外源一氧化氮对铝胁迫下黑麦草幼苗生长和生理的影响

Effects of exogenous nitric oxide on the growth andphysiology of ryegrass seedlings under aluminum stress

摘要:

为探究外源一氧化氮对黑麦草铝毒害的缓解作用,以铝敏感型黑麦草品种Nagahahikari和铝耐受型黑麦草品种特高为试验材料,研究不同浓度(100和200 μmol/L)硝普钠(SNP)对20 mmol/L铝胁迫下两种黑麦草生长特性和生理指标的影响。结果表明:外源NO处理可提高黑麦草幼苗的OJIP荧光瞬态曲线,提高量子产率,量子效率,比能量通量,可溶糖含量,可溶性蛋白含量,显著提高叶绿素a含量,叶绿素总量,超氧化物歧化酶(SOD)活性,过氧化物酶(POD)活性和过氧化氢酶(CAT)活性(P＜0.05),显著降低丙二醛(MDA)含量和相对电导率并降低黑麦草对铝的富集量(P＜0.05)。和仅铝胁迫相比较,添加200 μmol/L SNP,Nagahahikari和特高的相对电导率分别下降34.85%和27.35%,SOD活性分别提高28.66%和37.18%,POD活性分别提高52.41%和50.30%,地上部Al3+富集量分别下降34.95%和29.33%,根系中Al3+富集量分别下降26.02%和17.37%,添加100 μmol/L SNP对两种黑麦草的生长和生理指标也有积极的影响,但效果弱于添加200μmol/L SNP。说明添加外源NO能够促进铝胁迫下黑麦草的生长和生物量的积累,且对铝敏感型品种Nagahahikari所受铝毒害的缓解效果优于铝耐受型“特高”。

Abstract:

The objective of this study was to investigate the alleviative effects of exogenous nitric oxide(NO)on aluminum(Al)toxicity in ryegrass seedlings.Ryegrass cv.Te Gao,Al-tolerant and cv.Nagahahikari,Al-sensitive were grown in sand to investigate the effects of two different concentrations(100,200 μmol/L)of sodium nitroprusside(SNP)on the growth and physiological parameters of ryegrass under 20 mmol/L Al3+.The results showed that exogenous NO treatment increased chlorophyll fluorescence parameters,soluble sugar content,soluble protein content,chlorophyll a content,total chlorophyll content,SOD activity,POD activity and CAT activity(p＜0.05),while significantly reduced MDA content and electrical conductivity,and the accumulation of Al3+ in ryegrass(p＜0.05).Compared with Al stress only,the application of 200 μmol/L SNP under Al stress reduced the relative electricity conductivity by 34.85% and 27.35%,increased SOD activity by 28.66% and 37.18% and SOD activity by 52.41% and 50.30%,reduced Al3+ enrichment in shoots by 34.95% and 29.33% and in roots by 26.02% and 17.37% in Nagahahikari and Te Gao,respectively.The results indicated that the alleviative effects of NO treatment on the growth of ryegrass exposed to Al stress was more significant in the Al-sensitive ryegrass cv.Nagahahikari than that of Al-tolerant cv.Te Gao.