Role of gibberellins, neem leaf extract, and serine in improving wheat growth and grain yield under drought-triggered oxidative stress

Abstract

The foliar application of gibberellins (GA₃), neem leaf extract (NLE) and serine can be proven as effective growth regulating agents to counter drought stress-related deleterious effects. The literature about the collaborative role of these substances in foliar spray application under drought stress is not available to this date. No single report is available in literature on combine foliar application of GA₃, NLE, and serine in improving wheat growth and yield under drought-triggered oxidative stress. The objective of this study was to induct tolerance against drought stress in order to sustain maximum growth and yield of wheat varieties (Anaj-2017 and Galaxy-2013) with foliar applications of GA₃, NLE, and serine. The current field trial was designed to disclose the protective role of these substances in wheat varieties (Anaj-2017 and Galaxy-2013) under water-deficit stress. Two irrigation levels, i.e., control (normal irrigation) and water stress (water deficit irrigation), and 5 levels of GA₃, NLE and serine i.e., control (water spray), GA₃ (10.0 ppm), NLE (10.0%), serine (9.5 mM), and mixture (GA₃ + NLE + serine) in a 1:1:1 ratio was applied. Application of these substances improved the pigments (Chlorophyll a, b), carotenoids, growth, biomass, and grain yield traits of both wheat varieties under water-deficit stress. Activities of antioxidant enzymes (POD, CAT and SOD), and non-enzymatic antioxidants (proline, total phenolic contents, anthocyanin and free amino acids) were up-regulated under drought stress and with foliar spray treatments. The foliar applications of these substances reduced the drought triggered overproduction of lipid peroxidation (MDA) and H₂O₂. The study found that Galaxy-2013 variety is more tolerant to drought stress than Anaj-2017, while co-applied treatments (GA₃ + NLE + serine) were shown to be the most effective among all applications.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-023-01402-9.

Keywords: Antioxidant defense; Growth promotors; Osmolytes; Reactive oxygen species.

Fig. 1

Exogenous application of GA₃, NLE and serine on A shoot fresh weight (SFW), B shoot dry weight (SDW), C root fresh weight (RFW), D root dry weight (RDW), E shoot length (SL), F root length (RL), G grain yield/plant and (H) 100-grain weight of wheat under normal and water-deficit irrigation The letters on bars are significantly different at 95% confidence level (n = 3).

Fig. 2

Exogenous application of GA₃, NLE and serine on A spikes (plant⁻¹), B kernel (spike⁻¹), C chlorophyll a, D chlorophyll b, E carotenoids, F malondialdehyde (MDA), G hydrogen peroxide (H₂O₂), and H membrane permeability (MP) of wheat under normal and water deficit irrigation. The letters on bars are significantly different at 95% confidence level (n = 3)

Fig. 3

Exogenous application of GA₃, NLE and serine on A total anthocyanin contents (TAC) B total free amino acids (TFAA), C superoxide dismutase (SOD), D peroxidase (POD), E catalase (CAT), F total soluble protein (TSP), G total phenolic contents (TPC), and H proline of wheat under normal and water-deficit irrigation. The letters on bars are significantly different at 95% confidence level (n = 3)

Fig. 4

Heatmap histogram correlation between different studied attributes of wheat plants under normal [Anaj-17 Control (1), GA₃ 0.001% (2), serine 0.1% (3), NLE 10% (4), mixture (5)] Galaxy-2013 Control (6), GA₃ 0.001% (7), serine 0.1% (8), NLE 10% (9), mixture (10)] and water deficit irrigation [Anaj-17 Control (11), GA3 0.001% (12), serine 0.1% (13), NLE 10% (14), mixture (15)] Galaxy-2018 Control (16), GA₃ 0.001% (17), serine 0.1% (18), NLE 10% (19), mixture (20)]

Fig. 5

Principal Component Analysis showing association among growth, photosynthetic, yield and antioxidant attributes of wheat plants under normal and water deficit irrigation

Fig. 6

Mechanistic overlook of GA₃, NLE and serine mediated wheat growth and grain yield under water deficit stress