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为探寻缓解决明种子及幼苗干旱胁迫的方法,该文研究了在15%聚乙二醇(PEG-6000)模拟干旱胁迫下,施加不同体积分数的外源Spd对决明种子发芽率(Gr)、发芽指数(Gi)及活力指数(Vi)的影响,以及Spd处理对决明幼苗叶片的总叶绿素、超氧阴离子(O2-.)、丙二醛(MDA)、可溶性蛋白质、游离脯氨酸质量分数以及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性等生理指标的影响.结果表明:①在15%PEG-6000胁迫下,决明种子萌发受到显著抑制,经过不同体积分数的Spd处理后各项萌发指标均有显著提高,0.50mmol/L的Spd处理各项指标值增幅最大,种子发芽率(84.67)、发芽指数(95.10)和活力指数(7.30)与干旱对照相比分别提高了1.84,1.19和1.96倍.②不同体积分数Spd处理决明幼苗叶片后,与干旱对照的值相比,总叶绿素质量分数、SOD及POD活性显著升高,而可溶性蛋白、游离脯氨酸、O2-.、MDA质量分数及CAT活性则有不同程度的降低,且以0.50mmol/L Spd处理后的效果最为显著.研究表明适宜体积分数(0.50mmol/L)的Spd能显著提高干旱胁迫下决明种子的萌发能力,通过调节保护酶活性来有效减缓干旱胁迫对决明幼苗的伤害,缓解渗透调节物质的过度积累,提高决明种子及幼苗的耐旱能力.
In order to explore the method of alleviating the drought stress of seedling and seedling of Cassia obtusifolia, the germination rate (Gr) of Cassia seed in different volume fraction under the simulated drought stress of PEG-6000 was studied. , Germination index (Gi) and vigor index (Vi), and the effect of Spd on total chlorophyll, superoxide anion (O2-), malondialdehyde (MDA), soluble protein, free proline And the physiological indexes such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity were analyzed.The results showed that: ① Under the 15% PEG-6000 stress, (P <0.05). Spd treatment with different volume fraction of Spd significantly increased the germination index of all treatments, while Spd treatment of 0.50 mmol / L showed the highest increase in the index value, seed germination rate (84.67), germination index (95.10) and vigor index (7.30) increased by 1.84, 1.19 and 1.96 times respectively compared with the drought control.②Compared with the drought control, the total chlorophyll content, SOD and POD activity of Spd in different volume fraction were significantly increased , While soluble protein, free proline, O2 -, MDA content And CAT activity decreased to a certain extent, and the effect of Spd at 0.50mmol / L Spd was the most significant.The results showed that Spd with the proper volume fraction (0.50mmol / L) could significantly improve the germination ability of Cassia obovus under drought stress , Through the regulation of protective enzyme activity to effectively reduce the drought stress on the injury of Cassia seedlings to alleviate the excessive accumulation of osmotica and improve seedling and cassia seedling drought tolerance.