苹果树腐烂病菌有性型单孢菌株生物学特性及其无性后代致病力研究

发布时间：2018-09-11 11:55

【摘要】：苹果树腐烂病是由黑腐皮壳属(Valsa spp.)引起的一种为害苹果树的枝干、果实等多个部位并对树体造成重大危害的病害之一。该病可使苹果树主干枯死,树势衰弱,发生严重时可造成果园大量减产,果实品质严重下降,甚至毁园等现象。近年来该病在我国苹果产区普遍发生,给我国苹果产业造成了严重的经济损失。综合已有文献发现,关于苹果树腐烂病病原菌种类鉴定、无性型生物学特性及防治方面的报道较多。但是对苹果树腐烂病菌有性型生物学特性、是否可以形成无性后代及其在苹果树腐烂病发生流行中的作用以及其与无性型的关系缺乏研究。因此本研究针对以上现存问题,采用单孢分离技术对苹果树腐烂病菌有性型进行分离、其单孢菌株的生物学特性研究及有性型单孢菌株的无性型后代与原无性型菌株间的比较,得出以下结果:1苹果树腐烂病菌有性型单孢分离通过单孢分离共获得了16株苹果树腐烂病菌有性型单孢菌株,在PDA培养基上,于25℃、黑暗条件下培养7d长满培养皿,菌落正面与背面均为乳白色,菌丝浓密,且连续培养30d未产生子实体。有性型单孢菌株具有致病力,且其致病力显著低于无性型菌株,在30d左右,有性型单孢菌株在离体枝条上形成了无性子实体。2苹果树腐烂病菌有性型单孢菌株生物学特性研究有性型单孢菌株的生长温度范围为15~32℃,最适生长温度为25℃。有性型单孢菌株均能在p H范围为3~9的条件下生长,最适生长p H为6,酸性条件更适宜其菌丝生长。光照可以明显促进有性型单孢菌株菌丝的生长。有性型单孢菌株对各供试碳源利用程度基本相同,其对葡萄糖的利用程度最大,可为最佳碳源,其次是麦芽糖和乳糖。有性型单孢菌株可能存在较高效率的氮代谢途径,氮源种类对有性型单孢菌株的生长影响很大,对酵母膏的利用程度最高,对牛肉膏和蛋白胨的利用程度次之,硫酸铵利用程度最低。3有性型单孢菌株无性后代培养性状观察苹果树腐烂病菌有性型单孢菌株随机配对,在供试的5种培养基上,25℃暗培养不能形成子囊壳。部分组合在菌落交界处产生了黑色分生孢子器,随培养时间的延长有分生孢子角溢出,部分组合未产生分生孢子器且在菌落交界处出现了明显的裂痕,苹果树腐烂菌有性型单孢菌株存在体细胞不亲和性反应。在PDA培养基上产生分生孢子器的数量显著高于ABA培养基,分生孢子成熟时间为14d。有性型单孢菌株产生的分生孢子器黑色,球形,单个或多个腔室,腔室之间的分界不明显,其无性后代的分生孢子相比原菌株分生孢子萌发力和致病力较弱。4苹果树腐烂病不同菌株潜育期的比较在各外界因素的影响下有性型单孢菌株无性后代的潜育期显著长于原无性型菌株的潜育期。苹果树腐烂病菌的潜育期随保湿时间的延长而缩短,温度对苹果树腐烂病潜育期影响显著,在25℃时潜育期最短,苹果树腐烂病在嫩枝上潜育期最短,在光暗交替条件下(12h黑暗+12h光照)时潜育期最短。
[Abstract]:Canker disease of apple tree is one of the diseases that damage the branches and fruits of apple trees caused by Valsa spp. It can cause the main trunk of apple trees to wither and weaken the tree vigor. When it occurs seriously, it can cause a large number of orchards to reduce yield, fruit quality to decline seriously, and even destroy the orchard. In recent years, the disease has been widespread in China's apple producing areas, causing serious economic losses to the apple industry. It has been found that there are many reports on the identification of pathogenic fungi of apple rot, the biological characteristics of asexual types and their control. But whether the sexually biological characteristics of the pathogenic fungi of Apple rot can be formed or not. In view of the above problems, this study used single spore isolation technology to isolate the sexual types of apple tree rot fungus, the biological characteristics of its monospore strains and the asexual progeny of the characteristic monospore strains. The results were as follows: 1. A total of 16 isolates of the sexual monospores of the apple rot fungus were obtained from the single spore isolation. On the PDA medium, at 25 C and under darkness conditions, they were cultured for 7 days. The colonies were milky white on the front and back, with dense hyphae and continuous growth. No fruiting bodies were produced after 30 days of culture. The pathogenicity of the sexually monosporic strains was significantly lower than that of the asexual strains. The asexual fruiting bodies were formed on the isolated branches of the sexually monosporic strains at about 30 days. 2 Biological characteristics of the sexually monosporic strains of Apple rot fungus The optimum growth temperature was 25, and the optimum growth temperature was 32, and the optimum growth temperature was 3 6550 The best carbon source was maltose and lactose. Sexual monospore strains might have a more efficient nitrogen metabolism pathway. The types of nitrogen sources had a great influence on the growth of sexual monospore strains. The yeast extract had the highest utilization, followed by beef extract and peptone, and ammonium sulfate had the lowest utilization. Observation on the Culture Characters of Clonal Progenies of Sexual Monospore Strains The number of conidia produced in PDA medium was significantly higher than that in ABA medium. The conidia matured for 14 days. The conidia produced by the sexually monosporic strain was black and spherical. The germination and pathogenicity of the conidia of the progeny were weaker than those of the original strain. 4 Comparison of the incubation period of different strains of Apple rot under the influence of various external factors, the incubation period of the progeny of the clonal strain was significantly longer than that of the original strain. The incubation period of Apple rot fungus was shortened with the extension of moisturizing time. Temperature had a significant effect on the incubation period of Apple rot. The incubation period of Apple rot fungus was the shortest at 25 C. The incubation period of Apple rot fungus was the shortest at 25 C. The incubation period of Apple rot fungus on tender branches was the shortest, and the incubation period was the shortest at alternating light and dark
【学位授予单位】：甘肃农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S436.611.11

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