H_2S对低温胁迫下甜樱桃柱头和子房AsA-GSH循环的响应

Effects of H_2S on Ascorbate-glutathione Cycle in Sweet Cherry Stigma and Ovary Under Low Temperature Stress

为了探究H_2S对甜樱桃花器官低温伤害的缓解机理,以甜樱桃品种早大果为试材,分析了不同浓度H_2S供体NaHS对低温胁迫下甜樱桃柱头和子房AsA-GSH循环系统的影响。结果表明,喷施0.02、0.05、0.1 mmol·L^(-1)的NaHS均可降低低温胁迫下甜樱桃柱头和子房超氧阴离子(O_2^-)、过氧化氢(H_2O_2)、丙二醛(MDA)含量,显著提高还原型抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量(P<0.05),降低氧化型抗坏血酸(DHA)和氧化型谷胱甘肽(GSSG)含量,使AsA/DHA和GSH/GSSG比值显著升高(P<0.05),以0.05 mmol·L^(-1)NaHS效果最显著;0.02、0.05、0.1 mmol·L^(-1)的NaHS均显著提高低温胁迫下柱头和子房AsA-GSH循环中抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)、单脱氢抗坏血酸还原酶(MDAR)、谷胱甘肽还原酶(GR)、谷胱甘肽过氧化物酶(GPX)和谷胱甘肽-S-转移酶(GST)的活性(P<0.05),以0.05 mmol·L^(-1)NaHS提高上述酶活性的幅度最大。NaHS的浓度大于0.2 mmol·L^(-1)不再提高低温胁迫下AsA-GSH循环效率;低温胁迫下添加NaHS的同时添加H_2S清除剂HT可解除H_2S的效果。综上所述,喷施适量外源H_2S可有效降低低温胁迫下O_2^-、H_2O,和MDA积累,提高AsA-GSH循环效率,减轻低温对甜樱桃柱头和子房的氧化伤害。本研究结果为明确H_2S缓解甜樱桃花器官低温伤害作用机制以及生产上花期低温伤害预防提供了理论依据。

To investigate the mitigation mechanism of H_2S on the low temperature injury of sweet cherry organ,effect of different concentrations of NaHS that is donor of H_2S on AsA-GSH circulatory system in sweet cherry stigma and ovary under low temperature stress were analyzed with sweet cherry variety Zaodaguo.The results showed that spraying 0.02,0.05 and 0.1 mmol·L（-1） NaHS could reduce the contents of superoxide anion（O_2）,hydrogen peroxide（H_2O_2） and malondialdehyde（MDA） in sweet cherry stigma and ovary under low temperature stress,increase ascorbate（AsA） and reduced glutathione（GSH）,dehydroascorbate（DHA） and oxidized glutathione（GSSG） contents,which resulted in the increase of the ratios of AsA/DHA and GSH/GSSG prominently.The NaHS concentration of 0.05 mmol·L（-1） was optimal.Meanwhile,the treatments of 0.02,0.05,0.1 mmol·L（-1） NaHS also promoted the activities of ascorbate peroxidase（APX）,dehydroascorbate reductase（DHAR）,monodehydroascorbate reductase（MDAR）,GSH-dependent glutathione reductase（GR）,glutathione-S-transferases（GST） and glutathione peroxidase（GPX） in sweet cherry stigma and ovary（P0.05）,while the effect of 0.05 mmol·L（-1） NaHS treatment was the largest to increase the activity of enzyme.High concentration of NaHS（0.2mmol·L（-1）） treatments did not improve the efficiency of AsA-GSH cycle under low temperature stress,and the effect of H_2S could be removed by adding NaHS and H_2S scavenger HT under low temperature stress.In conclusion,spraying proper amount of H_2S could effectively reduce the accumulation of H_2O_2 and MDA under low temperature stress,improve the efficiency of AsA-GSH cycle and reduce the damage of low temperature to sweet cherry stigma and ovary.The results of this study provide a theoretical basis for clarifying the mechanism of H_2S to alleviate the low temperature injury of sweet cherry organ and the prevention of low temperature injury during the flowering period.