老芒麦幼苗糖代谢对PEG模拟干旱胁迫的响应

Response of sugar metabolism to PEG-simulated drought stress in Elymus sibiricus Seedlings

摘要:

以青牧1号老芒麦(Elymus sibiricus cv.Qingmu No.1)为试验材料,采用不同浓度PEG模拟干旱胁迫,研究干旱对老芒麦幼苗糖代谢产物含量及酶活性的影响。结果表明:随着干旱胁迫的持续,老芒麦幼苗体内糖代谢相关产物含量及相关酶活性均发生改变,且高浓度干旱胁迫下变化幅度更明显。其中,低浓度处理下,蔗糖合成酶(Sucrose synthase,SS)活性较对照无显著变化,蔗糖磷酸合成酶(Sucrose phosphate synthase,SPS)活性于胁迫第8 d最大,增幅22.10%;酸性转化酶(Acid invertase,AI)和中性转化酶(Neutral invertase,NI)活性分别于第4 d和第12 d最强;可溶性糖含量变化呈升-降-升趋势;蔗糖含量无显著变化;果糖和葡萄糖含量分别于第8 d和第4 d最大,增幅分别为53.06%和46.33%;高浓度胁迫下, SS、SPS、AI和NI活性最强时期集中于胁迫8~12 d,且均显著高于各自对照和低浓度胁迫;可溶性糖含量于胁迫第20 d达最大;蔗糖、果糖和葡萄糖含量在胁迫中期(4~8 d)显著增加;综上所述,干旱胁迫下,老芒麦幼苗通过积累糖代谢产物含量和提高相关酶活性来适应干旱,从而提高老芒麦的抗旱能力。

Abstract:

This study investigated the effects of drought stress,simulated by different concentrations of PEG,on the content of sugar metabolism related products and the activity of sugar metabolism related enzymes in the seedlings of Elymus sibiricus cv.Qingmu No.1.The results showed that the content of sugar metabolism related products and the activity of related enzymes changed along the duration of drought,with more obvious effects under higher PEG concentration.Under low PEG concentration,the activity of sucrose synthetase (SS) had no significant difference compared with that of the control;the activity of sucrose phosphate synthetase (SPS) was highest after 8 days of stress,with a 22.10% increase;the activity of acid invertase (AI) and neutral invertase (NI) was highest at 4 d and 12 d,respectively.The change of soluble sugar content under low PEG treatment had a trend of a initial increase followed by a decrease later;the contents of fructose and glucose were highest on the 8th and 4th days (with an increase of 53.06% and 46.33%,respectively),while no significant change in sucrose content was observed.Under high PEG concentration,the highest activity of SS,SPS,AI and NI was observed between 8~12 days,which were significantly higher than those in the control and low PEG treatment.The content of soluble sugar under high PEG treatment reached the maximum at 20 days,while the content of sucrose,fructose and glucose increased significantly at the middle stage of stress (4~8 days).In summary,the seedlings of E.sibiricus could adapt to drought stress by increasing sugar metabolites and enhancing the activities of related enzymes.