外源NO对Cu胁迫下番茄Cu的亚细胞分布和化学形态的影响

采用营养液培养方法，研究外源NO供体硝普钠(SNP)处理对50 μmol·L^-1Cu²⁺胁迫下番茄幼苗Cu的亚细胞分布和化学形态的影响.结果表明： Cu胁迫下，番茄幼苗的生物量和株高显著降低33.7%和23.1%，外源NO能够显著缓解这种抑制作用，但各器官中Cu的含量和累积量仍显著升高.Cu胁迫下，番茄幼苗各器官的Cu含量和累积量大小依次为根系>叶片>茎>叶柄，幼苗根系吸收的Cu向地上部的转运大幅降低，外源NO只能缓解而不能消除这种作用.外源NO可以使Cu胁迫下幼苗各器官的液泡和细胞壁中Cu含量显著上升，细胞器中Cu含量降低，从而减轻过多Cu对胞质生理生化代谢的伤害，增强组织细胞对Cu的耐性.外源NO可以提高番茄幼苗根系中醋酸提取态铜（F_HAc）、茎中氯化钠提取态铜（F_NaCl）、叶柄中F_HAc、叶片中乙醇提取态铜（F_E）和F_NaCl的含量，降低水溶态铜（F_W）的含量与比例，以降低过多铜的生物毒性.

Effects of exogenous nitric oxide on the subcellular distribution and chemical forms of copper in tomato seedlings under copper stress

A nutrient solution culture experiment was conducted to study the effects of exogenous NO donor (sodium nitroprusside) on the subcellular distribution and chemical form of copper (Cu) in tomato seedlings under the stress of 50 μmol·L^-1 of Cu²⁺ (CuCl₂). Under this stress, the biomass and plant height of tomato seedlings decreased by 33.7% and 23.1%, respectively. Exogenous NO alleviated this inhibition effect significantly, but the Cu concentration and accumulation in the seedling organs still had a significant increase. Under the Cu stress, the Cu concentration and accumulation in the seedling organs were in the order of root > leaf > stem > petiole. Exogenous NO limited the absorbed Cu transferred from root to shoot, but could not remove this translocation. Exogenous NO increased the Cu concentration in vacuole and cell wall significantly, and decreased the Cu concentration in organelle, which lessened the damage of Cu on the regular metabolic balance in cytoplasm and increased the tolerance of organelle against Cu. Exogenous NO increased the acetic acid extractable Cu (F_HAc) in root, sodium chloride extractable Cu (F_NaCl) in stem, F_HAc in petiole, and ethanol extractable Cu (F_E) and F_NaCl in leaf, while decreased the concentration and distribution of water-extractable Cu (F_W) in different organs, which efficiently reduced the bio-toxicity of excessive copper.