青枯菌(Pseudomonas solanacearum)在番茄抗、感病品种根部的吸附、侵入和繁殖

 采用不同的方法接种和利用扫描、透射电镜观察,研究不同致病力的青枯菌对番茄抗病及感病品种根部的吸附、侵入与繁殖。发现番茄抗病品种与感病品种的植株体内在菌体数量上有明显差异,而与青枯菌对番茄根部的吸附关系不显著。电镜观察发现青枯菌强致病力菌株菌体能以游离的形式存在于番茄感病品种根部的细胞间隙中,并能降解植株细胞壁、破坏原生质膜;青枯菌强致病力菌株菌体在抗病品种根内和青枯菌强致病力菌株在抗病及感病品种根内均被番茄植株细胞壁吸附,并且被细胞壁周围的浓密物质所包围。

ADSORPTION,PENETRATION AND MULTIPLICATION OF THE PATHOGEN (PSEUDOMONAS SOLANACEARUM) IN THE ROOTS OF TOMATO PLANTS

Bacterial wilt of tomato caused by P. solanacearum is an important vascular wilt disease. Attachment and entry of the bacteria into the host and progression to vascular tissues can be considered as an important step of infection by this pathogen. The adsorption, penetration and multiplication in the roots of susceptible and resistant varieties of virulent and/or avirulent strains were studied with different inoculation methops and electron microscopy. The resistance of the tomato varieties was due to their inhibition of the pathogen's multiplication, and not due to the adsorption of the pathogen to host's root surface. Upon entering the root tissue, the virulent bacteria existed freely in the intercellular space of the susceptible variety and finally disrupted the cell walls and plasmalemma of the plant root epidermal cells. In the tissues of the resistant varieties, the virulent bacteria were enclosed by the dense material near the cell wall. The same phenomenon occurred in the resistant or susceptible varieties with the avirulent bacteria.