Abstract

DISTRIBUTION OF ASCORBIC ACID IN THE DEVELOPING ANTHERS OF CUCUMIS SATIVUS L.

Dr. Jyoti S. Kawalekar*

Abstract

Ascorbic acid has be en found to be present and essential to the norm al functioning of all cellular units in the higher plants and animals including subcellular structure such as ribosomes and mitochondria. In plant s, it appears to play an essential role in photosynthesis and is formed rapidly in all of the most active cells during the initial germination stage in seeds. Ascorbic acid (vitamin C) is an abundant component of plants. It has proposed functions in photosynthesis as an enzyme cofactor (including synthesis of ethylene, gibberellins and anthocyanins) and in control of cell growth. In relation to cell growth, ascorbate is a cofactor for prolyl hydroxylase that posttranslationally hydroxylates proline residues in cell wall hydroxyproline-rich glycoproteins required for cell division and expansion. It occurs in all cell compartments including the cell wall. Additionally, high ascorbate oxidase activity in the cell wall is correlated with areas of rapid cell expansion. Emerging research results indicate that ascorbate, existing widely in plants as the abundant micromolecule substance, fulfils its essential roles in series of physiological processes such as plant defense against oxidization, co-factor of key enzymes, plant cell division, cell expansion, growth and development, and senescence (Smirnoff N (1996) and Horemans N, Foyer CH, Potters G, Asard H (2000b)). Ascorbate, at least in some plant species, is also the substrate for the biosynthesis of oxalate and tartrate (Loewus F.A., Loewus MW (1987) and Loewus F.A. (1999)). However, the multifunction of ascorbate makes it complicated to decipher its exact role under certain physiological process. Thus, there is need to increase our understanding of this enigmatic molecule since it could be involved in a wide range of important functions from antioxidant defense and photosynthesis to growth regulation. Present investigations pertain to the histochemical assessments of general Ascorbic acid and their role in the differentiation of tissues during anther development in Cucumis sativus L.

Keywords: Ascorbic acid Cucumis sativus L., anther tissue, histochemistry.