5−Aminolevulinic Acid Induces Regulation in Growth, Yield and Physio-Biochemical Characteristics of Wheat under Water Stress

Abstract

The production of wheat crop is below average in many regions of the world which is ascribed to adverse environmental conditions including drought stress. The present study was conducted to appraise the beneficial role of exogenouslyapplied 5-aminolevulinic acid (ALA) on growth, yield and some key physio-biochemical characteristics of two commercially important wheat cultivars (Shafaq-06 and Uqab-2000) under well watered [100% field capacity (FC)] and water-deficit (60 and 80% FC) conditions. Imposition of varying water regimes significantly decreased fresh and dry weights of shoots, photosynthetic pigments (a and b), non-photochemical quenching of chlorophyll fluorescence (NPQ), quenching coefficient for non-photochemical (N) of chlorophyll fluorescence (qN), K + (potassium ion), Ca 2+ (calcium ion) and P (phosphorus) accumulation in shoot and root and yield-related attributes. In contrast, water deficit regimes caused improvement in F v /F m (chlorophyll fluorescence measurement), coefficient of photochemical quenching (qP), proline, glycinebetaine (GB) and hydrogen peroxide (H 2 O 2) contents. Foliar spray of ALA at the rate of 50, 100 and 150 mg/L along with control (no spray (NS) and/or water spray (WS)) significantly enhanced chlorophyll a and b pigments, qN, NPQ, qP, K + , Ca 2+ and P accumulation in both roots and shoots, proline, GB, total phenolics and malondialdehyde (MDA) contents and yield. The wheat Shafaq-06 was better in shoot dry weight, qN, NPQ and F v /F m , shoot and root K + , root Ca 2+ , proline, GB accumulation and yield attributes, while Uqab-2000 was better in chlorophyll a contents, root P and MDA contents. Overall, better growth and yield of Shafaq-06 than Uqab-2000 under water deficit regimes was found to be associated with ALA improved leaf fluorescence (qN, NPQ and F v /F m), shoot and root K + , root Ca 2+ , proline and GB accumulation.

Exogenous 5-Aminolevulinic Acid Promotes Osmotic Stress Tolerance of Walnuts by Modulating Photosynthesis, Osmotic Adjustment and Antioxidant Systems

“…The osmotic stress leads to the accumulation of osmotically active solutes, soluble sugars, soluble proteins, and free proline, and, interestingly enough, the exogenous ALA application further assisted in facilitating accumulation of these solutes to heighten the OA in walnut leaves and roots (Figure 5). Especially, the further accumulation of free proline in walnut leaves and roots was consistent with the phenomena reported in wheat [21], Chinese rye grass [22] and strawberry [23] under drought stress. These demonstrate that ALA stimulates the osmotic solute production, which can attract the accumulation of compatible solutes to reinforce hydration and maintain turgor in cells [9,47].…”

“…As a potential growth regulator, ALA can promote plant growth and strengthen plant tolerance to various environmental stresses, including abiotic stresses (such as drought [20,23], salinity [39] and extreme temperatures [40,41]) and biotic stresses (such as pathogen infection [42]). With regard to various crops which suffered from drought stress, their drought tolerance was all improved by applying exogenous ALA on wheat [21,43], Kentucky bluegrass [20], sunflower [25], rapeseed [44] and cucumber [17]. Although the effect of exogenous ALA has been gradually clarified over the years, the mechanism of ALA-mediated drought resistance has not been thoroughly revealed.…”

“…Until now, ALA can enhance the drought tolerance in diverse plants, such as poplar [16], cucumber [17], banana [18] and so on. Priming with ALA raises the leaf relative water content (RWC) in oilseed rape [19] and Kentucky bluegrass [20], and enhances the content of soluble sugars, proline and other osmolytes in wheat (Triticum aestivum) [21] and Chinese rye grass (Leymus chinensis) [22], as well as the promotion of chlorophyll content and photosynthetic efficiency to preserve photosynthetic capacity in rapeseed and wheat under drought stress [19][20][21][22]. The previous study of ALA improving the strawberry drought tolerance may reveal the mechanism of action [23].…”

Methionine-induced regulation of growth, secondary metabolites and oxidative defense system in sunflower (Helianthus annuus L.) plants subjected to water deficit stress

“…Under water deficit conditions, plants develop mechanisms that could help the plants in survival and improved rate of production [ 7 , 8 ]. Under deficiency of water, plants upregulate defense mechanism for their survival and get control of increased accumulation of ROS (reactive oxygen species) [ 8 – 11 ].…”

Seeds primed with 5-aminolevulinic acid mitigated temperature and drought stresses of wheat at germination and early seedling growth

“…In this regard, 5-ALA and citric acid can effectively mitigate chromium stress on sunflower (Farid et al, 2020). It is reported that 5-ALA successfully mitigated the adverse effects of environmental stresses of different plants species including, chilling stress in rice (Sheteiwy et al, 2017), water stress in wheat (Akram et al, 2018), and low temperature and weak light in cucumber seedling (Anwar et al, 2020).…”