Faba bean (Vicia faba L. cv. ‘Giza 2’) seeds were cultivated in untreated (effluent) and treated (influent) sewage water, while control seeds were cultivated in tap water. The ultrastructure of 9-week old plant leaves and roots was investigated. The effects of the presence of biotic agents (fungal endophyte and/or a fungal pathogen(s)) and heavy metals were also demonstrated. Chloroplasts from plants growing in effluent water exhibited ill-defined thylakoids in a very dense stroma whereas those from plants growing in influent sewage water displayed a normal ultrastructure compared to control stroma. Moreover, transmission electron micrographs showed other effects such as advanced vacuolation, dilated rough-endoplasmic-reticulum cisternae and separation of the plasma membrane from the cell wall. Dense cytoplasm rich in ribosomes and lipids, small vacuoles with electron-dense granules was also observed. The common host reactions to the invading fungus were also investigated. Intracellular penetration of the epidermal, cortical, and mesophyll cells by fungal hyphae was also observed. |
