朱砂叶螨不同侵染时间对木薯生理指标的影响

【目的】探讨不同木薯品种在朱砂叶螨刺吸胁迫下的生理生化指标变化,为木薯的抗螨品种选育提供理论依据。【方法】田间调查华南8号、南植199和华南205等3个木薯品种朱砂叶螨的种群数量;采用盆栽法比较接螨叶片(处理)与健康叶片(对照)的叶绿素、可溶性糖、可溶性蛋白、脯氨酸和丙二醛(MDA)含量及超氧化物岐化酶(SOD)和过氧化物酶(POD)活性等生理生化指标差异。【结果】不同木薯品种的朱砂叶螨种群数量在调查期内同时出现一个高峰(10月30日左右),其中华南205朱砂叶螨高峰期种群数量最多(105.6±6.9头/叶),其次为南植199(53.2±8.6头/叶),华南8号种群数量最少(38.7±3.8头/叶)。朱砂叶螨为害后,3个木薯品种叶片的叶绿素含量与同期对照相比均降低;叶片可溶性糖、可溶性蛋白、游离脯氨酸和MDA含量与同期对照的比值整体上呈先升高后降低的变化趋势,SOD和POD活性整体上有升高趋势。其中抗螨品种华南8号的可溶性糖、可溶性蛋白和游离脯氨酸含量及SOD和POD活性与同期对照的比值上升幅度较大,感螨品种华南205的上述生理指标较同期对照升高幅度较小。【结论】在朱砂叶螨刺吸胁迫下,不同木薯品种的叶片可溶性糖、可溶性蛋白和游离脯氨酸含量及SOD和POD活性存在显著差异,初步推测这几项生理指标变化可作为鉴定木薯品种抗螨性强弱的依据。

Effects of Tetranychus cinnabarinus infection time on physiological parameters of cassava

Objective]In order to provide theoretical basis for breeding mite-resistant cassava varieties,changes of physiological parameters of different cassava varieties were investigated after being infested by Tetranychus cinnabarinus.Method]The population quantity of T. cinnabarinus were explored on cassava varieties SC8,Nanzhi 199,and SC205 through field investigation. The physiological and biochemical parameters including contents of chlorophyll,soluble su-gar,soluble protein,free proline,malonaldehyde(MDA),superoxide dismutase(SOD)activity and peroxidase(POD)ac-tivities of leaves infested by T. cinnabarinus(treatment)and healthy leaves(control)were compared with pot method.Result]The population quantity of T. cinnabarinus on different cassava varieties appeared a peak during the period of in-vestigation(near October 30). Largest population quantity at the peak was showed on SC205(105.6±6.9 T. cinnabarinus/leaf),followed by Nanzhi 199(53.2±8.6 T. cinnabarinus/leaf),the smallest quantity was on SC8(38.7±3.8 T. cinnabari-nus/leaf). Compared with control group at the same period,the chlorophyll content of all cassava varieties decreased after being damaged by T. cinnabarinus;soluble sugar,soluble protein,free proline and MDA content increased firstly and then decreased generally,activities of SOD and POD showed a rising tendency overall. Soluble sugar,soluble protein,free pro-line content,and activities of SOD and POD of mite-resistant variety SC8 had larger increase range than that in the con-trol. However mite-susceptible variety SC205 had smaller increase range in terms of the above parameters.Conclusion]During feeding press of T. cinnabarinus,different cassava varieties present significant differences in soluble sugar con-tent,soluble protein content,free proline content,activities of SOD and POD. It is referred that the variation of these pa-rameters can be used to identify mite resistance of cassava varieties.