中文摘要：

【目的】分析酸铝处理下4个不同耐铝型速生桉无性系[巨尾桉9号（G9）、巨尾桉12号（G12）、韦赤桉3号（G3）、尾叶桉4号（G4）]叶片内源激素中脱落酸（ABA）、生长素（IAA）、赤霉素（GA3）、玉米素（ZR）的变化趋势，为进一步揭示速生桉对铝毒害的响应机制及选育耐铝型速生桉优良无性系提供参考。【方法】采用砂土培育法对桉树幼苗进行酸铝处理4个月后，应用问接酶联免疫法（ELISA）测定幼苗叶片中ABA、IAA、GA3、ZR4种内源激素的含量，利用坐标综合评定法对各无性系的抗逆能力进行排序。【结果】酸铝处理对4个桉树优良无性系幼苗ABA产生积累作用，对IAA、GA3和ZR等产生抑制作用，且pH值越低、铝处理浓度越高，作用效果越明显，以120mg／LA1^3＋pH3．0的处理效果最显著；幼苗叶片的ABA／IAA、ABA／GA，、ABA／ZR3个平衡指标表现出显著的升高趋势，通过内源激素平衡指标综合评定排序，耐铝性最差的尾叶桉4号的平衡指标增加幅度分别是耐铝性最强的巨尾桉9号的9．2、7．3、8．3倍。【结论】4个桉树优良无性系叶片内源激素问的协调能力与耐酸铝抗性成正比关系。巨尾桉9号对酸铝逆境处理的适应性最好，其ABA含量最低，IAA、GA3、ZR含量最高，各指标变化的幅度较小，受到的抑制作用影响最小，而耐铝性最弱的尾叶桉4号内源激素对酸铝处理的敏感性较强，受到抑制作用最大。

英文摘要：

[Objective]The change trends of ABA, IAA, GA3 and ZR in leaves of four fast-growing Eucalyptus clones [ Eucalyptus grandis × E.uropbylla （ G9 ） , E.grandis × E. urophylla （G12）, E.urophylla （ G4 ） , E.urophylla × E. eamaldulensis （G3）] under acidic aluminum stress were analyzed to reveal the response mechanism to aluminum poison and breeding aluminum-tolerant Eucalyptus clones. [ Method ] After watering the four fast-growing Eucalyptus clones seedlings with exchangeable aluminum in acidic solutions in sand soil for four months, the endogenous hormones in leaves were determined by ELISA. The coordinate synthetic assessment method was used to evaluate the resistance ability based on endogenous hormone proportion. [Result]The different acid-aluminum treatments caused the accumulation of ABA and the inhibition of IAA, GAs and ZR for all tested Eucalyptus clones, and lower pH and higher aluminum concentration showed more obvious effects, especially for 120 mg/L A1^3＋ and pH 3.0 being No.1. The ratio of ABA/IAA, ABA/GA3 and ABA/ZR in leaves had an increase trend and the increment in G4 was 9.2, 7.3 and 8.3 times higher than G9, respectively. [Conclusion]The coordination ability of endogenous hormones in leaves of 4 Eucalyptus clones was positively correlated to acid-aluminum resistance. With the lowest ABA content and highest IAA, GAs and ZR contents, G9 showed the best adaptability and resistance to acid-aluminum with low variation range, while hormones in leaves of G4 with weakest resis- tance was more sensitive to acid-aluminum and inhibited more.