Exogenous abscisic acid reduces water loss and improves antioxidant defence, desiccation tolerance and transpiration efficiency in two spring wheat cultivars subjected to a soil water deficit

Abstract

The effect of soil drenching with 10 µM abscisic acid (ABA) on the physiological responses of two spring wheat (Triticum aestivum L.) cultivars released in different decades was evaluated when subjected to a water deficit at jointing or at booting. Exogenous ABA application increased the ABA concentration in the leaves, reduced the stomatal conductance (gs), slowed the rate of water use, decreased the lethal leaf water potential (ψ) used to measure desiccation tolerance and lowered the soil water content (SWC) at which leaf relative water content (RWC) began to decrease and wilting was observed. Exogenous ABA application also reduced reactive oxygen species (ROS) formation and increased antioxidant enzyme activity, leading to a reduction in the oxidative damage to lipid membranes in both cultivars exposed to water stress at jointing and booting. The decrease in leaf RWC and wilting occurred at lower values of SWC in the recently-released cultivar than in the earlier-released cultivar. The recently-released cultivar also had higher grain yield than the earlier-released cultivar at moderate water stress, but the grain yield in both cultivars was reduced by water stress and by the exogenous ABA treatment. However, exogenous ABA treatment increased transpiration efficiency for grain (TEG) of both cultivars under moderate water stress. These results indicate that ABA played an important role in slowing water use and enhancing the antioxidant defence during soil drying, but this did not result in increased yields under drought stress.

Photosynthesis is Reduced, and Seeds Fail to Set and Fill at Similar Soil Water Contents in Grass Pea (Lathyrus sativus L.) Subjected to Terminal Drought

“…, Du et al. ). However, flower production and initial pod development continued until the PAWC was below 40 %, that is below the PAWC at which the Ψ leaf began to decrease.…”

Old and New Cultivars of Soya Bean (Glycine max L.) Subjected to Soil Drying Differ in Abscisic Acid Accumulation, Water Relations Characteristics and Yield

“…Du et al. (, ) found that exogenous BABA or ABA could induce ABA accumulation in the leaves and stomatal closure earlier and enhance leaf desiccation tolerance in wheat under drought. In our study, the new soya bean cultivars JD and ZH had a higher concentration of ABA in the leaf for the first 10 days after withholding water (Fig.…”

24-epibrassinolide increases growth, grain yield and β-ODAP production in seeds of well-watered and moderately water-stressed grass pea

“…Exogenous application of ABA to the leaves of wheat improved grain yields in the field (Travaglia et al 2010) and increased the WUE of tree seedlings under moderate stress in the field (Duan et al 2007). In contrast, exogenous ABA applied to soil was shown to enhance endogenous ABA accumulation, decrease the grain yield, but increase the transpiration efficiency for grain in wheat (Du et al 2013). Jager et al (2008) found, however, no significant differences in endogenous ABA concentration among wild-type plants, a brassinosteroid-deficient mutant (Ikb) and a brassinosteroid-perceptive mutant (Ika) of pea (Pisum sativum L.) subjected to water stress, suggesting that EBL and ABA may function along two different pathways in plants.…”

“…The leaf ABA concentration was determined following the method of Du et al (2013). Shredded fresh leaves (0.5 g) were added to 4 mL of 80 % methanol solution containing 1 mM butylated hydroxytoluene (BHT) in an ice bath and homogenized before being incubated at 4°C for 4 h and centrifuged at 10,000g for 0.25 h at 4°C.…”