套袋与未套袋苹果果实表皮及心部真菌种群结构与变化动态

Community structure and temporal dynamics of fungi in cuticle and core of bagging and un-bagging apple fruits

2011年在山东海阳,2013年在蓬莱和栖霞选取当地常规管理的苹果园,采用传统组织分离法对套袋苹果、未套袋苹果的果实表皮及心部组织进行真菌分离并进行形态学和分子生物学鉴定。对不同时期采集的套袋及未套袋果实表皮与心部的真菌种类、菌落数量、组织分离率、多样性、相似性系数、相对分离频率等指标进行统计分析。结果表明,两个年度内从果实表皮共分离获得真菌43属,从心部获得真菌31属,相对分离频率较高的真菌包括:链格孢Alternaria spp.、枝状枝孢Cladosporium cladosporioides、镰孢菌Fusarium spp.、青霉菌Penicillium spp.等。研究结果表明:果实套袋后,在果实表皮定殖真菌的种类减少,多样性降低,而数量增加,组织带菌率升高;随果实生长,套袋果实表皮上的真菌种类与未套袋果实表皮真菌种类的相似度逐渐降低;7、8月份,套袋果实表皮上真菌种类明显减少,至8月底,套袋果实表面只有链格孢等少数几种优势真菌定殖。果实套袋后,定殖于果实心部的真菌种类和数量有所波动,套袋果和未套袋果上所分离真菌的相似度有所降低;5月底自果实心部分离真菌的种类和数量与9月底所分离真菌的种类和数量差异不大。

Using traditional tissue isolation method, community structure and temporal dynamics of fungi from bagging fruits and un-bagging fruits were investigated in apple orchards in Haiyang in 2011, and Penglai and Qixia in 2013. The isolated fungi were identified according to morphology and ITS sequences. Species richness, colony number, colonized ratio, diversity index,coefficient of similarity and isolation frequency of fungi in cuticles of bagging fruits, core of bagging fruits, cuticles of un-bagging fruits and core of bagging fruits were calculated and analyzed. The investigation showed that, within two years, 43 and 31 genera of fungus were isolated from cuticle and core of apple fruits respectively. Alternaria spp., Cladosporium cladosporioides, Fusarium spp. and Penicillium spp. showed higher isolation frequencies. Species richness and diversity index of the fungi colonized on cuticles decreased while tissue colonized ratio and colony number increased after fruit bagging. Coefficient of similarity of species richness of the fungi colonized on cuticles of bagged and un-bagged fruits decreased gradually with growing of apples. Species richness of fungi colonized on bagged fruit cuticles significantly decreased at July and August. Only a few dominant fungi, such as Alternaria spp., can be found on cuticle of bagged fruits at the end of August. Species richness and colony number of fungi colonized in the core of fruits maintain a stable level in long term after fruit bagging. Coefficient of similarity of fungus species richness in the core of bagged and un-bagged fruits decreased with an unobvious variation. There was no significant difference in species richness and colony number of fungi isolated from the core of fruits between the end of May and September.