Histological study of Ethylene induced Gum Duct formation in Gum Karaya (Sterculia urens Roxb.)

Abstract

Gums and resins occupy a prime place among Non-Wood Forest Produce (NWFP/NTFP) and are known to mankind since time immemorial. Gums are important natural biopolymers demand from biological system under stress situation i.e. disease injury to bark etc. being used as a principal components in food, pharmaceutical industries and play a key role in social and livelihood of tribal communities. Gums are metabolic by-products of plant tissues either in normal course or often as a result of disease or injury to the bark or wood of certain plants and it cannot be re-enter with plant system. The process of gummosis related to biotic and abiotic stress of tree plant and plays significant role in production of biopolymers (gum/resin). The impact of gum enhance Ethephon was found significantly superior, regarding the production of biopolymers. Gum Karaya (Sterculia urens Roxb.) is a dry deciduous tree belonging to the family Sterculiaceae distributed throughout India and Chhattisgarh. Therefore, the physiological tool was used to impose artificial stress via various concentration of Ethephon (slow releasing substance of ethylene) as gum enhancer in stem of gum Karaya to find out the mechanism of gummosis and compared with mechanical tapping method undertaken in ICAR Network Project. The biological (anatomical), studies were done via taking the sample of soft (sapwood) after injecting the gum enhancer Ethephon at different time intervals. It can observed that the application of Ethephon enhance the process of gummosis, due to formation of gum duct. Karaya gum is the dried exudate obtained from trees of Sterculia species. The gum duct formation was observed in histological analysis of bark section within 2hrs of Ethephon treatment in gum karaka. The histological changes indicated that the gum ducts lysigenouslyare present in the pith and cortex of the young stem of Sterculia urens but absent in the xylem.