低温胁迫对4种常绿阔叶植物膜脂过氧化及保护酶活性的影响

选取我国北方4种常绿园林树木大叶女贞、广玉兰、小叶女贞、黄杨的当年生枝条和叶片为试材，采用人工冷冻处理，经过对不同处理温度后各树种叶片的失水率、保护酶的活性、MDA含量和枝条及叶片细胞膜透性等指标进行测定分析。研究结果：表明随着处理温度的降低，各树种叶片和枝条的相对电导率值呈上趋势，在4个树种中黄杨上升得较缓慢，而小叶女贞上升的幅度最高，同一处理温度下，各树种枝条的相对电导率低于其叶片的相对电导率；黄杨MDA含量随处理温度的降低表现为先降低后增加的变化趋势，在-20~0℃之间MDA含量均有所下降，而其他树种MDA总体含量随处理温度的降低表现为增加的变化趋势；各树种叶片SOD酶活性均表现为随着温度的降低呈先升高后降低的变化趋势，但各树种SOD酶活性趋势发生变化的温度不同，而POD酶活性随处理温度的降低基本表现为逐渐降低的变化趋势。根据各项指标测定结果对4种树种的抗寒性强弱进行比较，结果为：黄杨＞广玉兰＞大叶女贞＞小叶女贞。

Effect on Low Temperature Stress on Lipid Peroxidation and ActiVity of Cell Deflense Enzymes of Four Evergreen Broadleaved Tree Species

With the leaf and one-year twig of four evergreen garden tree species as the experimental materials，disposed through low temperature，relative leakage of electrolytes of leafs and twigs，super-oxide dismutase(SOD) activity and peroxidase(POD) activity and malondialdehyde(MDA) content were measured and compared. The results showed that:the relative leakage of electrolytes of leaf and twig increased with decreasing disposed temperature,but the relative leakage of electrolytes of leaf was higher than the twig’s to the same tree species; Mal-ondialdehyde(MDA) contents of Euonymus japonicus Thunb first descended(-20~0℃) then increased but MDA contents of other tree species increased with decreasing disposed temperature; Superoxide dismutase(SOD) activites of tree species first increased then descended but peroxidase(POD) activites descended with decreasing disposed temperature.The cold-resistance ability of the plants were comprehensively judged with all indexes,there were obvious differences among the clones of the ability of cold resistance.The ability of cold resistance on the plants from high to low was Euonymus japonicus Thunb.> Magnolia grandiflora L.> Ligustrum lucidum Ait.> Ligustrum quihoui Carr.