多效唑对银中杨、白榆和白桦抗旱性的影响

Effect of Paclobutrazol on Drought_Resistance of Populus alba × Populus berolinensis, Ulmus pumila, and Betula platyphylla

在干旱胁迫条件下，植物会产生一系列的生理变化，从而影响其生长发育（杨建昌等，2004；时连辉等，2005）。从研究的对象来看，主要集中在应用高效、低毒植物生长调节剂提高农作物或1年生植物的抗旱性上（曹翠玲等，2004；周凤珏等，2004），而在林木，尤其是城市绿化树种上的应用研究较少（彭立新等，2004；温国胜等，2004）。多效唑是一种高效低毒的植物生长延缓剂。国内外对多效唑在农作物、果树、蔬菜、花卉上的作用和应用已进行了广泛研究（Kraus et al．，1995；汪志辉等，2003；周凤珏等，2004；阮龙等，2005；

Foliar spraying with different concentrations of paclobutrazol was conducted to two-year-old seedlings of Populus alba × Populus berolinensis, Ulmus pumila, and Betula platyphylla under drought stress. Results showed that paclobutrazol could lower the decrease of leaf water potential and soluble protein content, increase water use efficiency of seedlings of these three species to different extent, and also had various influences on free proline content and membrane-lipid peroxidation. The synthetic evaluation of drought-resistance of seedlings from different treatments showed that the seedlings pretreated with paclobutrazol had distinct drought-resistance. Low concentrations of paclobutrazol made a great impact on the improvement of drought-resistance of P. alba × P. berolinensis seedlings, while high concentrations of paclobutrazol had a favorable regulative effect on the drought-resistance of U. pumila seedlings, and for B. platyphylla seedlings a relative good result only be obtained with paclobutrazol at the concentration of 750 mg ·L^-1.