Anatomical Changes and Development of Cecidomyiid Leaf Gall of Quercus leucotrichophom-Himalayan White Oak

摘要

Entomogenous galls (zoocecidia) are pathologically developed abnormal growths which originate as a result of chemical or mechanical insect stimuli. Leaves of Quercus leucotrichophora A. Camus were leathery, dull green, white and serrate. The tree is affected with many types of leaf galls caused by different types of insects. The order Diptera has the largest number of galls making insects. Many cecidomyiidae genera like Asphondylia, Lasioptera and Dasineura are known to cause plant galls. An unknownItonididae (cecidomyiid) caused pouch leaf galls on the tree Anatomy and ontogenesis of the leaf gall and normal leaf of Q. leucotrichophora were studied. The neo-formed tissues showed a highly constructive anatomy. Trichomes and sclerenchyma were characteristic structures against the natural enemies of the gall inducer. Nutritive tissue was present in the gall whose cells were similar to meristematic or parenchymatous cells. These cells showed a characteristically high physiological activity suitable to gall inducer's nutrition. The gall maker's stimulus supported the differentiation of parenchyma into sclerenchyma instead of a totally distinguished tissue. Thus, the plant galls offer the best opportunity to reconstruct steps in a modified, but geometrical biological structure that arises solely through the trigger messages received from an alien organism.