外源一氧化氮供体硝普钠对番茄幼苗盐胁迫伤害的缓解作用

Alleviating effect of exogenous nitric oxide donor sodium nitroprusside on tomato seedlings under salt stress

以硝普钠(SNP)为NO供体,番茄品种秦丰保冠幼苗为材料,研究50~800μmol·L-1 SNP对100 mmol·L^-1 NaCl下番茄幼苗生长、光合色素含量、气体交换参数、叶绿素荧光参数、膜脂过氧化及抗氧化酶活性的影响。结果显示:1)盐胁迫下,不同浓度SNP处理的番茄幼苗生长抑制均能得到有效缓解,同时叶片叶绿素含量、光合速率(P n)、气孔导度(G s)、最大荧光(F m)、PSⅡ最大光化学效率(F v/F m)、实际光化学效率(ΦPSⅡ)和光化学淬灭系数(qP)显著升高,初始荧光(F o)和非光化学淬灭系数(qN)显著降低,且SNP浓度为100μmol·L^-1时变幅均达最大;2)番茄幼苗在盐胁迫下叶片过氧化氢酶(CAT)活性变化不显著,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性显著升高,除400、800μmol·L^-1 SNP处理抑制POD活性升高外,各浓度SNP处理均可促进上述3种酶活性的升高,并使叶片丙二醛含量和电解质渗出率显著降低,其中以100μmol·L^-1 SNP处理时变化最显著。研究表明,外源NO供体SNP主要通过增强番茄幼苗叶片的光合能力来缓解盐胁迫对其造成的氧化伤害,进而提高了番茄植株的耐盐性。

In order to clarify the alleviating effects of exogenous nitric oxide(NO)on tomato seedlings under salt stress,using tomato variety Qinfengbaoguan as research object,and sodium nitroprusside(SNP)as donor of NO,the effects of different SNP concentration(50,100,200,400,800μmol·L^-1)on the growth,photosynthetic pigment contents,gas exchange and chlorophyll fluorescence parameters,membrane peroxidation and antioxidase activity under stress of 100 mmol·L^-1 NaCl were studied in this paper.The results showed that,under salt stress,the growth inhibition of tomato seedlings treated with different concentrations of SNP could be effectively alleviated.At the same time,chlorophyll content,photosynthetic rate(P n),stomatal conductance(G s),maximal fluorescence(F m),PSⅡmaximal photochemistry efficiency(F v/F m),practical photochemical efficiency(ΦPSⅡ)and photochemical fluorescence quenching coefficient(qP)of leaves increased significantly,while original fluorescence(F o)and non-photochemical quenching coefficient(qN)decreased significantly,and when the SNP concentration was 100μmol·L^-1,the variation range of each index reached the maximum.The activity of catalase(CAT)in tomato leaves was not significantly changed under salt stress,and the activity of superoxide dismutase(SOD)and peroxidase(POD)were significantly increased.Except that the activity of POD was inhibited by 400 and 800μmol·L^-1 SNP treatment,the SNP treatment at all concentrations could promote the increase of the above three enzyme activities,and significantly reduced the malondialdehyde content and electrolyte leakage rate in leaves,with the most significant change at 100μmol·L^-1.These results suggested that exogenous NO donor SNP alleviated the oxidative damage caused by salt stress by enhancing the photosynthetic ability of seedling leaves,and thus improved the salt tolerance of tomato plants.