Histochemical changes in Piper nigrum Linn leaves infected with galls caused by Diptera

Abstract

Piper nigrum Linn. (Black pepper) belongs to the family Piperaceae and an economically and medicinally important spice and is a native of Southern India. The gall tissues have shown various structural and physiological changes in the host tissues. The normal and gall tissue showed differential behaviour in terms of the metabolites and enzymes. The Diptera comprises a large group of insects including the common flies, mosquitoes, gnats and midges are characterised by the position of only the mesothoracic pair of wings. Some of them are predaceous, others feed on nectar or plant sap and decaying animal and vegetable matter and few others are blood sucking. When feeding on plant tissues these insects and mites inject or secrete a chemical substance into the plant that causes the plant to grow abnormally and produce a gall. Stimulus for gall formation is usually provided by the feeding stage of the insect. The remain in the gall as inquilines until the completion and maturity of their life stages and emerges from the exit holes. In present investigation, The intensity of starch, cellulose, carbohydrates, proteins, lipids, lignin, tannins and the enzymes viz. acid phosphatase, peroxidase and polyphenol oxidase was observed in diseased leaf of Piper nigrum and estimated and the results have been discussed in the light of pathogenicity, induced by Diptera.