College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, China.
National Saline-tolerant Rice Technology Innovation Center, South China, Zhanjiang, China.
PLoS One. 2023 Mar 17;18(3):e0279192. doi: 10.1371/journal.pone.0279192. eCollection 2023.
Salt stress, as a principal abiotic stress, harms the growth and metabolism of rice, thus affecting its yield and quality. The tillering stage is the key growth period that controls rice yield. Prohexadione-calcium (Pro-Ca) can increase the lodging resistance of plants by reducing plant height, but its effects on rice leaves and roots at the tillering stage under salt stress are still unclear. This study aimed to evaluate the ability of foliar spraying of Pro-Ca to regulate growth quality at the rice tillering stage under salt stress. The results showed that salt stress reduced the tillering ability of the rice and the antioxidant enzyme activity in the roots. Salt stress also reduced the net photosynthetic rate (Pn), stomatal conductance (Gs) and intercellular CO2 concentration (Ci) of the rice leaves and increased the contents of osmotic regulatory substances in the leaves and roots. The application of exogenous Pro-Ca onto the leaves increased the tiller number of the rice under salt stress and significantly increased the photosynthetic capacity of the leaves. Additionally, it increased the activities of antioxidant enzymes and the AsA content. The contents of an osmotic regulation substance, malondialdehyde (MDA), and H2O2 in the leaves and roots also decreased. These results suggested that Pro-Ca can increase the tillering ability, photosynthetic capacity, osmotic adjustment substance content levels and antioxidant enzyme activity levels in rice and reduce membrane lipid peroxidation, thus improving the salt tolerance of rice at the tillering stage.
盐胁迫作为主要的非生物胁迫因素，会危害水稻的生长和代谢，从而影响其产量和品质。分蘖期是控制水稻产量的关键生长时期。调环酸钙（Pro-Ca）可以通过降低株高来增加植物的抗倒伏能力，但它对盐胁迫下水稻分蘖期叶片和根系的影响尚不清楚。本研究旨在评估叶面喷施 Pro-Ca 对盐胁迫下水稻分蘖期生长品质的调节能力。结果表明，盐胁迫降低了水稻的分蘖能力和根系中的抗氧化酶活性。盐胁迫还降低了水稻叶片的净光合速率（Pn）、气孔导度（Gs）和胞间 CO2 浓度（Ci），并增加了叶片和根系中渗透调节物质的含量。叶面喷施外源 Pro-Ca 增加了盐胁迫下水稻的分蘖数，显著提高了叶片的光合能力。此外，它还增加了抗氧化酶的活性和 AsA 的含量。叶片和根系中丙二醛（MDA）和 H2O2 的含量也降低了。这些结果表明，Pro-Ca 可以提高水稻的分蘖能力、光合能力、渗透调节物质含量和抗氧化酶活性，降低膜脂过氧化，从而提高水稻在分蘖期的耐盐性。
