Soil Science and Plant Nutrition Department, Agriculture Faculty, Harran University, Sanliurfa, Turkey.
Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tas., Australia; and School of Biological Science, University of Western Australia, Crawley, WA, Australia; and International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China.
Funct Plant Biol. 2024 Jan;51(1):NULL. doi: 10.1071/FP23060.
While ameliorating effects of melatonin (MT) on abiotic stress tolerance in plants are widely reported, the mechanism that underlies this process remains elusive. This work investigated mechanisms by which MT improved drought tolerance in pepper (Capsicum annuum ) plants. A foliar spray of 0.1mM MT treatment was applied to plants grown at 80% and 40% of full field capacity for 3days. Drought stress caused a significant decrease in plant dry weight, relative water content, leaf water potential, PSII efficiency (F v /F m ratio), chlorophyll, soluble protein, leaf and root nitrogen content. Drought increased hydrogen peroxide, malondialdehyde (MDA), nitrate, ammonium, free amino acids, soluble sugars, proline and glycine betaine. Drought also increased peroxidase (POD), glutathione S-transferase (GST) and catalase (CAT) activities, electrolyte leakage (EL) and methylglyoxal (MG). MT pre-treatment reduced oxidative stress and improved nitrogen metabolism by activating various enzymes such as nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthetase (GOGAT) and glutamine dehydrogenase (GDH) activities. It also activated enzymes related to the glyoxalase system (Gly I and Gly II) and decreased NO3 - , NH4 + and free amino acid content. Our study suggests a cost-effective and sustainable solution to improve crop productivity in water-limited conditions, by enhancing plant growth, photosynthesis and nitrogen content.
虽然褪黑素（MT）对植物非生物胁迫耐受性的改善作用已被广泛报道，但这一过程的机制仍不清楚。本研究旨在探究 MT 提高辣椒植株耐旱性的机制。在 80%和 40%田间持水量下生长的植株叶面喷施 0.1mM MT 处理 3 天。干旱胁迫导致植株干重、相对水含量、叶片水势、PSII 效率（F v /F m 比值）、叶绿素、可溶性蛋白、叶片和根氮含量显著下降。干旱增加了过氧化氢（H2O2）、丙二醛（MDA）、硝酸盐、铵、游离氨基酸、可溶性糖、脯氨酸和甘氨酸甜菜碱的含量。干旱还增加了过氧化物酶（POD）、谷胱甘肽 S-转移酶（GST）和过氧化氢酶（CAT）活性、电解质泄漏（EL）和甲基乙二醛（MG）的含量。MT 预处理通过激活硝酸还原酶（NR）、亚硝酸盐还原酶（NiR）、谷氨酰胺合成酶（GS）、谷氨酸合成酶（GOGAT）和谷氨酸脱氢酶（GDH）等各种酶，减轻了氧化应激，改善了氮代谢。它还激活了与乙醛酸循环系统（Gly I 和 Gly II）相关的酶，降低了 NO3 - 、NH4 + 和游离氨基酸的含量。我们的研究表明，通过提高植物生长、光合作用和氮含量，MT 预处理是一种经济有效的可持续解决方案，可在水分有限的条件下提高作物生产力。
