【作者】 王志政；

【导师】 温俊宝； 宗世祥； 骆有庆；

【作者基本信息】 北京林业大学 ， 森林保护学， 2010， 硕士

【摘要】 沙棘木蠹蛾Holcocerus hippophaecolus属鳞翅目Lepidoptera木蠹蛾科Cossidae线角木蠹蛾属Holcocerus,是我国“三北”地区近10年来新出现的暴发性钻蛀性害虫,造成约16万hm2的沙棘林枯死,成为制约沙棘发展的主要因子。近年来,对沙棘木蠹蛾的生物生态学特性、天敌种类与自然控制效能、性信息素的开发应用、营林控制和化学防治等方面的研究报道较多,但对沙棘抗虫机制尚未涉及。探讨沙棘抗虫机制,有助于揭示沙棘木蠹蛾种群暴发的原因,从而为沙棘木蠹蛾的区域性控制提供科学依据。本研究主要采用野外生测和室内观察相结合的方法,探讨了沙棘木蠹蛾对不同树种的抗虫等级,并采用组织解剖学方法分析形态组织结构与抗性机制的关系。主要结果如下：(1)结合笼内人工接虫试验和野外自然感虫试验,以沙棘木蠹蛾对不同树种的着卵率和产卵率为目标,根据它们间的相关系数赋予相应的权重,整合构建一个新的综合危害指数IDI (Integrated Damage Index)作为树种对沙棘木蠹蛾的抗性指标,并划分抗虫等级。其中,Ⅰ免疫树种(柳叶沙棘、云南沙棘、榆树、桃树、苹果和杏树)；Ⅱ高抗树种(沙枣、丘依斯克×中国沙棘、棱果、霞光、肋果和太阳沙棘)；m低抗树种(阿亚甘卡、乌兰格木、乌兰格木×中国沙棘、优胜、楚伊和梨树)；Ⅳ感虫树种(浑金、中国沙棘和橙色沙棘)。(2)在野外人为控制条件下,布置不同抗性级别的沙棘品种(树干外罩绿色布料或不罩),通过接入不同处理的沙棘木蠹蛾,以其在不同寄主的着落率为指标,对其寄主选择行为进行研究。结果显示,着落率大小与抗虫等级的划分完全一致,同时也证明了沙棘木蠹蛾在寄主选择过程中,其嗅觉发挥了决定性的作用,反映了沙棘木蠹蛾寄主选择机制是与寄主本身有很大的相关性。寄主挥发物的差别可能是影响沙棘木蠹蛾选择行为的关键因素。(3)触角剪除试验表明,触角是沙棘木蠹蛾感觉系统的重要组成部分,其末端存在着不同类型的感觉器,行使嗅觉、味觉等功能,在寄主搜寻和寄主识别等过程中起着极为重要的作用。完全剪除触角,由于失去了嗅觉功能,沙棘木蠹蛾不能接受寄主挥发物的刺激,导致对寄主的选择没有明确性,这进一步体现出嗅觉在寄主选择中的重要作用。(4)研究沙棘树皮形态特征与抗虫性的关系,结果发现,沙棘木蠹蛾选择为害与树皮颜色、皮孔大小、粗糙程度无关,与树皮紧实程度,裂缝大小相关。(5)探讨树种主干部位和一年生枝条的组织特征的差异与沙棘木蠹蛾危害程度的关系,多元回归分析表明,不同沙棘种(品种)主干部位和一年生枝条的导管密度、木射线宽度、木化细胞半径和皮层石细胞厚度与沙棘抗虫性并不密切相关。更多还原

【Abstract】 Holcocerus hippophaecolus Hua, Chou, Fang et Chen (Cossidae, Lepidoptera) is the insect pest appeared in "Three Norths Areas" of China in recent ten years. It damaged the seabuckthorn forest to death about 160 thousand hm2. The disaster become the main restricting factor. In recent years, studies and reports of H. hippophaecolus focused on biology and zoology, species and suppression function of natural enemies, development and utilization of sexual pheromone, countermeasures both at forest management and chemical control etc. Howerver, the study on insect-resistant mechanism of seabuckthorn has not been mentioned before, which plays important role to explore the causes of population eruptive, therefore provides scientific evidence for regional control of H. hippophaecolus.The study was carried out by adopting the methods both bioassay in wild and observation in laboratory. We probe resistance levels of different tree species to H. hippophaecolus and analyse relationships among morphological structure, organizational structure and resistance mechanism by using method of tissue anatomy. The major findings are as follows:(1)Combine artificial infection in cage and natural infection in wild, aiming for the baring-egg frequency and ovipositing rate of H. hippophaecolus at different tree species, then giving corresponding weight based on the correlation coefficient among them, so as to construct a new Integrated Damage Index as indicators for setting resistance levels. There were four levels: i Immune tree species (Hippophae salicifolia, Hippophae rhamnoides subsp. yunnanensis Rousi, Ulmus pumila, Prunus persica, Malus pumila and Prunus armeniaca); ii High resistance tree species (Elaeagnus angustifolia, XiuyisikeXzhongguoshaji, Lengguo, Xiaguang, Leiguo and Taiyang); iiiLow resistance tree species(Ayaganka, Wulangemu, Wulangemu X Zhongguoshaji, Yousheng, Chuyi and Pyrus sorotina); ivSusceptible tree species (Hunjin, Hippophae rhamnoides L. subsp. sinensis Rousi and Chengse).(2)Seabuckthorn varieties with different resistance levels, some of whose trunks were covered by green cloth while others were not, were planted under a controlled natural condition. Then the experiment taking the landing rate of H. hippophaecolus on different hosts as index, was carried out to observe the host selection behavior of H. hippophaecolus which was used by different treatments. The results showed that size of landing rate are completely consistent with the divided resistance levels. Besides, it can be proved that olfactory plays a decisive role in the host selection process of H. hippophaecolus, which reflects that host selection mechanism of H. hippophaecolus is greatly linked to its hosts. Additionally, it is showed that the difference of host volatiles affecting the selection behavior of H. hippophaecolus is the key factor.(3) The experiment on removing antennae indicates that antennae is an important part of the sensory system of H. hippophaecolus, and there are various types of sensilla implicating olfaction and gestation that are very important in host location and identification distributed on the terminal of antenna. Remove the antennae completely, H. hippophaecolus can not accept the stimulation of host volatiles because of missing olfactory function, which lead to the indeterminacy of its host selection. Further more, it suggests that the olfaction plays an important role in host selection.(4) The study on relationship between bark morphology and insect resistance of seabuckthorn indicates that the damaging behavior of H. hippophaecolus has nothing to do with hosts’bark color, stomata size, roughness, but is associated with their compaction degree and crack size.(5)The relationship between the damage degree of H. hippophaecolus and the difference of tissue characteristics of tree trunk and one-year-old branches was investigated. The multiple regression analysis shows that vessel density, wood ray width, lignification cell radius and Cortex sclerotic cell thickness of the tree trunks and annual branches of different seabuckthorn species (varieties) are not closely correlated with the resistance of H. hippophaecolus更多还原