Anther and pollen development in garden pea and cultivated lentil

Abstract

After conventional fixation procedures and embedding in low-viscosity resin, anthers were studied using light and electron microscopy. Wall development is dicotyledonous. Sporogenous tissue undergoes one mitosis before meiosis. Entry of pollen mother cells (PMCs) into meiosis is indicated by formation of a prominent polar nucleolar cap. Cytomictic channels form between PMCs in early prophase I. In Pisum sativum the middle lamella breaks down between meiocytes. The quartets are surrounded by an extensive callose wall within which primexine starts to form. Callose dissolution is centripetal. Once microspores are released from the callose wall tectate exine development continues and the pollen cytoplasm vacuolates. Mature cytoplasm of the pollen exhibits zonation. No plastids were observed in the generative cell. Endothecial cells develop extensive thickenings. In Pisum the thickenings are primarily cellulosic whereas in Lens culinare besides cellulose some lignin may be present. Various developmental stages of the secretory tapetum have been followed. Tapetal senescence begins at about microspore mitosis. Only minor variations in anther and pollen development occur between Pisum and Lens.