在过去的几十年中,人为活动的增加导致土壤中镉含量的逐渐增加,which,由于其在土壤中的高流动性,Cd在植物体内的积累严重威胁着动物和人类的健康。已知包括褪黑激素(Mel)和油菜素类固醇(BR)的植物激素提供对各种非生物胁迫的耐受性。在这项工作中,研究了Mel和BR联合和单独外源施用对樱桃番茄植株Cd胁迫的作用。Cd胁迫通过诱导氧化应激和降低根和芽对K的吸收来显着降低番茄的生长。Mel和BR的联合应用通过(i)减少芽中Cd的积累来减少番茄中Cd的有害影响;(ii)增加不同抗氧化剂(SOD,CAT,APX,GR);(iii)触发与Cd液泡隔离相关的基因的较高表达(Na/H交换,SlNHX1;天然抗性相关巨噬细胞蛋白6,SlNRAMP6),和Cd的运输和解毒(重金属相关3,SlHMA3;植物镉抗性2,SlPCR2);(iv)改善植物K稳态和根和茎中的含量。后一种性状与K+通透性外向整流通道(SlGORK3)基因表达降低有关,Cd胁迫下高亲和力钾转运蛋白5(SIHAK5)的转录上调。Mel和BR的单独应用显示了通过调节抗氧化活性对番茄生长和Cd耐受性的组织特异性调节,K+吸收,Cd吸收,以及从根到芽的转运及其内源含量。褪黑素本身对提高芽中Cd的耐受性更有效,而有益的BR效应在根中更明显,它们的联合应用对两种组织都有效。一起来看,报道的结果表明,Mel和BR在樱桃番茄植物中对Cd耐受性的组织特异性调节,并证明了MelBR联合处理作为减少Cd积累并减轻其对植物生长的负面影响的实用工具的效率。
Increased anthropogenic activities over the last decades have led to a gradual increase in cadmium content in the soil, which, due to its high mobility in soil, makes Cd accumulation in plants a serious threat to the health of animals and humans. Plant hormones including melatonin (Mel) and brassinosteroids (BR) are known to provide tolerance against various abiotic stresses. In this work, the role of combined and separate exogenous application of Mel and BR on Cd stress in cherry tomato plants was examined. Cd stress significantly reduced tomato growth by inducing oxidative stress and reduced K+ uptake in roots and shoots. Combined application of Mel and BR reduced detrimental effects of Cd in tomato by (i) reducing Cd accumulation in the shoot; (ii) increasing the activities of different antioxidants (SOD, CAT, APX, GR); (iii) triggering higher expression of genes relating to Cd vacuolar sequestration (Na+/H+ EXCHANGER, SlNHX1; NATURAL RESISTANCE-ASSOCIATED MACROPHAGE PROTEIN 6, SlNRAMP6), and Cd transport and detoxification (HEAVY-METAL-ASSOCIATED 3, SlHMA3; PLANT CADMIUM RESISTANT 2, SlPCR2); and (iv) improving plant K+ homeostasis and contents in root and shoot. The latter trait was associated with the reduced gene expression of K+-permeable outward rectifying channel (SlGORK3), and transcriptional upregulation of high affinity potassium transporter 5 (SIHAK5) under Cd stress. A separate application of Mel and BR showed tissue-specific regulation of tomato growth and Cd tolerance by regulating antioxidant activities, K+ uptake, Cd uptake, and translocation from root to shoot and their endogenous contents. Melatonin per se was more effective in improving Cd tolerance in shoot while beneficial BR effects were more pronounced in roots, and their combined application was effective in both tissues. Taken together, reported results show tissue-specific regulation of Cd tolerance by Mel and BR in cherry tomato plants and demonstrate the efficiency of combined Mel + BR treatment as a practical tool to reduce Cd accumulation and mitigate its negative effects on plant growth.