钾水平对小麦酚类物质、木质素代谢和接种蚜虫群体动态的影响

Study of Effects of Potassium Levels on Phenolic and Lignin Metabolism of Wheat and Dynamic of Aphid Population

揭示钾素水平对小麦后期蚜虫抗性的影响效果及其机理,为指导钾肥合理施用,降低小麦蚜虫危害提供依据。利用设置K0(0)、K1(0.1K2Omg/kg土)、K2(0.15K2Omg/kg土)3个钾处理的盆栽试验并结合室内分析,研究了供钾水平对小麦后期酚类物质、木质素含量及其代谢相关酶活性的影响,比较了处理间接种蚜虫种群变化动态的差异。结果表明:接虫后14～28天,单株小麦蚜虫数量不同施钾处理间出现明显的差异,其中以K0蚜虫群体最高,其次是K2,K1最低。群体高峰期出现时间K2、K0较K1提前2～3天。3个处理相比,K1植株总酚、酚酸、木质素含量及其代谢相关酶(PAL、TAL、POD、PPO)活性最高,其次是K2,K0最低。相关分析表明,植株总酚、酚酸、木质素含量及其代谢相关酶活性与植株钾素含量相关性不显著,但与植株干物质积累量及籽粒产量相关性显著。适量供钾可增加植株对钾素的吸收,促进了植株生长和总酚、酚酸、木质素的合成及代谢相关酶的活性,从而可增加小麦对蚜虫的抗性;而供钾不足或过量,或降低了植株对钾素的吸收,或使植株对钾素产生奢侈吸收,均不利于植株干物质积累和酚类物质、木质素的合成,从而降低了小麦对蚜虫的抗性。

This study was to elucidate the effect of potassium levels on plant aphid resistance in wheat at late growing stage and the relative physiological mechanism.A pot experiment with three K levels treatments of K0（0 mgK2O/kg）,K1（0.1 mgK2O/kg） and K2（0.15mg K2O/kg）,combined with laboratory plant analysis was conducted to study the effects of K levels on the content of plant phenol,lignin and enzyme activity which play roles in the phenolics and lignin metabolism in wheat at late growing stage and investigate the difference of aphid population among the treatments.The aphid population per plant showed significant variance among the three treatments during 14 d to 28 d after inoculation with K0 having the largest aphid population,K2 the medium,K1 the minimum.The aphid population peak time was postponed about 2 to 3 days for K0 and K2 compared with K1.The content of total phenol,phenolic acids,lignin and the enzyme activity of phenylalanine ammonia lyase（PAL）,tyrosine ammonia lyase（TAL）,peroxidase（POD） polyphenol oxidase（PPO） were in the order of K1〉 K2〉K0.There were significant correlation between the content of total phenol,phenolic acids,lignin,enzyme activity of phenylalanine ammonia lyase（PAL）,tyrosine ammonia lyase（TAL）,peroxidase（POD）,polyphenol oxidase（PPO） and the dry weight or grain weight,but not between the content of total phenol,phenolic acids,lignin,enzyme activity of phenylalanine ammonia lyase（PAL）,tyrosine ammonia lyase（TAL）,peroxidase（POD）,polyphenol oxidase（PPO） and plant potassium content.Supplying potassium with sufficient quantum can increase wheat aphid resistance at late growing stage by improving phenolics or lignin metabolism combined with enhanced plant dry weight,supplying potassium with over or deficient quantum may both decrease aphid resistance by depressing phenolics or lignin metabolism combined with reduced plant dry weight.