外源CO供体高铁血红蛋白对盐胁迫下决明种子萌发及幼苗生理特性的影响

Effect of exogenous carbon monoxide donor hematin on seed germination and physiological characteristics of Cassia obtusifolia seedlings under NaCl stress

目的:通过对决明种子萌发及幼苗生理特性的研究,寻找提高决明种子及幼苗在盐胁迫条件下抗性能力的途径。方法:测定在外源CO供体高铁血红蛋白(hematin)处理后,NaCl胁迫下决明种子的发芽势(Gv)、发芽率(Gr)、发芽指数(Gi)和活力指数(Vi),并对决明幼苗叶片相对含水量、叶绿素含量、叶绿素荧光参数、可溶性糖、可溶性蛋白、脯氨酸及丙二醛(MDA)含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性进行测定。结果:120 mmol.L-1的NaCl胁迫下的决明种子萌发受到显著抑制,但是经过不同浓度的hematin处理后,萌发指标均有升高。试验结果表明,外源hematin处理显著提高了决明种子发芽势、发芽率、萌发指数和活力指数,提高了叶片叶绿素a、叶绿素b和总叶绿素的含量,显著提高了最大光化学效率(Fv/Fm),PSⅡ有效光化学效率(Fv'/Fm'),PSⅡ实际光化学效率(ΦPSⅡ),光化学淬灭系数(qP),降低了非光化学淬灭系数(NPQ)及叶片丙二醛(MDA)含量,提高了盐胁迫下决明幼苗叶片相对含水量、可溶性糖、可溶性蛋白和脯氨酸含量,不同程度的提高了叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,而CO清除剂血红蛋白(Hb)则逆转了CO供体对盐胁迫下决明幼苗氧化损伤的缓解效应。结论:外源CO供体高铁血红蛋白(hematin)通过提高决明种子的萌发指数,提高幼苗光合效率、渗透调节物质含量及抗氧化酶活性,有效地减缓NaCl胁迫对决明种子及幼苗产生的伤害,提高种子及幼苗的抗盐能力。

Objective:In order to get the method to improve the salt resistance of seeds and seedlings for Cassia obtusifolia under NaCl stress,seed germination and physiological characteristics of C.obtusifolia seedlings were studied.Method:Several physiological indexes of C.obtusifolia seeds treated with exogenous carbon monoxide donor hematin under NaCl stress like the germination vigor,germination rate,germination index and vigor index were measured.And other indexes like the relative water content,the contents of photosynthetic pigment,chlorophyll fluorescence parameters,the contents of soluble surge,protein and proline,malondialdehyde(MDA),the activities of superoxide(SOD),peroxidase(POD) and catalase(CAT) were also measured.Result:The germination indexes of C.obtusifolia seeds under NaCl stress had been inhibited obviously.But after the treatment of hematin,every germination indexes were all increased.The result showed that the treatment of exogenous CO donor hematin obviously improved the germination vigor,germination rate,germination index and vigor index,increased the content of chlorophyll a,chlorophyll b,total chlorophyll,improved the photochemical efficiency of photosystem II(Fv/Fm),photochemical efficiency(Fv'/Fm'),PSⅡactual photochemical efficiency(ΦPSⅡ),photochemical quench coefficient(qP),decreased non-photochemical quenching coefficient(NPQ) and the content of malondialdehyde(MDA),increased the relative water content of leaves and the content of soluble surge,protein and proline.Meanwhile,the results also indicated that CO improved the activities of superoxide(SOD),peroxidase(POD) and catalase(CAT).The effects of CO could be reversed when CO scavenger Hb is added.Conclusion:Exogenous CO donor hematin with appropriate concentration could significantly alleviate the damages to the seeds and seedlings of C.obtusifolia under NaCl stress and promote the salt resistance of the seeds and seedlings through improving the germination indexes,the photochemical efficiency and the antioxidase activities of the seedlings.