干旱胁迫下外源亚精胺、甜菜碱对菘蓝种子萌发和幼苗生理特性的影响

以菘蓝为试验材料,在10%聚乙二醇（PEG-6000）干旱胁迫处理下,研究了外源亚精胺（Spd）和甜菜碱（GB）对菘蓝种子萌发和幼苗渗透调节物质、活性氧生成及膜质过氧化的影响。结果表明,外源Spd（≤75mg/L）和GB（≤30mmol/L）处理可显著促进干旱胁迫下菘蓝种子的萌发;25~100mg/L的Spd和10~40mmol/L的GB处理均可提高幼苗叶绿素含量,降低脯氨酸含量、丙二醛积累和细胞膜透性,可有效缓解干旱胁迫伤害,且幼苗中超氧化物歧化酶、过氧化氢酶和过氧化物酶活性均呈先上升后下降的趋势,并在Spd 75mg/L和GB 30mmol/L时达到最大值。由此可见,75mg/L的Spd或30mmol/L的GB能有效缓解干旱胁迫对菘蓝种子萌发及幼苗生长产生的伤害,提高种子及幼苗的抗旱能力。

Effects of Exogenous Spermidine and Glycine Betaine on Seed Germination and Physiological Characteristics of Isatis indigotica Fort. Seedlings under Drought Stress

The effects of exogenous spermidine(Spd)and glycine betaine(GB)on osmotic regulators,reactive oxygen species and membrane peroxidation in seed germination and seedling of Isatis indigotica Fort.were studied under 10%PEG drought stress.The results showed that the exogenous Spd(≤75mg/L)and GB(≤30mmol/L)could significantly promote the seed germination of Isatis indigotica Fort.under drought stress.Spd(25-100mg/L)and GB(10-40mmol/L)treatments could improve chlorophyll content,reduce proline content,malondialdehyde accumulation and membrane permeability of seedlings,and effectively alleviate the damage of drought stress.With the addition of exogenous Spd(25-100mg/L)and GB(10-40mmol/L),SOD,CAT and POD activities in seedlings all showed a trend of"increasing first and then decreasing",and reached the maximum value under the T3 treatments(Spd 75mg/L and GB 30mmol/L).Therefore,Spd(75mg/L)and GB(30mmol/L)can effectively reduce the damage of drought stress on seed germination and seedling growth of Isatis indigotica Fort.,and improve the drought resistance of seeds and seedlings.