广玉兰新品种‘碧翠’的抗寒性评价及抗寒性指标筛选

Evaluation of Cold Resistance of New Variety‘Bicui’of Magnolia grandiflora and Its Screening of Cold Resistance Index

为评价广玉兰新品种‘碧翠’的抗寒性以及筛选抗寒性评价指标,通过低温胁迫对‘碧翠’和‘埃克斯茅斯’抗寒性进行对照研究,测定其离体叶片的生理生化指标,对抗寒性进行综合评价及指标筛选.结果表明:随着温度的降低,两者的相对电导率(REC)和丙二醛(MDA)含量均逐渐升高,SOD活性和POD活性无明显变化规律,可溶性蛋白(SP)和游离脯氨酸(Pro)呈现先上升后下降的趋势,半致死温度(LT 50)均随气温的下降而降低,‘碧翠’LT 50为-3.03℃,‘埃克斯茅斯’LT 50为-4.28℃,与抗寒性综合分析结果相一致,‘碧翠’<‘埃克斯茅斯’.6个抗寒性指标中REC、SP两个生理生化指标是反应抗寒性强弱的较佳指标.

The purpose of this study is to evaluate the cold resistance of new variety‘Bicui’of Magnolia Grandiflora and to screen its indexes of cold resistance.The cold resistance of Magnolia grandiflora‘Bicui’and‘Exmouth’Magnolia grandiflora were studied by low temperature stress,and the physiological and biochemical indexes of their leaves in vitro were measured,and the cold resistance of the two Magnolia varieties was evaluated and selected as well.The results showed that the relative conductivity(REC)and malondialdehyde(MDA)contents of the two Magnolia varieties increased gradually with the decrease of temperature,and the activity of SOD and POD had no obvious change rule.The soluble protein(SP)and free proline(Pro)increased first and then decreased,while the semi lethal temperature(LT 50)decreased with the decrease of temperature.‘Bicui’LT 50 was-3.03℃and‘Exmouth’LT 50 was-4.28℃,which were consistent with the comprehensive analysis of cold resistance:‘Bicui’<‘Exmouth’.The results showed that REC and SP were the better indexes to reflect the cold resistance.