不同口器昆虫取食对烟草信号分子及次生代谢物的影响

发布时间：2018-12-21 20:01

【摘要】：在大自然生存环境中,植物和昆虫之间的相互关系十分复杂多变,植食性昆虫取食会增强植物的防御进化过程,反之,植物的自我防御又增强了昆虫对植物的适应。本文中,以白肋烟和烤烟为模式植物,研究刺吸式口器和咀嚼式口器昆虫取食烟草时,发现不仅烟草体内的信号分子一氧化氮和茉莉酸的含量会发生显著变化,防御性物质也会有不同程度的改变。为测定不同口器昆虫取食烟草及不同种类的烟草受到相同昆虫胁迫时,对烟草信号分子和次生代谢物质的影响,本文以烤烟和白肋烟为试验对象,分析测定了咀嚼式口器(斜纹夜蛾,Spodoptera litura)和刺吸式口器(烟蚜,Myzuspersicae)取食后,烟草叶部在3天、6天、10天、15天内生物碱和蔗糖酯及叶部和根部在3小时、6小时、9小时、12小时内一氧化氮和茉莉酸的含量变化。试验表明,对烤烟而言,烟蚜取食后,烟株的防御系统被激活,叶部降烟碱、烟碱和总生物碱含量显著增加,第6天达到最高,较对照增加27.92%、89.80%和82.20%;斜纹夜蛾取食后生物碱亦呈逐渐上升后下降趋势,且在第6天含量达到最高,降烟碱、烟碱和总生物碱分别较对照增加34.31%、84.06%和79.15%。烟蚜和斜纹夜蛾取食烟株后,烟草体内的另一种防御性物质蔗糖酯也在不同时间内有相似的影响。烟叶中的蔗糖酯含量均在第10天达到最高,分别较对照增加60.14%和65.90%。而对照组SE含量变化不明显。类似地,对白肋烟而言,斜纹夜蛾取食后,降烟碱、烟碱和总生物碱含量分别较对照增加77.80%、89.83%和82.12%;斜纹夜蛾取食后,在第10天达到峰值,较对照增加133.33%。对烤烟而言,烟蚜和斜纹夜蛾取食后,信号分子一氧化氮和茉莉酸的含量在12小时内出现波动:在叶部和根部,处理组和对照组中NO含量均呈先增加后降低的趋势,9小时达到峰值;处理组中叶部与根部的JA含量较对照显著增加,在12小时内,叶部表现为先升后降,根部则呈持续上升态势。斜纹夜蛾取食白肋烟后,信号分子也有相似的变化趋势。试验研究也间接地表明,同处一个塑料大棚的对照组植株中生物碱、蔗糖酯含量也有一定程度的增加;植株不同部位信号分子含量亦有波动,推测昆虫的取食可能会激发邻近对照植株的防御反应。间接或直接地说明实践上可利用挥发性外源信号分子如茉莉酸甲酯(Methyl jasmonate,MeJA)等强化植株自身的防御反应,以减少化学农药的使用。
[Abstract]:In the natural living environment, the relationship between plant and insect is very complex and changeable. The phytophagous insect feeding will enhance the defensive evolution process of plant, on the contrary, the self-defense of plant will enhance the adaptation of insect to plant. In this paper, using Burley tobacco and flue-cured tobacco as model plants, it was found that the contents of nitric oxide and jasmonic acid, not only signaling molecules in tobacco, but also the contents of nitric oxide and jasmonic acid in tobacco, were significantly changed. Defensive substances can also change to varying degrees. In order to determine the effects of different mouthparts on tobacco signaling molecules and secondary metabolites under the same insect stress, flue-cured tobacco and Burley tobacco were studied. The masticatory mouthparts (, Spodoptera litura) and, Myzuspersicae) were used to determine the alkaloids and sucrose esters in tobacco leaves within 3 days, 6 days, 10 days, and 15 days after feeding by, Myzuspersicae), and the leaves and roots were at 3 hours, 6 hours and 15 days, respectively. The contents of nitric oxide and jasmonic acid changed within 9 hours and 12 hours. The results showed that, for flue-cured tobacco, the defense system of tobacco plant was activated, the contents of nicotine, nicotine and total alkaloids in leaves increased significantly, and reached the highest level on the 6th day, which increased 27.9289.80% and 82.20% compared with the control. After feeding, the alkaloids of Spodoptera litura increased gradually and then decreased, and reached the highest level on the 6th day, and the contents of nicotine, nicotine and total alkaloids increased 34.31% and 79.15%, respectively, compared with the control. Another defensive substance, sucrose ester, had a similar effect at different time after aphid and Spodoptera litura fed on tobacco plant. The content of sucrose esters in tobacco leaves reached the highest on the 10th day, which increased by 60.14% and 65.90 compared with the control, respectively. There was no significant change in SE content in the control group. Similarly, for Burley tobacco, the contents of nicotine, nicotine and total alkaloids of Spodoptera litura increased 77.8089.83% and 82.12%, respectively. After feeding, Spodoptera litura reached its peak on the 10th day, 133.33 more than the control. For flue-cured tobacco, the contents of signal molecule nitric oxide and jasmonic acid fluctuated within 12 hours after feeding by aphid and Spodoptera litura. The NO content in the leaves and roots of the treatment group and the control group increased first and then decreased. The peak value was reached at 9 hours. The content of JA in the middle leaf and root of the treatment group was significantly higher than that in the control group. Within 12 hours, the content of JA in the middle leaf and root increased first and then decreased, and the root showed a continuous rising trend. The signal molecules of Spodoptera litura showed a similar trend after feeding Burley tobacco. The experimental results also indirectly showed that the alkaloids and sucrose esters in the control plants in the same plastic greenhouse also increased to a certain extent. The signal molecular content fluctuated in different parts of the plant, which suggested that the insect feeding might stimulate the defense response of the adjacent control plants. It is suggested indirectly or directly that volatile exogenous signaling molecules such as methyl jasmonate (Methyl jasmonate,MeJA) can be used to enhance the defense response of plants in order to reduce the use of chemical pesticides.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S435.72

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