BIOGENIC SILICA (PHYTOLITH) PRODUCTION PATTERN OF COTYLEDONARY, FIRST TWO AND MATURE LEAVES OF HOLOPTELEA INTEGRIFOLIA PLANCH., SEEDLINGS

Holoptelea integrifolia Planch. is a large deciduous tree belonging to family Ulmaceae. Silica is absorbed in the form of monosilicic acid from the soil through their roots and become deposited in the cells of cotyledons, first two leaves and mature leaves. Silica is one of the most beneficial elements for all biological forms. It enhances the yield and quality of certain crops and help plants to overcome various biotic and abiotic stresses. Present study demonstrates the silica deposition pattern in cotyledons, first two leaves and mature leaves of H. integrifolia. In all three leafy forms silica is mostly deposited in the hairs, hair bases, tracheids, epidermal cells, and corkwarts. Hairs and hair bases are of different shapes and sizes in cotyledons, first two leaves and mature leaves of seedlings. Silicified hairs are unicellular, multicellular or glandular having smooth walls or armed with papillae. The highest frequency of silica deposition is found in mature leaves followed by first two leaves and cotyledons. These silicified hairs protect the plants against herbivores and check evaporation. They also inhibit the growth of pathogens and protect the delicate tissues from solar radiation.