano et al, 2001;Fernández et al, 2006).…”

Interactive effects of water, nitrogen and phosphorus on the growth, biomass partitioning and water-use efficiency of Bauhinia faberi seedlings

“…Partitioning more biomass to roots and maintaining higher root shoot ratio are advantageous to drought-adapted plants as drought and nutrient stress occur, because greater water absorptive component (fine root) can sustain more water and nutrient uptake for transpiration and respiratorion (Singh et al, 2000;Gleeson and Good, 2003;Qu et al, 2003).…”