An Ultrastructural Study on the Development of Silicified Tissues in the Leaf Tip of Barley (Hordeum sativum Jess)

The development of silicified tissues in the tip of the fourthand fifth leaf of 7-week-old barley plants grown in nutrientsolution was investigated by transmission electron microscopy.The pattern of silicification was similar in the epidermal cells,sclerenchyma cells and intercellular spaces. Silica granulesfirst appeared around the periphery and eventually filled theentire cell lumen or space. The granules then polymerized toform a solid mass. The walls of the sclerenchyma cells alsobecame silicified but to a less extent than those of the epidermalcells, in which silicification sometimes occurred prior to thatin the lumen. The results are discussed in relation to the chemistry of silicaand possible mechanisms of silicification. Hordeum sativum Jess, barley, silica bodies, opalines, epidermal cells, sclerenchyma, ultrastructure