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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: To find a way to improve the resistance of Cassia thompson seed and seedling to salt stress by studying the germination and seedling physiological characteristics of Cassia thompson seed. Methods: The germination potential (Gv), germination rate (Gr), germination index (Gi) and viability index (Vi) of Cassia obtusifolia seeds treated with exogenous CO donor hematin were measured. The relative water content, chlorophyll content, chlorophyll fluorescence parameters, soluble sugar, soluble protein, proline and malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD) Hydrogenase (CAT) activity was measured. Results: The seed germination of Cassia obtusifolia under 120 mmol.L-1 NaCl stress was significantly inhibited, but after different concentrations of hematin treatment, the germination index increased. The results showed that the exogenous hematin treatment significantly increased the germination potential, germination rate, germination index and vigor index of Cassia obovata, increased the contents of chlorophyll a, chlorophyll b and total chlorophyll, and significantly increased the maximum photochemical efficiency (Fv / Fm ), PSⅡeffective photochemical efficiency (Fv ’/ Fm’), PSⅡeffective photochemical efficiency (ΦPSⅡ) and photochemical quenching coefficient (qP), and decreased NPQ and MDA content. Increased the relative water content, soluble sugar, soluble protein and proline content of leaves of Cassia obmentivora seedlings under salt stress, increased the contents of superoxide dismutase (SOD), peroxidase (POD) and hydrogen peroxide (CAT) activity, while the CO scavenger hemoglobin (Hb) reversed the effect of CO donor on oxidative damage induced by salt stress. CONCLUSION: Hematin, an exogenous CO donor, can effectively slow down the damage caused by NaCl stress to seeds and seedlings of Cassia obtusifolia by increasing the germination index of Cassia obtusifolia, improving the photosynthetic efficiency, osmotic adjustment substance content and antioxidant enzyme activity, Improve seed and seedling salt resistance.