Abstract

In the current work, the influence of indole-3-acetic acid (IAA; 10^–5 M) and 28-homobrassinolide (HBL; 10^–8 M) alone or in combination was explored in Solanum melongena L. seedlings treated with sodium chloride (NaCl). The NaCl at different concentrations (5 mM and 15 mM) reduced growth attributes, photosynthetic pigments as well as photosynthesis, and enhanced the dark respiratory rate, and these effects were accompanied with Na⁺ and reactive oxygen species (ROS) accumulation in leaf tissues. Moreover, NaCl reduced the proficiency of PS II with the increasing doses of selected stress which is apparent from the declined values of F_v/F_m (Phi_P₀), Ѱ₀ (Psi_0), ϕ_E0 (Phi_E0) and PI_ABS, and augmented values of energy fluxes: ABS/RC, ET₀/RC, TR₀/RC and DI₀/RC. The NaCl treatment caused substantial reduction in nitrate and nitrite contents, activities of nitrate reductase, nitrite reductase, glutamine synthetase and glutamate synthase, and increased ammonium content and glutamate dehydrogenase activity. Enhanced level of ROS, i.e. superoxide radical (O₂^•−) and hydrogen peroxide (H₂O₂) under NaCl stress amplified the lipid peroxidation product malondialdehyde (MDA), in spite of considerable upsurge in performance of superoxide dismutase, peroxidase, catalase, glutathione-S-transferase enzymes and amount of non-protein thiol, cysteine and proline. Exogenous supplementation of IAA and HBL considerably assuaged the NaCl-induced collapse in growth attributes by manipulating the structural and functional features of photosynthetic apparatus. The ameliorating effect of IAA and HBL, in combination, was due to (1) substantial decrease in Na⁺ accumulation, (2) improvement in PS II efficiency and nitrogen metabolism and (3) reduced oxidative damage in S. melongena L. due to stimulatory response of antioxidants that keeps the level of oxidants under limit in the seedlings. Thus, the overall results campaigned that IAA and HBL act synergistically to overcome the toxic effects that NaCl had on S. melongena L. seedlings.

中文翻译：

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吲哚乙酸与高油菜素内酯的协同作用减轻NaCl诱导的茄子幼苗的毒性

摘要

在目前的工作中，在用氯化钠处理的茄茄 中探索了吲哚-3-乙酸（IAA； 10 – ⁵  M）和28-高油菜素内酯（HBL； 10 ^{– 8} M）的影响。 （NaCl）。不同浓度（5 mM和15 mM）的NaCl降低了生长属性，光合色素以及光合作用，并增强了黑暗呼吸频率，这些作用伴随有Na ⁺和活性氧（ROS）在叶片组织中的积累。此外，NaCl随所选应力剂量的增加而降低PS II的水平，这从F _v / F _m的下降值可以明显看出（Phi_P ₀），Ѱ ₀（Psi_0），φ _E0（Phi_E0）和PI _ABS，和能量通量的增加值：ABS / RC，ET ₀ / RC，TR ₀ / RC和DI ₀ / RC。NaCl处理导致硝酸盐和亚硝酸盐含量的大幅降低，硝酸盐还原酶，亚硝酸盐还原酶，谷氨酰胺合成酶和谷氨酸合酶的活性，并增加了铵含量和谷氨酸脱氢酶的活性。ROS含量提高，即超氧自由基（O ₂ ^•-）和过氧化氢（H ₂ O ₂在NaCl胁迫下，尽管超氧化物歧化酶，过氧化物酶，过氧化氢酶，谷胱甘肽-S-转移酶和非蛋白质硫醇，半胱氨酸和脯氨酸的含量大幅增加，但脂质过氧化产物丙二醛（MDA）仍被放大。通过操纵光合装置的结构和功能特征，IAA和HBL的外源补充大大缓解了NaCl诱导的生长特性崩溃。结合起来，IAA和HBL的改善效果是由于（1）Na ⁺积累的显着降低，（2）PS II效率和氮代谢的改善以及（3）S中链球菌的氧化损伤减少。L.由于抗氧化剂的刺激性反应，使幼苗中的氧化剂含量保持在极限之下。因此，总体结果促使IAA和HBL协同发挥作用，以克服NaCl对S. melongena L.幼苗的毒性作用。