不同时期干旱胁迫对甘薯生长和抗氧化能力的影响

Effects of Drought Treatments at Different Growth Stages on Growth and the Activity of Antioxidant Enzymes in Sweetpotato

【目的】研究不同时期干旱胁迫导致甘薯减产的机理,为旱作地区甘薯生产提供理论依据和技术支撑。【方法】在人工控水条件下,以抗旱品种济薯21和不抗旱品种济紫薯1号为试验材料,每个品种设4个水分处理,分别为WW(全生育期正常灌水,对照)、DS1(发根分枝期干旱胁迫)、DS2(蔓薯并长期干旱胁迫)和DS3(快速膨大期干旱胁迫),研究不同时期干旱胁迫对甘薯生长和抗氧化能力的影响。【结果】干旱胁迫导致甘薯薯干产量显著下降,早期干旱胁迫薯干产量下降幅度最大,济薯21(抗旱品种)的DS1、DS2和DS3处理产量分别比对照减产32.24%、30.68%和13.76%,济紫薯1号(不抗旱品种)分别比对照减产44.02%、39.54%和17.87%。功能叶、纤维根和块根抗氧化酶活性均在干旱胁迫后升高,且干旱胁迫时间越早,抗氧化酶活性升高的幅度越大;各生育时期纤维根的酶活性均高于块根和功能叶,说明甘薯纤维根对干旱胁迫的敏感性最强。干旱胁迫可导致甘薯功能叶相对电导率升高,功能叶、纤维根和块根的MDA含量升高,且胁迫时间越早,升高的幅度越大。【结论】干旱胁迫时间越早,功能叶、纤维根和块根的抗氧化酶系统受破坏程度越大,从而抑制了甘薯叶片和根系的正常生长,限制了块根的形成和膨大,发根分枝期是甘薯块根产量对水分最敏感的时期。

【Objective】The aim of this study was to investigate the mechanism of yield reduction of sweetpotato(Ipomoea batatas(L.)Lam)caused by drought stress at different growth stages,so as to provide theoretical basis and technical support for production of sweetpotato in dryland areas.【Method】Field experiments were conducted under a rain exclusion shelter to investigate the effects of drought treatments at different growth stages on growth and the activity of antioxidant enzymes in sweetpotato.Two sweetpotato cultivars(JS 21,a drought-tolerant cultivar,and JZ 1,a drought-sensitive cultivar)were subjected to four drought stress treatments respectively,including WW(well watered during the whole growth period,constructed as a control),DS1(drought stress during the establishment stage),DS2(drought stress during the intermediate stage),and DS3(drought stress during the final stage).【Result】Drought stress resulted in significant decrease of dry weight in sweetpotato,and which declined most under the earliest drought stress.Compared with the control,the dry weight of storage roots of DS1,DS2 and DS3 in drought-tolerant cultivar(JS 21)were 32.24%,30.68%and 13.76%,respectively,while 44.02%,39.54%and 17.87%in drought-sensitive cultivar(JZ 1),respectively.The activity of antioxidant enzymes of functional leaves,fibrous roots and storage roots increased after drought stress.Similarly,the earlier of the drought stress,the greater influence on the activity of antioxidant enzymes was observed in sweetpotato.The enzyme activity in the fibrous roots in each stage was higher than that in the storage roots and the functional leaves.Our results indicated that the fibrous roots were the most sensitive to drought stress.Drought stress could lead to the increase of the relative electrical conductivity of functional leaves,and the MDA content in functional leaves,fibrous roots and storage roots of sweetpotato.The earlier the application of the drought stress in sweetpotato,the greater the increase of the MDA content was observed.【Conclusion】The earlier of the drought stress,the greater influence on the activity of antioxidant enzymes was observed in sweetpotato,and could not be renovated.Therefore,the normal growth of leaves and roots were inhibited,and the formation and bulking of storage roots were limited.Establishment stage of sweetpotato was the most sensitive to drought stress.