(University of Ruhuna. Kamburupitiya, 1998) Wijeratne, M.A.; Fordham, R.; Anandacumaraswamy, A.
The diurnal variations of water relations of the tea plant were studied using potted young tea plants with particular reference to drought tolerance. Glasshouse experiments showed that the diurnal changes of plant water relations of tea are largely governed by the environmental factors such as solar radiation and saturation vapour pressure deficit. Accordingly, diffusive resistance and relative water content of both drought tolerant and susceptible clones were low during the mid day. Drought tolerant tea clones possess higher stomatal diffusive resistance, lower transpiration rates and higher leaf turgidity over the day time. Moreover, they conserve moisture by reducing transpiration rate at the latter part of the day earlier than that of drought susceptible clones.
