Abstract:

The ability of drought resistance of Acer ginnala,Malus baccata,Prunus davidiana and Pyrus ussuriensis was studied under four soil moisture treatments (relative soil moisture content 75%、61%、46%、35%, respectively) by planting seedling in pots in greenhouse. The water parameters were calculated by using Pressure-Volume technique,and the drought resistance of four species was comprehensively evaluated. The results showed, under drought conditions, P. ussuriensis was the best in terms of water absorbing;all of four species had some extent of osmotic adjustment and turgor maintenance abilities. A. ginnala, P. ussuriensis, and P. davidiana could adjust osmosis by improving the proportion of bound water to some extent, when the soil moisture content decreased to 61% (for P. davidiana,and A. ginnala) and 46%(for P. ussuriensis), their osmotic adjustment ability by improving the proportion of bound water disappeared. Under drought conditions, P. davidiana and A. ginnala could maintain turgor by improving elasticity of cell wall, while P. ussuriensis and M. baccata maintained turgor mainly by osmotic adjustment. Water stress could increase the abilities of maintaining maximum turgor of P. davidiana, M. baccata and A. ginnala, but decrease the abilities of maintaining maximum turgor of P. ussuriensis. A. ginnala could adapt drought stress by improving the ability of tolerating dehydration, but M. baccata and P. davidiana could not. We concluded that the ability of drought resistance of four species was M. baccata>P. ussuriensis>P. davidiana>A. ginnala by integrating their osmotic potential adjustment and turgor maintaining abilities.

Key words: Water stress, Osmotic adjustment, Turgor maintaining, Drought resistance, Broad-leaved tree species