Department of Horticulture, Faculty of Agriculture, Yozgat Bozok University, Yozgat, Turkey.
Republic of Turkey Ministry of Agriculture and Forestry, Erzincan Horticultural Research Institute, Erzincan, Turkey.
Physiol Plant. 2024 Jul-Aug;176(4):e14437. doi: 10.1111/ppl.14437.
Drought represents the predominant and most critical abiotic stress challenge within the domain of viticulture, necessitating the identification and application of efficacious strategies to ameliorate its deleterious effects. In the contemporary realm of abiotic stress management, the deployment of α-lipoic acid (α-Lipo), known for its antioxidant capabilities, as an exogenous treatment has been investigated for mitigating various abiotic stresses in numerous plant species, yet a detailed exploration of its efficacy in alleviating drought stress in grapevines remains to be conclusively determined. This study aimed to elucidate the adaptive mechanisms against drought stress by examining the effects of different α-Lipo concentrations (0, 1, 25 and 50 μM) applied on the foliar under well-irrigated and drought conditions on American grapevine rootstocks '1103 P' (drought tolerant) and '3309 C' (drought sensitive). Our findings revealed that the efficacy of α-Lipo varied significantly depending on rootstock type and irrigation status. 1103 P rootstock treated with 1 μM α-Lipo under well-irrigated conditions showed greater positive effects on growth traits, photosynthetic and osmotic parameters. In contrast, in rootstock 3309 C under the same conditions, the highest effects were obtained at 25 and 50 μM α-Lipo concentrations. Under drought stress conditions, 50 μM α-Lipo treatment improved physiological parameters (chlorophyll content, proportional water coverage and stomatal conductance), proline content and antioxidant enzyme activities (SOD, CAT and APX), while reducing electrolyte leakage and MDA levels in both rootstocks, showing a strong potential to increase oxidative stress tolerance and sustain plant growth. Heatmap visualization analysis confirmed the data obtained from Principal Component Analysis (PCA) and revealed that 1103 P treated with 50 μM α-Lipo under drought stress conditions exhibited superior physiological performance compared to 3309 C under the same conditions. This indicates the importance of potential rootstock differences in stress adaptation or α-Lipo uptake efficiency. These findings suggest that α-Lipo holds promise as an eco-friendly, natural bio-stimulant for use in arid environments, contributing to the advancement of sustainable agricultural practices in the foreseeable future.
干旱是葡萄栽培领域中主要且极具挑战性的非生物胁迫因素，因此需要识别并应用有效的策略来减轻其有害影响。在当前的非生物胁迫管理领域中，已经研究了具有抗氧化能力的α-硫辛酸（α-Lipo）作为外源处理剂，以减轻许多植物物种的各种非生物胁迫，但α-Lipo 缓解葡萄干旱胁迫的功效仍需进一步确定。本研究旨在通过研究不同浓度的 α-Lipo（0、1、25 和 50 μM）在叶面喷施下对美国葡萄砧木‘1103 P’（耐旱）和‘3309 C’（耐旱）在充分灌溉和干旱条件下的影响，阐明其对干旱胁迫的适应机制。我们的研究结果表明，α-Lipo 的功效因砧木类型和灌溉状态而异。在充分灌溉条件下，1103 P 砧木用 1 μM α-Lipo 处理显示出对生长特性、光合作用和渗透参数的更大积极影响。相比之下，在相同条件下的 3309 C 砧木中，在 25 和 50 μM α-Lipo 浓度下获得了最高的效果。在干旱胁迫条件下，50 μM α-Lipo 处理可改善生理参数（叶绿素含量、比例水分覆盖和气孔导度）、脯氨酸含量和抗氧化酶活性（SOD、CAT 和 APX），同时降低两种砧木的电解质渗漏和 MDA 水平，表现出增强氧化应激耐受性和维持植物生长的强大潜力。热图可视化分析证实了主成分分析（PCA）获得的数据，并表明在干旱胁迫条件下，用 50 μM α-Lipo 处理的 1103 P 比在相同条件下的 3309 C 具有更好的生理表现。这表明潜在的砧木差异在适应胁迫或α-Lipo 吸收效率方面的重要性。这些发现表明，α-Lipo 有望成为干旱环境中使用的环保、天然生物刺激素，为可预见的未来可持续农业实践的发展做出贡献。
