杂交鹅掌楸不同无性系对Pb胁迫的生理响应及抗性比较

Comparison of resistance and physiological response of different clones of hybrid tulip tree (Liriodendron chinense× L. tulipifera) to Pb stress

采用盆栽法研究了4个杂交鹅掌楸（Liriodendron chinense ×L．tulipifera）无性系扦插苗对土壤Pb胁迫的生理响应与抗性差异。研究结果表明，Pb胁迫能抑制杂交鹅掌楸无性系扦插苗生长，使叶片失绿变黄、根系活力下降，且1．0mg·g^-1 Pb胁迫的抑制效果更明显。随Pb胁迫时间的延长，4个杂交鹅掌楸无性系扦插苗叶片的相对电导率和MDA含量均持续增加，胁迫结束时，相对电导率和MDA含量分别是对照的1．45～1．92倍和2．23～3．23倍。叶片的POD活性和游离脯氨酸含量在整个Pb胁迫过程中呈先升后降的变化趋势；不同无性系的SOD活性变化存在一定差异。随着Pb浓度的增加，杂交鹅掌楸不同无性系扦插苗各生理指标的变化幅度各异。比较发现，无性系NE60对Pb胁迫的抗性最强。

Physiological response and resistance of four clone stecklings of hybrid tulip tree （Liriodendron chinense × L. tulipifera） to Pb stress in soil were studied by pot culture method. The results showed that growth of hybrid tulip tree stecklings was restrained by Pb stress, leaves became yellow and root activity decreased, and the inhibition effect was more obvious under Pb stress of 1.0 mg·g^-1. Along with prolonging of Pb stress time, relative conductivity and MDA content of four clone stecklings increased gradually, and were 1.45 - 1.92 times and 2.23 - 3.23 times to the control respectively at the end of Pb stress. POD activity and free proline content increased firstly then decreased during whole period of Pb stress, and SOD activity changes varied among different clone stecklings. With gradually increasing of Pb concentration, physiological indexes of four clone stecklings changed inconsistently. It is concluded that NE60 is the most resistant clone to Pb stress among four clones.