ALLELOPATHIC IMPACT OF PHYLLODE OF ACACIA AURICULAEFORMIS A. CUNN. ON PHOTOSYNTHETIC APPARATUS OF RICE LEAVES DURING SEEDLING GROWTH

摘要

Allelochemicals are the secondly metabolites of one plant that influence the growth and development of neighbouring plants and microbes. Generally these allelochemicals are phenolics, organic acids, steroids, alkaloids etc. which enter into the environment by various means such as leaching, volatilization, root exudation etc. Acacia auriculaeformis A. Cunn a member of family Mimoceae are generally planted in and around the crop fields whose phyllodes directly and /or indirectly control the growth anddevelopment of crops. Laboratory experiments were carried out to find out the impact of aqueous leachate of Acacia auriculaeformis phyllode on structure and function of chloroplasts of two rice cultivars (Pratikhya and Khandagiri) during their seedlinggrowth. It was noticed that all concentrations of aqueous leachate of phyllodes (2,4,6,8 and 10%) drastically checked the synthesis of chlorophyll pigments (a,b and total), carotenoids and protein in chloroplasts and structural disorganization of photosynthetic assembly as evidenced from absorption characteristics of the organelle. The detrimental effect of allelochemicals has been attributed to their ability to form reactive oxygen species (ROS) which are well known for causing degradation of differentbiomacromolecules.