硫化氢对低温胁迫下甜樱桃柱头和子房线粒体功能的影响

为探索低温胁迫下外源硫化氢(H₂S)对甜樱桃花的柱头和子房线粒体功能的影响,本研究以甜樱桃品种‘早大果’花枝为试材,在-2 ℃低温下喷施0.05 mmol·L^-1硫氢化钠(NaHS,H₂S供体)和15 μmmol·L^-1 次牛磺酸(HT、H₂S清除剂),测定柱头和子房线粒体中活性氧、抗氧化酶和线粒体膜通透性转换孔(MPTP)开放程度、膜流动性、膜电位和细胞色素(Cyt c/a)比值变化。结果表明: 低温胁迫导致线粒体内过氧化氢(H₂O₂)和丙二醛(MDA)含量显著增加,线粒体MPTP明显增大,膜流动性降低,膜电位和线粒体Cyt c/a吸光度比值、膜H⁺-ATPase活性显著下降,线粒体结构受到损伤。低温胁迫下,外施0.05 mmol·L^-1 NaHS可显著降低低温胁迫下柱头和子房线粒体H₂O₂和MDA含量,在较长时间内维持较高的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性,减小线粒体MPTP开放程度,增强线粒体膜流动性,提高线粒体膜电位、Cyt c/a值和膜H⁺-ATPase活性;NaHS清除剂HT则抵消NaHS对上述参数的影响。综上所述,外源H₂S可以提高低温胁迫下甜樱桃柱头和子房线粒体抗氧化酶活性,减少H₂O₂和MDA积累,提高膜H⁺-ATPase活性,稳定线粒体膜结构和功能,进而缓解低温胁迫对花器官的伤害。

Effects of hydrogen sulfide on mitochondrial function in sweet cherry stigma and ovary under low temperature stress

To investigate the effects of H₂S on mitochondrial functions under low temperature stress, we analyzed the effects of 0.05 mmol·L^-1 NaHS and 15 μmmol·L^-1 HT (hypotaurine and H₂S scavenger) on mitochondria antioxidant enzyme activities and mitochondrial permeability transition pore, mitochondrial membrane fluidity, mitochondrial membrane potential, Cyt c/a ratio and H⁺-ATPase activity in sweet cherry stigma and ovary with sweet cherry variety Zaodaguo under -2 ℃ low temperature stress. The results showed that low temperature stress increased the concentrations of mitochondrial H₂O₂ and MDA, enhanced the mitochondrial membrane permeability, but decreased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H⁺-ATPase acti-vity. Application of NaHS at 0.05 mmol·L^-1 could effectively reduce the concentrations of H₂O₂ and MDA, and keep higher activities of SOD, POD and CAT of mitochondrial for longer time. Furthermore, application of 0.05 mmol·L^-1 NaHS could decrease mitochondrial membrane permeability while increase mitochondrial membrane fluidity, membrane potential, Cyt c/a and H⁺-ATPase activity in stigma and ovary under low temperature stress. The effects of NaHS were completely offset by HT addition. The results suggested that exogenous H₂S could alleviate the oxidative damage on stigma and ovary stress through decreasing H₂O₂ accumulation, regulating mitochondria antioxidant system, increasing H⁺-ATPase activity, and mitigating mitochondria function under low temperature.