黄芪根腐病病根的显微及超微结构研究

Study on the structure of Astragalus membranaceus roots infected by the root rot disease

利用石蜡切片和超薄切片方法,以黄芪(Astragalus membranaceus)的健康植株作为对照,研究了黄芪根腐病病根的解剖结构、致病真菌的侵入方式以及在根内的分布,为进一步从细胞水平研究黄芪根腐病致病机理提供理论依据.结果表明:病根与健根的基本解剖结构没有明显的区别,主要差异是病根中有入侵的真菌,大量染色较深的菌丝结分布在薄壁组织细胞中;真菌侵入时不破坏周皮,其菌丝穿过周皮组织细胞进入韧皮薄壁组织,在薄壁细胞中形成菌丝结,并逐步扩展成一定的侵染区域,继而向下一层薄壁组织细胞内侵入,严重时甚至侵染到木质部.真菌的生长和增殖抑制了细胞的生长.

The anatomical structure of Astragalus mernbranaceus roots infected by root rot, the way of pathogenic fungi invaded and the distribution of the fungi in the root are studied by paraffin sectioning and thin sectioning, taking the healthy roots as comparison, the result provide the theory basis for deeply researching the pathogenic mechanism of Astragalusmernbranaceus root rot. The results indicate that the only difference on the basic anatomical structure is that the fungi invade in the diseased roots and many pelotons in parenchymatous cells; The fungi don＇t infect the periderm, they enter the phloem parenchymas through periderm, and then, form pelotons, colonize and infect other cells continuously by means of hypha penetrating the ceil wall, then they continue to infect the next parenchymatous cells, even xylem. The growth and proliferation of the fungi inhibite the growth of cells.