Namita Sharma, Ashish Tewari and Shirsh K. Singh
Abstract
In this study seedlings of banj oak (Quercus leucotrichophora A. Camus) were subjected to four drought cycles of I 5, 30, 45 and 60 days and were given normal watering to study water relation in response to water stress in a green house located in Nainital (between latitude 29° 24'N and longitude 79° 25'E) at 2016m. Osmotic adjustment and consequent capacity for pressure potential maintenance under drought appears to be an important mechanism of adaptation in this group (Parker et al. 1991); Bahari et al., I 985).The study gave useful information on the extreme level of drought to which seedlings of this species could survive and the drought adaptation mechanism it follows.The seedling failed to survive the 60 days drought in the green house but the seedlings that had been subjected to a 45 day drought had a predawn water potential of 3.1 MPa and showed on osmotic adjustment of -2.1 MPa at full turgor and 2.5 MPa at zero turgor and a pressure potential of 3.8 MPa.The study revealed that osmotic adjustment is a major drought adaptive mechanism of this oak.