哈密瓜内生细菌菌群密度及分布动态

Study on the Dynamic Change of Population Density and Distribution of Endophytic Bacteria in Hami Melon Plants in Xinjiang

分离哈密瓜植株组织中的内生细菌,对不同品种、不同栽培环境、不同组织器官、不同生育期的哈密瓜内生细菌的菌群组成、菌群密度的动态分布特点进行研究。结果表明:哈密瓜不同品种、不同种植地区、不同组织器官、不同生育期内生细菌的菌群密度有较大差异。抗病品种中的内生细菌显著高于感病品种。哈密瓜各组织中,种子的内生细菌最多,其次为根,再次为茎、叶片、叶柄,果实中最少。在不同生长阶段,随着哈密瓜生育期的延长,内生细菌数量变化呈“高-低-高”的变化特点,即从苗期到花期,植株内生细菌总量下降,至成熟期数量显著增加的特点。对所分离的内生细菌进行菌群分析表明,哈密瓜内生细菌包括芽孢杆菌属、黄单胞菌属、假单胞菌属、欧文氏菌属、葡萄球菌属、鞘氨醇单胞菌属、黄色单胞菌属和类芽孢杆菌属(Paenibacillus)等,其中芽孢杆菌属出现的频率最高,在所分离的哈密瓜品种中都是优势菌群,约占总分离菌株的54.58%;但菌群多样性在不同哈密瓜品种和种植地区间差异不显著;种子中类群最少,随着植株生长,类群增加。

In this study, some bacteria strains are isolated from different tissues of Hami melon collected from different regions in Xinjiang. The dynamic changes of population density and distribution of endophytic bacteria in different eultivars and tissues of Hami melon at different growth stages in different planting areas are studied. The results reveal that the population density of endophytie bacteria in disease-resistanee cultivars of Hami melon plants is significantly higher than that in susceptible eultivars. Among the organs of Hami melon plants, the population density of endophytie bacteria is the highest in seeds, then in roots, stems, leaves and petioles, and it is the lowest in fruits. The population density of endophytic bacteria decreases from seedling stage to florescence, and increases significantly at autumn. The genera of endophytic bacteria in Hami melon plants are analyzed. The results show that the endophytic bacteria with high frequency in Hami melon plants are Bacillus spp. , Xanthomonas spp. , Pseudomonas spp. , Erwinia spp. , Staphylococcus spp. and Sphingomonas, Flavimonas, Paenibacillus. Arnong these genera, Bacillus is a dominant genus with an isolation frequency of 54.58%. There is no significant differenoe in the community diversity of endophytic bacteria among the different culfivars of Hami melon plants and the planting regions. It is also found that the genera are the least in seeds, and they increase with plant growth.