Proline and sodium nitroprusside increase the tolerance of Physalis peruviana L. plants to water deficit through chemical priming

ABSTRACT Water deficit is the main cause of abiotic stress to which plants are susceptible, whether cultivated or those that are underexploited, such as Physalis peruviana L. Searching for tools that contribute to the management of water deficit in plants is fundamental for the maintenance of agriculture, especially in arid and semi-arid areas around the world. Thus, the objective of this study was to evaluate the effect of chemical priming with proline and sodium nitroprusside as promoters of increased tolerance to water deficit in P. peruviana plants. Plants grown under well hydrated conditions (FC of 70±5%) were sprayed with proline (10 and 20 mM) or sodium nitroprusside (25 and 50 μM) and evaluated after exposure to water deficit (FC of 20±5%). Plants cultivated under water deficit without pretreatment showed reductions in the variables of water relations, gas exchange and growth. Proline and sodium nitroprusside were effective in maintaining less negative water potential, contributing to improvements in gas exchange, such as CO2 assimilation, stomatal conductance and transpiration. Thus, it was possible to measure greater tolerance to water deficit in pretreated plants and, consequently, greater biomass accumulation. It appeard that pretreatment of proline and sodium nitroprusside can have a priming effect against water deficit in P. peruviana plants.摘要 水分亏缺是植物（无论栽培物种还是未充分开发利用的物种，如酸浆（Physalis peruviana L.））所面临的主要非生物胁迫。探寻可助力植物水分亏缺管理的技术手段，对维持全球农业生产至关重要，尤其在干旱与半干旱区域。本研究旨在评估以脯氨酸（proline）与硝普钠（sodium nitroprusside）作为诱导剂，通过化学引发提升酸浆植株水分亏缺耐受性的效果。将在充分供水条件（田间持水量（Field Capacity, FC）为70±5%）下培育的植株，分别喷施浓度为10 mM、20 mM的脯氨酸，或25 μM、50 μM的硝普钠，待其遭遇水分亏缺胁迫（FC为20±5%）后开展相关指标测定。未经过预处理且处于水分亏缺环境的植株，其水分关系、气体交换及生长相关指标均出现显著下降。脯氨酸与硝普钠可有效维持水势的负向程度更低，同时改善气体交换相关指标，包括二氧化碳同化速率、气孔导度与蒸腾速率。由此可见，经预处理的植株对水分亏缺的耐受性显著提升，生物量积累也随之增加。本研究证实，脯氨酸与硝普钠预处理可对酸浆植株产生抵御水分亏缺的引发效应（priming effect）。