SUMMARY OF THE SIGNIFICANT CONTRIBUTION TO SCIENCE AND TECHNOLOGY DEVELOPMENT
Prof. A.N Purohit has mainly worked on ecophysiology of tree species and physiology of high altitude medicinal plants.
Prof. Purohit demonstrated for the first time that the indeterminate species can be made determinate. Based on this observation, he proposed that it is the channelization of food factors and the reproductive hormones, which controls the indeterminate or determinate nature of the plants. Prof. Purohit has shown a close relationship between photosystem I and onset of generative phase, which he has explained in terms of the energy requirement as a prelude to generative phase. He has proposed that evocation in leaves leading to the onset of floral induction starts with biophysical process(es) relating to the excitation of molecules in response to light and oxidation- reduction state of reaction centre pigments.
Prof. Purohit worked out the dynamics of shoot elongation and expansion showing recurrent growth pattern and reported appreciable histological changes in the shoot apex during longest period of dormancy and onset of reproductive phase, which was the first report of such developmental process in trees. This he further confirmed by a simple experiment in which he grew dogalus fir seedlings in high concentration of CO2 which induced bud dormancy leading to differentiation of cone like structure in one year old seedlings of this plant.
He studied the effect of CO2 enrichment and reported that high concentration of CO2 inhibits flowering in classical short day plants and induces flowering in long day plants and even the phytocrome mediated responses in flowering are associated with the presence of CO2 during red light interruption. He also reported for the first time that CO2 enrichment also affects viral multiplication.
Prof. Purohit and his associates have added valuable information to the scientific field with respect to the applied value of variations in leaf temperatures in plants. They have identified two groups of tree species; namely .under. and .over temperature. tree species. According to their findings .under temperature. species have higher survival potential on highly exposed subtropical mountain slopes with high temperature and irradiance. Based on physiological parameters, he worked out the superiority index for selection of tree species for plantation in mountains and their fuel wood value index.
Prof. Purohit.s study on large cardamum and mandarin based agroforestry systems in Sikkim revealed: (1) acceleration of nutrient cycling under the influence of N2 . fixing trees, (2) greater release of nutrients from non-N2-fixer letter and (3) solubilization of secondarily fixed phosphorus by Alnus and Albizia. These findings have great significance in agroforestry model development.
After joining Garhwal University, Prof. Purohit initiated work on the physiology of high altitude plants. He established a High Altitude Plant Physiology Research Centre with its alpine field station at 13000-ft elevation at Tungnath. The work conducted at this Centre has reveals that high altitude species are less sensitive than the low altitude species to the environmental stresses. He has reported “Pseudomonocotyle” and regulatory role of Cotyledons in the growth of epicotyle in some of the alpine dicot species. The germination studies of alpine plants made by Prof. Purohit and his associates have helped in germinating many endangered species and establishing them in nature in the alpine field station at Tungnath. He and his associates have come up with the cultivation technology for Aconites, alpine and sub-alpine plants of very high medicinal value, where yield is increased 10 to 12 fold.
Prof. Purohit, as Director, also helped Govt. of India in establishing G.B. Pant Institute of Himalayan Environment and Development. The Institute has its units all over Indian Himalaya. With the assistance of all the staff members of the Institute, Prof. Purohit prepared a based document entitled .Action Plan for Himalaya. which forms the base document for the sustainable development of the Himalayan region. During his tenure, he initiated number of programmes in Himalayan region. .Badrivan Restoration. with the help of pilgrims was one of the unique programme which has been cited internationally as a model for restoration of religious places all over the World.
FOR THE VALUABLE SCIENTIFIC CONTRIBUTION IN INDIAN MOUNTAINS MADE BY PROF. PUROHIT, HE WAS AWARDED PADMA SHRI BY THE PRESIDENT OF INDIA IN 1997.