红树植物秋茄内生细菌数量时空变化动态初步研究

Spatiotemporal Dynamic of Endophytic Bacteria in Kandelia candel

分别用吖啶橙染色荧光显微计数法和平皿分离计数法对秋茄内生细菌总量和可培养内生细菌数量的时空变化进行测定。结果表明，秋茄植株根茎叶内均含有大量的内生细菌，其中根茎叶内生细菌总量平均分别为4.35×10^7 ind/g、6.31×10^7 ind/g和5.02×10^7 ind/g；可培养细菌总量平均分别为2.58×10^3 cfu/g、1.76×10^3 cfu/g和4.43×10^3 cfu/g。其时空变化动态为：内生细菌总量根部变化基本平稳，而叶部和茎部均呈峰形变化，其峰值分别出现在5月和7月；可培养细菌数量根茎叶均呈峰形变化，根部峰值出现在9月，而茎叶部峰值均出现在3月。秋茄植株可培养的内生细菌数量占其内生细菌总量比率为（0.02～8.33）×10-4，秋茄植株体内仅有小部分的内生细菌为可培养，绝大多数内生细菌为不可培养或难培养。

In this study, the total number of endogenous bacteria and the culturable endogenous bacteria in Kandelia candel collected from Zhanjiang Donghai island mangrove nature reserve were determined by acridine orange fluorescence microscopy and tablet separation, respectively. Statistical results of four seasons showed that K. candel in vivo owned numerous bacteria. The average total amount of bacteria in roots, stems and leaves were 4.35×10^7 ind/g, 6.31×10^7 ind/g and 5.02×10^7 ind/g successively, and the number of culturable corresponds to 2.58×10^3 cfu/g, 1.76×10^3 cfu/g and 4.43×10^3 cfu/g. Temporal dynamics regularity showed the total amount of endophytic bacteria in roots remained stable, and those in the leaves and stems reached maximum amount in July and May. As for the culturable bacteria, all of the donor materials were peak shape variation, maximum amount in roots appeared in September, and that in stems and leaves both emerged in March. Besides, culturable endophytic bacteria account for 0.002‰-0.833‰ of the total bacteria, It is indicated that the majority of culturable bacteria in the mangrove K candel in vivo were difficult to culture or uncultured. The results of this study would provide the basis for understanding temporal dynamics regularity of endogenous bacteria in mangrove and developing its resources .