www.tjprc.org editor@tjprc.org IMPACT OF PLANT GROWTH HORMONE, INDOLE-3-ACETIC ACID (IAA) ON THE ORGANIC CONSTITUENTS OF SILKWORM, BOMBYX MORI L V. LAKSHMIKANTHAM & D. BHARATHI Department of Sericulture, Sri Padmavati Mahila Visvavidyalayam (Women’s University), Tirupati, Andhra Pradesh, India ABSTRACT The impact of indoe-3-acetic acid (IAA) fed through mulberry on the organic composition of silk gland of silkworm larvae has been studied. The increase in the total proteins, total carbohydrates, glycogen, Trehalose and decrease in the free glucose content of silk gland indicates that IAA favored stimulatory effect on synthesis of silk proteins which might influence on the quality of silk. The increase in protein content of silk gland indicates either its active uptake from haemolymph for utilization at cellular level or decreased proteolysis of silk gland. The increase in the total carbohydrate content of silk gland indicates that IAA favored stimulatory effect on cocoon crop production and seem to have improved the biosynthetic activities of silk gland. The decreased free glucose content observed in the silk gland of IAA treated larvae indicates its possible increased re-cycling of glucose during IAA supplemented conditions. The increase in glycogen content might have resulted from the increased breakdown of glycogen and or decreased synthesis under the influence of IAA. The increase in the biochemical composition was correlated with the observed increase in the body weight and silk output. KEYWORDS: Silkworm, Bombyx mori L, Indole-3-Acetic Acid (IAA), Total Proteins, Total Carbohydrates, Free Glucose, Glycogen and Trehalose Objectives • To study the effect of indole-3-acetic acid (IAA) on the organic constituents of the silkworm Bombyx Mori L. • To test the efficacy and final suitability of indole-3-acetic acid (IAA), so as to take the findings from lab to land • To identify the effective use of indole-3-acetic acid (IAA) for the benefit of sericulture industry. INTRODUCTION The plant hormones are the growth regulators that regulate or control the growth and development in the plants. The first plant hormone to be identified was the auxin (Paul et al, 1979). Auxin appears to be a master hormone, exercising regulatory action over many different sorts of plant processes and probably over many of the other plant hormones (Bonner and Galston, 1951). Auxin has more effect than the other growth regulator, gibberelines (Bernad et al, 1973). The only one compound, Indole-3-acetic acid (IAA) has been positively identified as a major naturally occurring auxin synthesized in plants (Bernard et al, 1973). IAA is believed to be derived from tryptophan through decarboxylation and deamination reaction to Indole-3-acetaldehyde which is then oxidized to IAA. This occurs chiefly in young growing tissue such as stem tips, young leaves, flowers, embryos and root tips (Paul et al, 1979). International Journal of Agricultural Science and Research (IJASR) ISSN(P): 2250-0057; ISSN(E): 2321-0087 Vol. 4, Issue 5, Oct 2014, 37-44 © TJPRC Pvt. Ltd.