Abstract:

【Objective】 We study on the changes of nutrients, metabolites and protective enzyme contents of cotton leaves in different density and different damage time byBemisia tabacistress to cotton plant lets to reveal the interaction between whitefly and cotton.【Method】 UsingB. tabaci, in the artificial climate room, used cotton (NJ-135) to breeding and experiments. By setting up treatment groups with different density :0 (control), 50 and 500 head/plant, covered with 140 mesh nylon mesh. After putting different density ofB. tabaci that had been fed on 24, 48 and 72h to determine the pro di aldehyde, pro line, catal ase, soluble protein content, soluble sugar and chlorophyll in the cotton leaves.【Results】 In the groups of 50 and 500 head/plant treatment, there was a positive correlation between changes in content of total protein, proline and catalase contents in cotton leaves and the duration of feeding byB. tabaci (3.23, 4.87 and 5.55 μg/mL, 3.84, 5.38 and 5.92 μg/mL; 0.85, 0.92 and 0.99 μg/g, 0.89, 0.98 and 1.21 μg/g; 9.81, 10.98 and 18.45 U/mg prot; 12.42, 15.29 and 19.16 U/mg prot). Soluble sugar content in leaves gradually decreases with increasing feeding time (16.77, 15.83 and 15.64 mg/g; 18.10, 15.75 and 7.84 mg/g). The content levels of malondialdehyde in leaves gradually decreased and then increased with feeding stress (3.76, 3.26 and 4.44 nmol/mg prot; 4.45, 3.94 and 5.15 nmol/mg prot). The dynamics of chlorophyll content changes between low and high density treatments was different, 50 heads/plant, showing a decrease followed by an increase (1.27, 0.90 and 1.92 mg/g), and 500 heads/plant as a gradual increase (0.50, 0.86 and 1.98 mg/g).【Conclusion】 This suggests that the activities of the defense related enzymes, nutrients, and metabolites were influenced by damage fromB. tabaci. The stress response of cotton leaves ofB. tabaci was led to the contents of related nutrients, products and defense enzymes will change. The high density ofB. tabaci was enhanced with this response, as well as the response of the time increases.

Key words: Bemisia tabaci; cotton seedling stage; pest stress; defense response

摘要：

【目的】研究不同密度与不同为害时间下,棉花植株对烟粉虱持续取食胁迫所产生防御应答响应,分析叶片中防御酶活性,营养物质和代谢产物含量的变化,分析烟粉虱与棉花的互作关系。【方法】在人工气候室内,叶片真叶生长至5叶的棉花植株(NJ-135)上,分别接入0头(对照)、50和500头烟粉虱,单株罩140目尼龙网,在烟粉虱持续取食24、48和72 h后,分别采集棉花叶片,测定总蛋白、可溶性糖、脯氨酸、丙二醛、过氧化氢酶和叶绿素的含量。【结果】50和500头/株处理组,烟粉虱持续取食24、48和72 h,叶片中总蛋白、脯氨酸、过氧化氢酶含量均与取食时间的增长呈正相关,随取食时间和密度的加大而增高(3.23, 4.87和5.55 μg/mL, 3.84, 5.38和5.92 μg/mL; 0.85, 0.92和0.99 μg/g, 0.89, 0.98和1.21 μg/g; 9.81, 10.98和18.45 U/mg prot; 12.42, 15.29和19.16 U/mg prot),叶片中可溶性糖含量随取食时间延长逐渐下降(16.77, 15.83和15.64 mg/g; 18.10, 15.75和7.84mg/g),丙二醛含量随烟粉虱持续取食时间延长先下降后升高(3.76, 3.26和4.44 nmol/mg prot; 4.45, 3.94和5.15 nmol/mg prot),叶绿素含量变化低密度与高密度处理含量动态变化不同,50头/株为先下降后上升(1.27, 0.90和1.92 mg/g),500头/株为逐渐上升(0.50, 0.86和1.98 mg/g)。【结论】 棉花叶片会对烟粉虱取食胁迫产生相应的防御应答,与棉花生理生化性质改变有关。密度与烟粉虱持续取食时间,均是诱导叶片内总蛋白、脯氨酸、丙二醛、过氧化氢酶、可溶性糖和叶绿素含量变化的因素。高密度的烟粉虱会增强这种应答的程度,随着为害时间的延长应答程度也随之增强。

关键词: 烟粉虱, 棉花苗期, 虫害胁迫, 防御应答