The objective of the present study was to assess the effects of exogenous application of 1 mM Jasmonic acid (JA), an endogenous plant growth regulator, on mitigation of oxidative and osmotic stresses caused by various levels of NaCl: none (0 mM), light (50 mM), moderate (150 mM), and severe (300 mM) in roselle (Hibiscus sabdariffa L.) seedlings. Salt stress without any change in leaf water content negatively affected seedlings growth from the aspect of plant height, root length, leaf morphological properties, plant biomass and levels of pigments, reducing sugars, starch, proteins and free amino acids, but accumulated higher levels of non-reducing sugars, total phenols, anthocyanins, flavonoids, proline and increased activities of both enzymatic and non-enzymatic antioxidants, such as ascorbate peroxidase (APX), pyrogallol peroxidase (PPX) and polyphenol oxidase (PPO). JA-treated seedlings exhibited a significant increase in growth parameters and activities of APX and PPX under salt stress, with hyper-accumulation of metabolite levels, but accumulated lower amounts of dry matter in roots and decreased the activity of PPO. These results clearly showed that exogenous JA treatment protected roselle seedlings against salt-induced damage through up-regulating the activity of H₂O₂-decomposing enzymes, osmoprotectants biosynthesis, and the accumulation of metabolites.

本研究的目的是评估外源施用1 mM茉莉酸（JA）（一种内生植物生长调节剂）对缓解各种水平的NaCl引起的氧化和渗透胁迫的影响：无（0 mM），轻（50 mM），中度（150 mM）和严重（300 mM）的玫瑰茄（Hibiscus sabdariffaL.）幼苗。从植物高度，根长，叶片形态特性，植物生物量和色素含量，还原糖，淀粉，蛋白质和游离氨基酸的含量等方面来看，盐胁迫没有改变叶片含水量，会对幼苗的生长造成不利影响，但累积的水分含量较高。非还原性糖，总酚，花青素，类黄酮，脯氨酸和酶促和非酶促抗氧化剂（例如抗坏血酸过氧化物酶（APX），邻苯三酚过氧化物酶（PPX）和多酚氧化酶（PPO））的活性增强。JA处理的幼苗在盐胁迫下表现出显着增加的APX和PPX生长参数和活性，代谢物水平过度积累，但在根部积累的干物质量减少，PPO活性降低。₂ O ₂分解酶，渗透保护剂的生物合成和代谢产物的积累。