Abstract：
Arsenic (As) poses a significant environmental threat as a metalloid toxin, adversely affecting the health of both plants and animals. Strigolactones (SL) and nitric oxide (NO) are known to play crucial roles in plant physiology. Therefore, the present experiment was designed to investigate the potential cumulative role of SL (GR24-0.20 μM) and NO (100 μM) in mitigating the adverse effect of AsV (53 μM) by modulating physiological mechanisms in two genotypes of tomato (Riogrand and Super Strain 8). A sample randomized design with four replicates was used to arrange the experimental pots in the growth chamber. 45-d old both tomato cultivars under AsV toxicity exhibited reduced morphological attributes (root and shoot length, root and shoot fresh weight, and root and shoot dry weight) and physiological and biochemical characteristics [chlorophyll (Chl) a and b content, activity of δ-aminolevulinic acid dehydratase activity (an enzyme responsible for Chl biosynthesis), and carbonic anhydrase activity (an enzyme responsible for photosynthesis), and enhanced Chl degradation, overproduction of reactive oxygen species (ROS) and lipid peroxidation due to enhanced malondialdehyde (MDA) content. However, the combined application of SL and NO was more effective in enhancing the tolerance of both varieties to AsV toxicity compared to individual application. The combined application of SL and NO improved growth parameters, biosynthesis of Chls, NO and proline. However, the combined application significantly suppressed cellular damage by inhibiting MDA and overproduction of ROS in leaves and roots, as confirmed by the fluorescent microscopy study and markedly upregulated the antioxidant enzymes (catalase, peroxidase, superoxide dismutase, ascorbate dismutase and glutathione reductase) activity. This study provides clear evidence that the combined application of SL and NO supplementation significantly improves the resilience of tomato seedlings against AsV toxicity. The synergistic effect of SL and NO was confirmed by the application of cPTIO (an NO scavenger) with SL and NO. However, further molecular studies could be imperative to conclusively validate the simultaneous role of SL and NO in enhancing plant tolerance to abiotic stress.
摘要：
砷（As）作为类金属毒素对环境构成重大威胁，对植物和动物的健康都有不利影响。已知Strigolactone（SL）和一氧化氮（NO）在植物生理学中起关键作用。因此,本实验旨在研究SL（GR24-0.20μM）和NO（100μM）在减轻AsV（53μM）的不利影响中的潜在累积作用，通过调节两种基因型番茄（Riogrand和SuperStrain8）的生理机制。使用具有四个重复的样品随机化设计将实验盆布置在生长室中。在AsV毒性下的45天龄的两个番茄品种均表现出降低的形态属性（根和茎长，根和芽的鲜重，和根和芽干重）和生理生化特性[叶绿素（Chl）a和b含量，δ-氨基乙酰丙酸脱水酶活性（一种负责Chl生物合成的酶）的活性，和碳酸酐酶活性（负责光合作用的酶），并增强了Chl降解，由于丙二醛（MDA）含量增加，活性氧（ROS）和脂质过氧化过量产生。然而,与单独施用相比，SL和NO的联合施用更有效地增强了两个品种对AsV毒性的耐受性。SL和NO的联合应用改善了生长参数，Chls的生物合成，NO和脯氨酸。然而,联合应用通过抑制叶片和根部MDA和ROS的过量产生来显著抑制细胞损伤，如荧光显微镜研究所证实的，并显著上调了抗氧化酶(过氧化氢酶，过氧化物酶,超氧化物歧化酶,抗坏血酸歧化酶和谷胱甘肽还原酶）活性。这项研究提供了明确的证据，表明SL和NO的组合施用显着提高了番茄幼苗对AsV毒性的抵抗力。SL和NO的协同作用通过cPTIO(NO清除剂)与SL和NO的应用得到证实。然而,进一步的分子研究可能必须最终验证SL和NO在增强植物对非生物胁迫的耐受性中的同时作用。
