Abstract：
Sodium nitroprusside (SNP) is a potent nitric oxide (NO) donor that enhances plant tolerance to various abiotic stresses. This research aims to assess the effect of SNP application on rice seedlings subjected to individual and combined exposure to two abiotic stresses viz., low-temperature (LT) and chromium (Cr). Exposure to LT, Cr, and LT+Cr caused severe oxidative damage by stimulating greater production and accumulation of reactive oxygen species (ROS) leading to lipid peroxidation and cell membrane instability. The combined LT+CR stress more intensly increased the cellular oxidative stress and excessive Cr uptake that in turn deteriorated the chlorophyll pigments and photosynthesis, as well as effected the level of tetrapyrrole biosynthesis in rice plants. The reduction in rice seedling growth was more obvious under LT+Cr treatment than their individual effects. The exogenous application of SNP diminished the toxic impact of LT and Cr stress. This was attributed to the positive role of SNP in regulating the endogenous NO levels, free amino acids (FAAs) contents, tetrapyrrole biosynthesis and antioxidants. Consequently, SNP-induced NO decreased photorespiration, ROS generation, lipid peroxidation, and electrolyte leakage. Moreover, exogenous SNP diminished the Cr uptake and accumulation by modulating the ionic homeostasis and strengthening the heavy metals detoxification mechanism, thus improving plant height, biomass and photosynthetic indexes. Essentially, SNP boosts plant tolerance to LT and Cr stress by regulating antioxidants, detoxification mechanism, and the plant\'s physio-biochemical. Hence, applying SNP is an effective method for boosting rice plant resilience and productivity in the face of escalating environmental stresses and pollutants.
摘要：
硝普钠（SNP）是一种有效的一氧化氮（NO）供体，可增强植物对各种非生物胁迫的耐受性。这项研究旨在评估SNP应用对水稻幼苗的影响，这些水稻幼苗受到两种非生物胁迫的影响。,低温（LT）和铬（Cr）。暴露于LT,Cr,LT+Cr通过刺激活性氧(ROS)的更多产生和积累导致脂质过氧化和细胞膜不稳定而引起严重的氧化损伤。LT+CR联合胁迫更强烈地增加了细胞的氧化应激和过量的Cr吸收，进而恶化了叶绿素色素和光合作用。以及影响水稻植物中四吡咯的生物合成水平。LT+Cr处理下水稻幼苗生长的减少比它们的个体效应更明显。SNP的外源施用减少了LT和Cr胁迫的毒性影响。这归因于SNP在调节内源性NO水平方面的积极作用，游离氨基酸（FAA）含量，四吡咯生物合成和抗氧化剂。因此,SNP诱导的NO降低光呼吸，ROS生成，脂质过氧化，和电解质泄漏。此外，外源SNP通过调节离子稳态和加强重金属解毒机制来减少Cr的吸收和积累，从而提高植物高度，生物量和光合指标。本质上,SNP通过调节抗氧化剂提高植物对LT和Cr胁迫的耐受性，解毒机制，和植物的生理生化。因此，在环境胁迫和污染物不断升级的情况下，应用SNP是提高水稻抗逆性和生产力的有效方法。
