School of Engineering, Anhui Agricultural University, Hefei, 230036, China.
Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, 712100, China.
Plant Physiol Biochem. 2024 Sep;214:108906. doi: 10.1016/j.plaphy.2024.108906. Epub 2024 Jul 4.
The impact of drought events on the growth and yield of wheat plants has been extensively reported; however, limited information is available on the changes in physiological characteristics and their effects on the growth and water productivity of wheat after repeated drought stimuli. Moreover, whether appropriate drought stimulus can improve stress resistance in plants by improving physiological traits remains to be explored. Thus, in this study, a pot experiment was conducted to investigate the effects of intermittent and persistent mild [65%-75% soil water-holding capacity (SWHC)], moderate (55%-65% SWHC), and severe drought (45%-55% SWHC) stress on the growth, physiological characteristics, yield, and water-use efficiency (WUE) of winter wheat. After the second stress stimulus, persistent severe drought stress resulted in 30.98%, 234.62%, 53.80%, and 31.00% reduction in leaf relative water content, leaf water potential, photosynthetic rate (P), and indole-3-acetic acid content (IAA), respectively, compared to the control plants. However, abscisic acid content, antioxidant enzyme activities, and osmoregulatory substance contents increased significantly under drought stress, especially under persistent drought stress. After the second rehydration stimulus (ASRR), the actual and maximum efficiency of PSII and leaf water status in the plants exposed to intermittent moderate drought (IS2) stress were restored to the control levels, resulting in P being 102.56% of the control values; instantaneous WUE of the plants exposed to persistent severe drought stress was 1.79 times that of the control plants. In addition, the activities of superoxide dismutase, peroxidase, catalase, and glutathione reductase, as well as the content of proline, under persistent mild drought stress increased by 52.98%, 33.47%, 51.95%, 52.35%, and 17.07% at ASRR, respectively, compared to the control plants, which provided continuous antioxidant protection to wheat plants. This was also demonstrated by the lower HO and MDA contents after rehydration. At ASRR, the IAA content in the IS2 and persistent moderate drought treatments increased by 36.23% and 19.61%, respectively, compared to the control plants, which favored increased aboveground dry mass and plant height. Compared to the control plants, IS2 significantly increased wheat yield, WUE for grain yield, and WUE for biomass, by 10.15%, 32.94%, and 33.16%, respectively. Collectively, IS2 increased grain growth, yield, and WUE, which could be mainly attributed to improved physiological characteristics after drought-stimulated rehydration.
干旱事件对小麦生长和产量的影响已被广泛报道;然而,关于在重复干旱刺激后,生理特征的变化及其对小麦生长和水分生产力的影响,信息有限。此外,适当的干旱刺激是否可以通过改善生理特性来提高植物的抗逆性,仍有待探索。因此,本研究采用盆栽试验,研究间歇性和持续性轻度[65%-75%土壤持水量(SWHC)]、中度(55%-65% SWHC)和重度干旱(45%-55% SWHC)胁迫对冬小麦生长、生理特性、产量和水分利用效率(WUE)的影响。第二次胁迫刺激后,与对照植株相比,持续性重度干旱胁迫分别导致叶片相对含水量、叶片水势、光合速率(P)和吲哚-3-乙酸含量(IAA)降低 30.98%、234.62%、53.80%和 31.00%。然而,干旱胁迫下,脱落酸含量、抗氧化酶活性和渗透调节物质含量显著增加,尤其是持续性干旱胁迫下。第二次再水合刺激(ASRR)后,间歇性中度干旱(IS2)胁迫下的叶片 PSII 实际和最大效率以及叶片水分状况恢复到对照水平,导致 P 为对照值的 102.56%;持续性重度干旱胁迫下的瞬时水分利用效率是对照植株的 1.79 倍。此外,持续性轻度干旱胁迫下的超氧化物歧化酶、过氧化物酶、过氧化氢酶和谷胱甘肽还原酶的活性以及脯氨酸的含量在 ASRR 时分别比对照增加了 52.98%、33.47%、51.95%、52.35%和 17.07%,为小麦植株提供了持续的抗氧化保护。再水合后 HO 和 MDA 含量较低也证明了这一点。ASRR 时,IS2 和持续性中度干旱处理的 IAA 含量分别比对照增加了 36.23%和 19.61%,有利于地上干重和株高的增加。与对照植株相比,IS2 显著提高了小麦产量、籽粒产量水分利用效率和生物量水分利用效率,分别提高了 10.15%、32.94%和 33.16%。总之,IS2 通过提高干旱刺激再水合后的生理特性,增加了籽粒生长、产量和水分利用效率。