College of Coastal Agriculture Sciences, Guangdong Ocean University, Zhanjiang, Guangdong 524088, China; Agricultural College of Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang 163000, China; Shenzhen Research Institute of Guangdong Ocean University, Shenzhen, Guangdong 518108, China.
College of Coastal Agriculture Sciences, Guangdong Ocean University, Zhanjiang, Guangdong 524088, China; Agricultural College of Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang 163000, China.
Ecotoxicol Environ Saf. 2021 Sep 1;220:112369. doi: 10.1016/j.ecoenv.2021.112369. Epub 2021 Jun 2.
Soil salinization seriously restricts the growth and yield of soybeans. However, little information is available on the early growth stages of soybeans which are subjected to the gibberellin biosynthesis inhibitor, prohexadione-calcium (Pro-Ca). This study aimed to investigate the effects of exogenous Pro-Ca on saline-alkali stress-induced damages to photosynthesis and antioxidant defenses in soybean (Glycine max L.) seedlings. At the V3 growth stage, salt-tolerant genotype Hefeng 50 (HF50) and salt-sensitive genotype Kenfeng 16 (KF16) were subjected to 110 mmol L mixed saline-alkali stress respectively, and then 100 mg L Pro-Ca was sprayed on the leaves. Our results showed that saline-alkali stress accelerated the degradation of thylakoids, inhibited chlorophyll synthesis, reduced shoot dry weight, electron transfer rate (ETR), and peroxidase (POD) activity, the concentration of ascorbic acid (AsA) and soluble sugar, but enhanced the concentration of proline, hydrogen peroxide (HO) and the rate of superoxide radical (O) generation. Additionally, saline-alkali stress induced a lower decrease of the net photosynthetic rate (P), potential activity of PSII (F/F), and maximum quantum yield of PSII (F/F) in salt-tolerant HF50 than in salt-sensitive KF16. Nevertheless, foliar spraying of exogenous Pro-Ca increased the chlorophyll content, P, F/F, and F/F. These results were more prominent when Pro-Ca was applied to KF16 under saline-alkali conditions. Furthermore, exogenous application of Pro-Ca retarded the degradation of thylakoids, increased the ETR and the accumulation of AsA, soluble sugar, and proline, activated the activities of superoxide dismutase (SOD), catalase (CAT), and POD, and decreased the concentration of malondialdehyde (MDA), electrolyte leakage (EL), O, and HO. These results indicated that Pro-Ca could effectively protect soybean seedlings against damage from saline-alkali stress by regulating seedling phenotype, photosynthetic apparatus, antioxidant defense, and osmoregulation.
土壤盐渍化严重限制了大豆的生长和产量。然而，关于赤霉素生物合成抑制剂丙环唑钙（Pro-Ca）处理下大豆早期生长阶段的信息很少。本研究旨在探讨外源 Pro-Ca 对盐堿胁迫下大豆（Glycine max L.）幼苗光合作用和抗氧化防御的影响。在 V3 生长阶段，耐盐基因型荷丰 50（HF50）和盐敏感基因型垦丰 16（KF16）分别受到 110 mmol·L-1 的混合盐堿胁迫，然后在叶片上喷施 100 mg·L-1 的 Pro-Ca。结果表明，盐堿胁迫加速了类囊体的降解，抑制了叶绿素的合成，降低了地上部干重、电子传递速率（ETR）和过氧化物酶（POD）活性，降低了抗坏血酸（AsA）和可溶性糖的浓度，但增加了脯氨酸、过氧化氢（HO）和超氧自由基（O）生成速率的浓度。此外，盐堿胁迫诱导耐盐 HF50 的净光合速率（P）、PSII 潜在活性（F/F）和 PSII 最大量子产量（F/F）的下降幅度低于盐敏感 KF16。然而，叶面喷施外源 Pro-Ca 增加了叶绿素含量、P、F/F 和 F/F。在外源 Pro-Ca 处理下，盐堿条件下的 KF16 表现更为明显。此外，外源 Pro-Ca 延缓了类囊体的降解，增加了 ETR 和 AsA、可溶性糖和脯氨酸的积累，激活了超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）的活性，降低了丙二醛（MDA）、电解质渗漏（EL）、O 和 HO 的浓度。这些结果表明，Pro-Ca 通过调节幼苗表型、光合器官、抗氧化防御和渗透调节，能有效保护大豆幼苗免受盐堿胁迫的伤害。
