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

Dhananjay K. Singh (Lead / Corresponding author), Peter W.G. Sale, Charles K. Pallaghy, Blair M. McKenzie

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

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 <0.001). 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.

Original languageEnglish
Pages (from-to)249-259
Number of pages11
JournalNew Phytologist
Volume146
Issue number2
DOIs
Publication statusPublished - 7 Jul 2008

Keywords

  • Abscisic acid (ABA)
  • Dry soil
  • Phosphorus
  • Transpiration rate
  • Water use efficiency (WUE)
  • White clover (Trifolium repens)

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