Influence of Changes Weather Conditions on Physiological and Biochemical Characteristics of Darjeeling Tea (Camellia sinensis L.)

Photosynthesis is one of the most important processes on earth. Life as we know it would not have existed without the process, the sun is the ultimate source of energy on earth and green plants through the process of photosynthesis are able to convert solar energy in to photochemical energy which is stored in the form of carbohydrate, providing food for all other heterotrophic organisms including human. The experiment was carried out at Sungma Tea Estate, Darjeeling during 2013-14 to study the effect of climatic conditions on physiological and biochemical parameters of Darjeeling tea cultivation. We had determined net photosynthesis (Pn), stomatal conductance (gs), transpiration (E), water use efficiency (WUE) and leaf water potential (ψL) in tea during the sunny, cloudy weather, under shade tree, rainy and foggy weather. The data correlated with environmental parameters such as air temperature, rainfall, Relative humidity, photosynthetically active radiation (PAR) and vapour pressure deficit. The maximum photosynthesis (12.54 µ mol m-2 s - 1 ) was recorded in cloudy when humidity was high, air temperature; soil moisture and photosynthetically active radiation (PAR) were moderate. In rainy day, higher temperature prevailed but Pn was minimum (3.60 µ mol m-2 s -1 ). Foggy weather leaves received much less PAR than the requirement, hence recorded the lowest rates of Pn (6.65 µ mol m-2 s -1 ). Water use efficiency (0.59 µ mol/m mol-1 ) was lowest in rainy weather, which increased with shade, showing flexibility in adaptation to different light environment. Higher values of gs (0.61 mol m-2 s -1 ) were recorded during rainy weather and lowest value observed in sunny (0.15 mol m-2 s -1 ) weather. Higher value of E was recorded during rainy and lower in foggy weather. Maximum leaf water potential was recorded in rainy and foggy weather as compared to sunny. The chlorophyll content (Chl) was found highest in rainy followed by shade and foggy weather while it was lowest in sunny days. Tea shows considerable flexibility in its adaptation to different light environments as shown with physiological and biochemical changes.