Effects of paclobutrazol on drought resistance of Lolium perenne ‘Bomber’under different growing conditions

Lolium perenne cv. ‘Bomber’ is widely applied as turf grass species in the garden lawn of north China. In the present study, the physiological characteristics of ‘Bomber’ with different concentrations of PP333 treatments under drought stress in both greenhouse and the field were evaluated to provide reference for solving the practical water shortage problems in turfgrass management. The results revealed that the physiological indices of ‘Bomber’ leaves after PP333 application had no significant difference under short stress period (10 d), while had significant differences under moderate stress period (20 d) and long stress period (30 d). During drought stress, the leaf relative water content (RWC) declined, whereas the relative conductivity, malondialdehyde (MDA) content and free proline content increased and super-oxide dismutase (SOD) activity fluctuantly changed. Based on these comprehensive responses of physiological indices, PP333 application with the concentration of 200 mg·L-1 can improve the drought resistance of L. perenne. Under the same degree of drought stress, the seedling damage in the field was far less than those in the greenhouse, which indicated that the actual drought tolerance of turfgrass was stronger than the experimental results under the greenhouse drought condition.