镉(Cd)胁迫对5种类型黄瓜幼苗生长、抗氧化酶活性及镉积累量的影响

Effects of Cd^(2+) Stress on Growth,Antioxidant Enzyme Activity and Cadmium Enrichment of Cucumber Seedings

采用营养液培养方法,以目前我国代表性较强的5种黄瓜(Cucumis sativus L.)类型(华北型Ⅰ、华北型Ⅱ、华南型、欧美温室型、欧美加工型)为对象,研究不同镉(Cd)浓度(0、5、10、50、100、300μmol/L)胁迫对黄瓜幼苗生长、抗氧化酶活性以及镉累积的影响。结果表明,黄瓜株高随着镉浓度升高而降低,在0~300μmol/L镉浓度范围内,华南型均高于等镉浓度时的其它4种类型;根体积在0~50μmol/L镉浓度范围内呈现逐渐增大的趋势,在100、300μmol/L处理时根系生长受到明显抑制;各类型黄瓜的SOD、POD、CAT活性随着镉浓度升高整体呈现先增后降的趋势;镉浓度在50μmol/L以下时,地上部镉富集量整体大于根部,而镉浓度在100、300μmol/L时则呈相反趋势;高镉浓度(300μmol/L)胁迫下,欧美加工型和华北Ⅰ型地上部镉累积量显著低于其它处理,呈现出较好的镉低累积能力。本研究可为黄瓜镉低富集品种的筛选提供数据支持。

Using 5 cucumber varieties（ North China Ⅰ,North China Ⅱ,Southern China,Europe and the United States in greenhouse,Europe and the United States processing） as materials,the effects of different concentrations of cadmium（ 0,5,10,50,100,300 μmol/L） stress on growth,antioxidant enzyme activity and cadmium enrichment of cucumber seedings were studied under hydroponic condition. The results showed that the cucumber plant height decreased with the increase of cadmium concentration,and the Southern Chinawere all higher than the other four types in the same concentration of cadmium. The root volume showed a gradual increasing trend in the cadmium concentration range of 0 - 50 μmol/L,and the root growth was inhibited in the 100 μmol/L and 300 μmol/L cadmium concentration. The SOD,POD,CAT activity of cucumber seedings increased at first and then decreased with the increase of Cd concentration. The whole Cd enrichment of aboveground plant was higher than the root when the cadmium concentration was below 50 μmol/L,while it showed a reverse trend in 100,300 μmol/L. The Cd enrichment of aboveground part of Europe and the United States processing and North China Ⅰ were significantly lower than other treatments under the high cadmium concentration（ 300 μmol/L） condition and showed better low-Cd accumulation ability. The study provided data supports for screening out cucumber varieties with low concentration of cadmium.