Abstract
Eggplant (Solanum melongena L.) plantlets infected with vesicular-arbuscular mycorrhizal (VAM) fungus (Glomus etunicatum and Gigaspora margarita) were transplanted to a field contaminated with Verticillium dahliae to investigate the disease tolerance of a VAM fungus-infected plant.
1. Eight weeks after transplanting, plant height, number of leaves, leaf size, and proximal diameter of the main stem were larger in VAM fungus-infected plants than in noninoculated plants. The primary flower bloomed later in VAM fungus-infected plants than in noninoculated plants.
2. The rate of VAM fungus-infected portions in a whole root system reached the maximum of 40.8% with Glomus etunicatum 10 weeks after inoculation, whereas it was 40.2% with Gigaspora margarita 8 weeks later.
3. The appearance of verticillium wilt was delayed and reduced by VAM fungus-infection, and the effects were more apparent in Glomus etunicatum than in Gigaspora margarita. VAM fungus-infected plants yielded more fruits than did the noninoculated plants; the incidence of fruit malformation caused by verticillium wilt were smaller, especially in Glomus etunicatum -infected plants.
4. Lignin (stained with a reagent consisting of phloroglucinol and HCl) accumulated in the firstly and secondly branched roots more richly in VAM fungus-infected plants than in noninoculated plants. Observation using transmission electron microscope (TEM) revealed that the secondary cell wall of cortical cells in the thirdly branched roots was thicker in VAM fungus-infected plants than in noninoculated plants.
