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目的通过对决明子萌发及幼苗生理特性的研究,寻找提高决明子及幼苗在盐胁迫条件下抗性能力的途径。方法测定盐胁迫下决明子在经过不同质量浓度的外源性5-氨基乙酰丙酸(ALA)处理后,种子的发芽势、发芽率、发芽指数和活力指数,并对决明幼苗叶片叶绿素量、叶绿素荧光参数、原生质膜透性、叶片丙二醛(MDA)量、可溶性糖量、可溶性蛋白量及脯氨酸量及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性进行测定。结果 100 mmol/L盐胁迫下的决明子萌发受到显著抑制,但是经过不同质量浓度的ALA处理后,萌发指标均有升高。结果表明,外源性ALA处理显著提高了决明子发芽势、发芽率、发芽指数和活力指数,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),降低了原生质膜透性、叶片的MDA量及非光化学淬灭系数(NPQ),提高了盐胁迫下幼苗叶片可溶性糖、可溶性蛋白和脯氨酸量,显著提高了叶片SOD、POD、CAT活性。结论外源性ALA通过提高决明子的萌发指数,提高幼苗光合效率、渗透调节物质量及抗氧化酶活性,有效地减缓盐胁迫对决明子及幼苗产生的伤害,提高种子及幼苗的抗盐能力。
Aim To study the germination and physiological characteristics of cassia seed to find ways to improve the resistance of cassia seedlings and seedlings to salt stress. Methods The seed germination potential, germination rate, germination index and vigor index of Cassia seedlings under salt stress were determined by different concentrations of exogenous 5-aminolevulinic acid (ALA). The contents of chlorophyll, (Superscript +), peroxidase (POD) and hydrogen peroxide (POD), the content of soluble sugar, Enzyme (CAT) activity was measured. Results The germination of cassia seed was significantly inhibited under salt stress of 100 mmol / L, but the germination index increased after treated with different concentrations of ALA. The results showed that exogenous ALA treatment significantly increased the germination potential, germination rate, germination index and vigor index of cassia seed, increased chlorophyll a, chlorophyll b and total chlorophyll, significantly increased the maximum photochemical efficiency (Fv / Fm), PSII (Fv ’/ Fm’), PSII actual photochemical efficiency (ΦPSII) and photochemical quenching coefficient (qP), decreased plasma membrane permeability, MDA content in leaves and non-photochemical quenching coefficient (NPQ) The contents of soluble sugar, soluble protein and proline in leaves of seedlings under salt stress significantly increased the activity of SOD, POD and CAT. Conclusions Exogenous ALA can effectively increase the photosynthetic efficiency, osmotic adjustment and antioxidant enzyme activities of seedlings by increasing the germination index of cassia seed, and effectively slow down the damage caused by salt stress to cassia seedlings and seedlings and improve the salt tolerance of seeds and seedlings.