AgNO_3对草莓试管苗生长及抗氧化酶活性的影响

Effects of different AgNO_3 levels on the growth and activities of antioxi-dant enzymes in strawberry in vitro

为了探讨重金属离子对果树的毒性机制,以草莓(Fragaria ananassa Duch．)主栽品种丰香(Toyonoka)和章姬(Akihime)组培苗为外植体,研究了不同浓度AgNO3对草莓生长及抗氧化酶活性的影响。结果表明,1／2MS培养基中有AgNO3存在时,2个草莓品种的根干质量和根长明显增加,根系活力随着AgNO3浓度的增加而增加,1．0 mg／L时达最大值,而根系含水量则随着AgNO3浓度的增加逐渐降低。AgNO3浓度为0．5-1．0 mg／L时,植株株高和干质量逐渐下降,而叶绿素、可溶性蛋白的含量和抗氧化酶的活性则逐渐增加。叶片中MDA的含量、O2-的产生速率、脯氨酸的含量和IAA氧化酶的活性随着AgNO3浓度的增加而增加,而IAA的含量则逐渐降低。

Effects of different AgNO3 levels on the growth and the activities of antioxidant enzymes in two cuhivars of Fragaria ananassa Duch. cv. Toyonoka and Akihime were studied. Half-strength MS medium, containing appropriate concentration of AgNO3 （≤ 1.0 mg/L） could significantly increase root length, dry weight and activity. Shoot height and dry weights of plantlets were reduced in the presence of 0.5-1.0 mg/L AgNO3 while chlorophyll contents, soluble protein contents, superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） activities in leaves were increased and reached the maximum at 1.0 mg/L AgNO3. Superoxide free radicals （O2^-.） production rate, malondialdehyde （MDA） content, proline content and IAA-oxidase activity in leaves were increased while root water content and indole-3-actic acid （IAA） content was decreased with the addition of 0.5-4.0 mg/L AgNO3.