Dou Jianhua, Tang Zhongqi, Yu Jihua, Wang Guangzheng, An Wangwang, Zhang Yonghai, Yang Qing
College of Horticulture, Gansu Agricultural University, Lanzhou, 730070, China.
State Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, 730070, China.
Sci Rep. 2025 Feb 12;15(1):5172. doi: 10.1038/s41598-025-88565-5.
Saline-alkali stress is a major abiotic stress factor that adversely affects the growth, development, and yield of crops by disrupting ion homeostasis, osmotic balance, and metabolic processes. This study was designed to explore the alleviating effect of melatonin on the growth and development of tomato plants under saline-alkali stress conditions and to screen for optimal concentrations to alleviate the stress. Tomato variety 'Condine Red' was used as the test material, and a total of six treatments were designed including no saline-alkali stress and no melatonin spray as control (CK), and foliar spraying of 0, 50, 100, 150, and 200 µmol·L melatonin under saline-alkali stress (75 mmol·L), which were used to determine the growth and photosynthetic characteristics of tomato plants. The results showed that saline-alkali stress significantly inhibited plant height, stem diameter, root activity and biomass accumulation, significantly reduced the chlorophyll content of tomato leaves and the efficiency of photosynthetic electron transfer from primary quinone receptor QA to secondary quinone receptor QB, and caused significant deformation of the fast chlorophyll fluorescence induced kinetic curve (OJIP), inhibiting photosynthesis. Exogenous melatonin could improve tomato tolerance to saline-alkali stress, and the effect depended on the concentration. In this experiment, treatment with 100 µmol·L melatonin showed the strongest positive effect on the growth of tomato plants under saline-alkali stress according to the comprehensive evaluation of principal components. In addition, changes in photosynthetic chlorophyll fluorescence parameters and chlorophyll fluorescence induction curves after melatonin treatment highlighted that melatonin could improve the response of the photosynthetic system to saline-alkali stress by enhancing quenching of excess excitation energy and protecting the photosynthetic electron transport system. Collectively, exogenous melatonin pretreatment increased root activity, chlorophyll content and improved photosystem processes, thereby alleviating tomato growth under saline-alkali stress. The results of this study lay the foundation for the practical application of melatonin in saline-alkali stress.
盐碱胁迫是一种主要的非生物胁迫因素，通过破坏离子稳态、渗透平衡和代谢过程，对作物的生长、发育和产量产生不利影响。本研究旨在探讨褪黑素对盐碱胁迫条件下番茄植株生长发育的缓解作用，并筛选缓解胁迫的最佳浓度。以番茄品种‘康地红’为试验材料，共设计了6个处理，包括无盐碱胁迫且不喷施褪黑素作为对照（CK），以及在盐碱胁迫（75 mmol·L）下叶面喷施0、50、100、150和200 µmol·L褪黑素，用于测定番茄植株的生长和光合特性。结果表明，盐碱胁迫显著抑制了株高、茎粗、根系活力和生物量积累，显著降低了番茄叶片的叶绿素含量以及光合电子从初级醌受体QA向次级醌受体QB的传递效率，并导致快速叶绿素荧光诱导动力学曲线（OJIP）发生显著变形，抑制了光合作用。外源褪黑素可以提高番茄对盐碱胁迫的耐受性，且效果取决于浓度。在本试验中，根据主成分综合评价，100 µmol·L褪黑素处理对盐碱胁迫下番茄植株的生长表现出最强的正向效应。此外，褪黑素处理后光合叶绿素荧光参数和叶绿素荧光诱导曲线的变化突出表明，褪黑素可以通过增强过剩激发能的淬灭和保护光合电子传递系统来改善光合系统对盐碱胁迫的响应。总的来说，外源褪黑素预处理提高了根系活力、叶绿素含量并改善了光合系统过程，从而缓解了盐碱胁迫下番茄的生长。本研究结果为褪黑素在盐碱胁迫中的实际应用奠定了基础。
