Nuclear Ultrastructural Changes of Infected Cell during the Development of Root Nodules Ultrastructural Changes of the Infected Cells in Onobrychis viciaefolia Root Nodules Role of Endoplasmic Reticulum in the Formation of Peribacteroid Membranes Electron Microscopic Observation on the Infected Cells During Pea (Pisum sativum L.) Nodule Senescence A Special Inclusion in the Vacuoles of Vicia sativa Root Nodule Cells Ultra-structure of the Inclusions of the Vacuoles in the Infected Cells of Onobrychis viciifolia Root Nodules Origin and role of the vesicles located near the plasma membranes of infected cells Ultrastructural Changes Of Infected Cell Nuclei during Cell Apoptosis in Onobrychis viciaefolia Root Nodules