Drought resistance in seedlings of Catalpa bungei cultivars.

In order to provide a theoretical foundation for afforestation in arid and semi-arid regions and to exploit the Catalpa resource,drought resistance in one-year-old seedlings of 7 cultivars of Catalpa bungei and C. ovata were studied using a completely random design with treatments of 0,40,80,and 120 g·L-1 and three replications by applying simulated drought stress with PEG 6000. Using method of subordinate function and a system cluster analysis,growth and physiological indexes related to drought resistance were measured and evaluated. Results showed that 'Guangye'and 'Ginsi' cultivars,and C. ovata had higher drought resistance followed by 'Zhou 2' and 'Nanyang' and finally the stock,'Yuanchang',and 'Yu 1'. Drought resistance of 'Zhou 2' and 'Nanyang' decreased with the increasing drought stress,but drought resistance of the other cultivars were not greatly changing in any content of drought stress. The method of subordinate function and system cluster analysis revealed that 40 and 80 g·L-1 PEG 6000 were suitable for evaluation of drought resistance with C. bungei in the seedling stage.