Li Jun, Zhao Meiai, Liu Ligong, Guo Xinmei, Pei Yuhe, Wang Chunxiao, Song Xiyun
College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China.
College of Life Sciences, Qingdao Agricultural University, Qingdao 266109, China.
Plants (Basel). 2023 Jun 26;12(13):2456. doi: 10.3390/plants12132456.
This study aims to explore the impacts of exogenous sorbitol on maize seedlings under polyethylene glycol (PEG)-simulated drought stress. Six treatments were set: normal condition (CK), PEG (P), 10 mM sorbitol (10S), PEG plus 10 mM sorbitol (10SP), 100 mM sorbitol (100S) and PEG plus 100 mM sorbitol (100SP). Maize seedlings' growth under PEG-simulated drought stress was significantly inhibited and exogenous sorbitol largely alleviated this growth inhibition. The seedlings under 10SP treatment grew much better than those under P, 100S and 100SP treatments and no significant difference in growth parameters was observed between the control and 10S treatment. The seedlings treated with 10SP had higher contents of soluble sugar, soluble protein, proline, ascorbic acid (AsA), reduced glutathione (GSH), sorbitol and relative water content, higher activities of antioxidant enzymes and aldose reductase, but lower contents of malondialdehyde (MDA), HO and relative electrical conductivity than those treated with P, 100S and 100SP. qRT-PCR analysis showed that the transcript levels of genes encoding putative aldose reductase (AR) under P treatment were significantly up-regulated in sorbitol-applied treatments. Taken together, the results demonstrated that exogenous sorbitol application conferred drought tolerance to maize seedlings by up-regulating the expression levels of AR-related genes to enhance the accumulation of intracellular osmotic substances such as sorbitol and improve antioxidant systems to tone down the damage caused by drought stress.
本研究旨在探讨外源山梨醇对聚乙二醇（PEG）模拟干旱胁迫下玉米幼苗的影响。设置了6种处理：正常条件（CK）、PEG（P）、10 mM山梨醇（10S）、PEG加10 mM山梨醇（10SP）、100 mM山梨醇（100S）和PEG加100 mM山梨醇（100SP）。PEG模拟干旱胁迫显著抑制了玉米幼苗的生长，而外源山梨醇在很大程度上缓解了这种生长抑制。10SP处理下的幼苗生长状况明显优于P、100S和100SP处理下的幼苗，且对照和10S处理之间的生长参数未观察到显著差异。与P、100S和100SP处理的幼苗相比，10SP处理的幼苗具有更高的可溶性糖、可溶性蛋白、脯氨酸、抗坏血酸（AsA）、还原型谷胱甘肽（GSH）、山梨醇含量和相对含水量，更高的抗氧化酶和醛糖还原酶活性，但丙二醛（MDA）、H₂O₂含量和相对电导率更低。qRT-PCR分析表明，P处理下假定醛糖还原酶（AR）编码基因的转录水平在施用山梨醇的处理中显著上调。综上所述，结果表明，外源施用山梨醇可通过上调AR相关基因的表达水平，增强山梨醇等细胞内渗透物质的积累，并改善抗氧化系统，以减轻干旱胁迫造成的损害，从而赋予玉米幼苗耐旱性。
