Water Relations, Abscisic Acid and Yield of Wheat Plants in Relation to the Interactive Effect of Seawater and Growth Bioregulators

Abstract

Irrigation of wheat plants with seawater (10 and 25 %) led to significant increases in free and bound abscisic acid (ABA) in leaves, especially at 25 %. The relative water content (RWC) and water use efficiency (calculated from grain yield, WUEG, or from biomass yield, WUEB) of the seawater‐irrigated plants were lower than those of the control. Grain pre‐soaking in gibberellic acid (GA3), indole‐3‐acetic acid (IAA) or ABA reduced the levels of accumulated ABA (free and bound) produced by seawater irrigation. The stress imposed by seawater generally reduced yield and yield components of wheat plants and the effect was more pronounced at the higher level of seawater irrigation (25 %). Furthermore, seawater treatments decreased the carbohydrate content and increased the protein content of the developing grains. The effect of seawater treatments on ion concentrations in the developing grains was not consistent. The application of growth bioregulators appeared to mitigate the effect of seawater salinity stress on wheat productivity. GA3 was the most effective hormone in this regard. The economic yield (grain yield) had a strong positive correlation with RWC, WUEG, WUEB, plant height, shoot fresh and dry weight, grain number/main spike, kernel weight and harvest index.

Effects of varied water regimes on root length, dry matter partitioning and endogenous plant growth regulators in sunflower (Helianthus annuusL.)

“…However root/shoot, reproductive/vegetative ratios and ABA concentration were found higher under drought stress. Increase in ABA concentration in response to different type of stresses has been previously documented (Aldesuquy & Ibrahim 2001, Gniazdowska et al 2007) while increased ratios under drought stress may be due to enhanced mobilization of assimilates to the roots or reproductive parts. All genotypes showed very strong relationship of ABA with root/shoot (R 00.75; p 50.001) and reproductive/vegetative ratios (R 0 0.85, p 50.001) at each development phase under drought regime.…”

Effects of Salinity on Vegetable Growth and Nutrients Uptake

“…However ABA is only one component of composite hormonal control (Ross & O'Neill, 2001;Nemhauser et al, 2006). It was found that the concentration of ABA and cytokinins increase with increasing in salt concentration (Aldeuquy & Ibrahim, 2001, Vaidyanathan et al, 1999. Abscisic acid may modify the expression of genes affected by salts, and these genes likely play a significant role in the mechanisms of tobacco tolerance to excess salts (Boussiba & Richmond, 1976).…”

An advantageous level of irrigation water salinity for wheat cultivation

“…Salinity exerts negative influences on wheat with an ultimate reduction in yield (Aldesuquy and Ibrahim, 2002;Ghane et al, 2011). In addition to yield reduction, Zaire and Khuble (1990) reported significant interactions between salinity and wheat cultivars.…”