【作者】 池高亮；

【导师】 刘君昂； 吕全；

【作者基本信息】 中南林业科技大学 ， 森林保护学， 2010， 硕士

【摘要】 小蠹虫和真菌之间的共生是森林生态系统内一种普遍的生态学现象,是生物长期协同进化的结果。在我国北方红脂大小蠹发生区,多种小蠹虫和天牛广泛存在并在部分地区造成明显的危害。由于小蠹虫与长喙壳类真菌伴生关系复杂多样,相关真菌种类繁多,且随小蠹虫和伴生长喙壳类真菌种类及寄主树木的差异而不同,同时目前对小蠹虫及其伴生长喙壳类真菌的关系缺乏系统性的研究,所以小蠹虫与其伴生的长喙壳类真菌对寄主植物的危害机制等都尚需更深层次的研究。本实验以小蠹虫及其伴生长喙壳类真菌为研究对象,进行长喙壳类真菌的分离鉴定、生物学特性、致病力测定等研究。(1)小蠹虫及天牛危害调查。从5个标准样地调查结果中可以看出,小蠹虫危害最为严重的是安家庄林场,林木危害率最高达到了10-35%,小蠹虫种类也最为丰富,共在安家庄林场采集到5种小蠹虫,这可能与安家庄林红脂大小蠹危害较为严重,且树木采伐较为严重,林地树势整体较弱有关；灵空山林场和铁桥林场的小蠹虫危害程度中等,分别为7-21%和8-20%；在野峪沟林场和顺县林场,小蠹虫的危害率最低,分别是6-11%和3-10.5%,同时这2个地方的长喙壳类真菌的分离频率也比较低。(2)小蠹虫伴生长喙壳类真菌的分离与鉴定及致病性测定。从采集到的86个标本的344块组织(韧皮部、边材)或虫体碎片共分离到103个菌株(strains),分离率约30%。根据菌株形态特征初步鉴定共得到超过5个属的真菌种类。通过对其形态特征的观察及该菌ITS的序列测定,并与Genbank中经Blast搜索获得的部分菌株构建分子系统发育树。基于形态特征和分子系统发育树,最后确定4种长喙壳类真菌,他们分别是Leptographium. sinoprocerum, Leptographium. truncatum, Leptographium. Koreanum和Ophiostoma ips。将分离得到的菌株采用干部接种和蘸根接种两种方法进行致病力测定实验,结果表明其中Leptographium. truncatum和Leptographium. koreanum两种长喙壳真菌具有较强致病性。(3)长喙壳类真菌在油松死亡中的可能作用分析及小蠹虫防治对策建议。小蠹虫伴生长喙壳真菌表现出较强的致病性,结合小蠹虫攻击寄主行为习性的改变可能有利于增强这些伴生菌致病力的分析,小蠹虫伴生菌在降低油松的抗性及其生长势上起到重要的作用。这些伴生菌协同小蠹虫,以及温室效应、异常气候条件的诱因等多种因素的共同作用下,导致寄主油松树势衰退甚至死亡。针对小蠹虫的猖撅危害,加强小蠹虫危害监测并综合采用有关如生物、化学、物理等防治措施,及时控制和防止小蠹虫危害蔓延；保护和改善林分环境,保护和利用小蠹虫天敌,以及采取生物防治等措施,从而使小蠹虫危害得到可持续治理,促进经济和生态协调发展。更多还原

【Abstract】 Bark beetles and fungus coexisting in forest ecosystem is a common ecology phenomenon in long-term co-evolution of biology.In the North China where Dendroctonus valens widespread, a variety of bark beetles exist and cause significant damage in some areas. The relationship between bark beetles and associated ophiostomatoid fungi are complex and diverse,and there are a wide range of related fungi, changing with different host trees. Meanwhile, it lack systematic research about the relationship between bark beetles and the associated ophiostomatoid fungi currently, so the damage mechanisms of bark beetles and their associated ophiostomatoid fungus on the host plants are still need further study.The object in this experiment are bark beetles and their associated ophiostomatoid fungi, conducting on isolation and identification of ophiostomatoid fungi, and their biological characteristics and pathogenicities.(1) Surveies of Bark beetles damages. It can be seen from the investigation result of the five standard plots, the most serious damages was discovered in the AnJiaZhuang Forest Farm, and the highest damage rate has reached 10-35%. Also the most abundant species were collected in this Farm—5 species of bark beetles, which may be connected with serious harms caused by bark beetles, seriously harvesting of trees and the weak forest tree vigor;bark beetle damages in LinKongShan and TieQiao Forest Farm was moderate, and the rates were 7-21% and 8-20%; the lowest bark beetles damages rate occured in YeYuGou and HeShun Country Forest Farm, were 6-11% and 3-10.5%, at the same time, the two places of the ophiostomatoid fungus separation frequency are lower.(2) Isolation and identification of ophiostomatoid fungus associated with bark beetles, and Pathogenicity testing.344 phloems (sapwoods) and worm fragments from 86 samples collected were isolated into 103 strains, and the isolation rate was about 30%. There are more than five species of fungi testing by the preliminary identification. Observing their morphologies and testing ITS sequences, blast searches with Genbank obtained in part by the strain of building a phylogenetic tree. Based on morphological characteristics and molecular phylogenetic tree, it determines four kinds of ophiostomatoid fungus. They are Leptographium. sinoprocerum, Leptographium. truncatum, Leptographium. koreanum and Ophiostoma ips. The strains isolated are tested by two methods of trunk inoculation and root inoculation, and the results show that the Leptographium. truncatum and Leptographium. koreanum have strong pathogenicity.(3) The possible role of ophiostomatoid fungus in the death of Pinus. tabulaeformis, and the control countermeasure to bark beetles. As these associated fungus display strong pathogenicity, combined with habits of bark beetles attacking host, it may make for the analysis of the pathogenicity of associated fungus. The ophiostomatoid fungus associated with bark beetles played an important role in reducing the pine’s resistance and growth. The ophiostomatoid fungi collaborated with bark beetles, effected by global warm, abnormal weather conditions and other factors, lead to host pine tree decline and even death.In order to eliminate severe harm of the bark beetles, strengthen its monitoring, we can consolidate preventive measures of biology, chemistry, physics and other control method, timely control and prevent the spread of bark beetle damage; protect and improve the forest environment, protect and utilize the natural enemies of bark beetles and make use of biological measures to manage bark beetle damages sustainability and coordinate the development of economy and ecology.更多还原