外源亚精胺对盐碱胁迫下番茄幼苗根系线粒体功能的影响

为探讨外源亚精胺(Spd)对盐碱胁迫下番茄根系线粒体功能的影响，采用水培法，以耐性不同的两个番茄品种‘金棚朝冠’（耐盐型）和‘中杂9号’（敏感型）为试材，通过模拟盐碱生态条件(NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃=1∶9∶9∶1)，结合叶面喷施外源0.25 mmol·L^-1Spd，研究盐碱胁迫8 d后Spd对番茄幼苗根系形态和根系线粒体功能的影响.结果表明： 盐碱胁迫下，两个品种番茄根系线粒体内H₂O₂和丙二醛（MDA）含量增加，线粒体膜通透性明显增大，流动性降低，膜电位、线粒体内细胞色素c/a(Cyt c/a)吸光度比值、膜H⁺-ATPase活性显著下降，使线粒体受到不同程度的损伤，从而抑制根系生长，且‘金棚朝冠’的上述指标变化幅度均小于‘中杂9号’.盐碱胁迫下，喷施外源Spd处理的两个品种根系线粒体H₂O₂和MDA含量显著降低，膜通透性减小、流动性增加，膜电位、线粒体内Cyt c/a吸光度比值、膜H⁺-ATPase活性显著提高，可有效缓解盐碱胁迫对番茄幼苗根系线粒体的伤害作用，且这种缓解作用在‘中杂9号’上的表现效果更佳.

Effects of exogenous spermidine on mitochondrial function of tomato seedling roots under salinity alkalinity stress.

Two cultivars of tomato (Solanum lycopersicum, cvs. ‘Jinpengchaoguan’ and ‘Zhongza No. 9’, with the former being more tolerant to saline alkaline stress) seedlings grown hydroponically were subjected to salinity alkalinity stress condition (NaCl:Na₂SO₄:NaHCO₃:Na₂CO₃=1:9:9:1) without or with foliar application of 0.25 mmol·L^-1spermidine (Spd), and the root morphology and physiological characteristics of mitochondrial membrane were analyzed 8 days after treatment, to explore the protective effects of exogenous Spd on mitochondrial function in tomato roots under salinity alkalinity stress. The results showed that the salinity alkalinity stress increased the concentrations of both mitochondrial H₂O₂ and MDA as well as the mitochondrial membrane permeability in the roots of the two cultivars, while it decreased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H⁺-ATPase activity, which impaired the mitochondria and therefore inhibited the root growth; and these effects were more obvious in ‘Zhongza No. 9’ than in ‘Jinpengechaoguan’. Under the salinity alkalinity stress, foliar application Spd could effectively decrease the concentrations of mitochondrial H₂O₂ and MDA and mitochondrial membrane permeability, while increased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H⁺-ATPase activity. These results suggested that exogenous Spd could effectively mitigate the damage on mitochondria induced by salinity alkalinity stress, and the alleviation effect was more obvious in ‘Zhongza No. 9’ than in ‘Jinpengchaoguan’.