The aim of this experiment was to investigate the exogenous application of salicylic acid (SA) on morpho-physiological and molecular characteristics of Impatiens walleriana plants grown under water deficit stress. Three levels of soil water contents (95, 85, and 75% of field capacity; FC) and three levels of SA (0, 1, and 2 mM) were applied on two impatient cultivars (‘Tempo’ and ‘Salmon’). The results showed that increasing water deficit stress negatively affected growth and flowering characteristics. On the contrary, the foliar application of SA reduced the adverse effect of water deficit stress and improved growth and ornamental plant attributes. Water deficit increased the amount of electrolyte leakage (EL), malondialdehyde (MDA), peroxidase (POD) and ascorbate peroxidase (APX) activities; and proline content. The expression of the gene encoding for Δ1-pyrroline-5-carboxylate synthetase (P5CS) was slightly increased under control treatment (95% FC + SA 0 mM) and then significantly increased at 75% FC and after the SA treatments. The expression pattern of P5CR (Δ1-pyrroline-5-carboxylate reductase gene) was similar to that of P5CS, with differences in terms of intensity. The application of SA reduced the amount of EL and MDA through increased antioxidant activities and water balance. Overall, the results of this study showed that ‘Salmon’ cultivar was able to tolerate drought stress conditions better than ‘Tempo.’ The application of 2 mM SA increased growth and physiological indices in drought-stressed impatient, mitigating the detrimental effects of water deficit in this important ornamental species.

该实验的目的是研究水杨酸（SA）在凤仙花形态生理和分子特性中的外源应用在缺水胁迫下生长的植物。在两个耐心品种（'Tempo'和'Salmon'）上施用了三个水平的土壤水分（分别为田间持水量的95％，85％和75％； FC）和三个水平的SA（0、1、2 mM）。结果表明，水分亏缺胁迫的增加对生长和开花特性产生负面影响。相反，叶面喷施SA减少了水分亏缺胁迫的不利影响，并改善了生长和观赏植物的特性。缺水增加了电解质泄漏（EL），丙二醛（MDA），过氧化物酶（POD）和抗坏血酸过氧化物酶（APX）的活性；和脯氨酸含量。编码Δ1-吡咯啉-5-羧酸合成酶（P5CS）的基因的表达）在对照处理（95％FC + SA 0 mM）下略有增加，然后在75％FC和SA处理后显着增加。P5CR（Δ1-吡咯啉-5-羧酸还原酶基因）的表达模式与P5CS相似，但强度不同。SA的应用通过增加抗氧化剂活性和水平衡减少了EL和MDA的含量。总体而言，这项研究的结果表明，“ Salmon”品种比“ Tempo”品种具有更好的耐旱性。2 mM SA的施用增加了干旱胁迫下的不耐烦的生长和生理指标，从而减轻了这一重要观赏物种中水分亏缺的不利影响。