截形叶螨取食对马铃薯酶活性的影响

Effect of Tetranychus truncatus Feeding on Enzyme Activities of Solanum tuberosum

为明确截形叶螨(Tetranychus truncatus)取食刺激对不同耐旱型马铃薯(Solanum tuberosum)品种酶活性的影响,选择2个马铃薯品种(‘荷兰15号’,早熟,干旱敏感型品种;‘陇薯10号’,晚熟,耐旱型品种),在人工接螨后,测定7天内马铃薯叶片5种防御酶(CAT、POD、PPO、PAL、LOX)活性的变化。CAT、POD、PPO、PAL、LOX等5种酶活性在受螨害刺激后均表现出不同程度的升高,在时序上都表现为先升高后下降的趋势,且在3天后显著高于CK(未接螨的健康植株),5种酶均参与了植物机体对害螨的防御反应,以促进受害植株体内自由氧的消减,通过木质素、花青素、生物碱等苯丙素类化合物、氢过氧化物等含量的提高来增强机体防御能力;在螨害7天后,5种酶活性都显著下降,且显著低于CK,说明叶螨在长时间危害后可能导致植株机体紊乱,植株不能很好地持续维持高效的对螨害的防御响应。2个马铃薯品种在叶螨为害后同一时间内,从CAT、PPO和PAL活性变化角度分析,干旱敏感型马铃薯品种表现出较高的抗螨性;被叶螨取食为害后耐旱型马铃薯品种POD活性较高,但干旱敏感型马铃薯品种POD活性增长幅度更大;2个品种在LOX活性上无显著差异。总体分析可得,干旱敏感型马铃薯比耐旱型品种有更高的抗螨性。研究结果可为马铃薯叶螨的科学防治和品种选育提供理论依据。

In order to clarify the effect of feeding stimulation of Tetranychus truncatus on enzyme activities of different drought-tolerant potato(Solanum tuberosum) varieties, two potato varieties(‘Netherlands No.15’,early maturing, drought-sensitive;‘Longshu 10’, late-maturing, drought-tolerant) were inoculated with mites,and the activities of 5 defense enzymes(CAT, POD, PPO, PAL and LOX) in potato leaves were determined within 7 days. The results showed that the activities of CAT, POD, PPO, PAL and LOX increased to different degrees after the stimulation of mites, and showed a trend of first increase and then decrease in time sequence,and were significantly higher than those of CK(healthy plant without mites) after 3 days. All the 5 enzymes were involved in the defense response of plants to mites, so as to promote the reduction of free oxygen in the injured plants, and increase the contents of phenylpropanoids, such as lignin, anthocyanin and alkaloids, and hydroperoxides to enhance the defense ability of plants. 7 days after mite damage, the activities of the 5enzymes significantly decreased, and were significantly lower than those of CK, indicating that leaf mites might lead to plant disorder after long-term damage, so the plants could not well maintain efficient defense responses to mite damage. The activities of CAT, PPO and PAL of the two potato varieties were analyzed at the same time after leaf mite damage, and the drought-sensitive potato variety showed high resistance to mites. Although the POD activity of drought-tolerant potato variety was higher after being fed by spider mites, the POD activity of drought-sensitive potato variety increased more. There was no significant difference of LOX activity between the two varieties. Overall analysis showed that drought-sensitive potato had higher resistance to mites than drought-tolerant varieties. The results can provide a theoretical basis for the scientific control of leaf mites and variety breeding of potato.