PEG预处理对文冠果种子萌发和幼苗生长的影响

Effect of PEG pretreatment on seed germination and seedling growth of Xanthoceras sorbifolium

PEG是高分子渗透调节物质,可通过调节植物细胞内的水势变化影响种子萌发。本研究以文冠果种子为试验材料,利用不同质量浓度(15%、20%、25%、30%、35%)聚乙二醇(PEG)对文冠果种子预处理,研究不同浓度PEG种子预处理对文冠果种子萌发及幼苗生长的影响。结果表明:(1)PEG浓度为15%~25%时,可以提高种子的发芽率、发芽势及发芽指数,当浓度超过25%,发芽受到抑制。(2)幼苗的苗高和地径生长量随PEG浓度升高呈现先增加后降低的趋势,在20%PEG预处理时达到最高值。(3)幼苗叶片可溶性糖含量、脯氨酸含量、SOD和POD活性均随PEG浓度升高而增加;可溶性蛋白、CAT活性、叶绿素呈先增加后降低的趋势,在25%PEG预处理时达到峰值。(4)随PEG浓度升高,相对电导率和丙二醛(MDA)呈现先降低后升高趋势,2项指标分别在20%、25%PEG浓度时达到最低值。综合研究表明:低浓度PEG预处理(15%~25%)可促进文冠果种子萌发和幼苗生长,而高浓度PEG预处理(>25%)对其产生抑制作用。

The PEG was a high molecular osmotic regulator which could affect seed germination by regulating water potential in plant cells.In order to explore the regulation of polyethylene glycol(PEG)on drought-resistance of Xanthoceras sorbifolium,effects of different concentrations(15%、20%、25%、30%、35%)of PEG pretreatment on its seed germination and seedling growth were studied.The results showed that:(1)When PEG concentration was 15%25%,the germination rate,germination potential and germination index of seeds were increased,but the germination was inhibited when PEG concentration was over 25%;(2)Seedling height and ground diameter of seedlings increased firstly and then decreased with the increase of PEG concentration,and reached the highest value at 20%PEG pretreatment.(3)Contents of soluble sugar,proline and the activities of SOD,POD in seedling leaf increased with the increase of PEG concentration,while soluble protein,CAT activity and chlorophyll increased first and then decreased,and reached the peak value at 25%PEG pretreatment.(4)With the increase of PEG concentration,the relative conductivity and malondialdehyde(MDA)first decreased and then increased,reaching the lowest values at 20%and 25%PEG concentration respectively.In conclusion,low concentration PEG pretreatment(15%25%)could promote seed germination and seedling growth,while high concentration PEG pretreatment(>25%)can inhibits it.