中文摘要：

据估计,全世界已有超过40%的耕地为酸性土壤,我国酸雨区覆盖面积、酸性土壤面积分别占国土面积的40%,21%,并有不断上升的发展趋势（刘鹏等,2005）,而在酸性土壤中活性铝浓度会大大增加,成为酸性土壤抑制植物生长的一个主要因素（刘东华等,1995;丁爱芳等,2000）。广西是我国酸雨污染最严重的地区之一,降雨酸度平均pH值为4.9,最小值可降至3左右,土壤对酸雨的敏感度绝大部分属于最敏感和敏感2级（王敬华等,1994;张帆等,2005）,又由于工业化的不断发展、人工林连作及施用肥料等原因,更加剧富铝化酸性土壤的酸化程度,是极易产生活性铝

英文摘要：

Effects of some physiological processes of different fast-growing Eucalyptus clones （Eucalyptus grandis×E. urophylla Guanglin No.9, E. grandis×E. urophylla Guanglin No.12, E. urophylla Guanglin No.4, E. urophylla×E. camaldulensis No.3） were studied under different acid-aluminum treatments using the cultivation method of sand and soil mixture. The levels of acid-Al were respectively pH 3.0＋0 mg·L-1 Al3＋, pH 3.0＋120 mg·L-1 Al3＋, pH 4.0＋0 mg·L-1 Al3＋, pH 4.0＋120 mg·L-1 Al3＋, and the pH 4.8＋0 mg·L-1 Al3＋ served as the control. The results showed that different acid-Al treatments changed membrane permeability, MDA content, protein content, proline content and soluble sugar content of 4 fast-growing Eucalyptus clones. The low pH and high concentration of Al decreased the membrane permeability, increased peroxide level of membrane and influenced synthesis of protein and soluble sugar contents. At the same time, the seedlings cumulated more proline which protected themselves from the stress. Compared to pH 4.8＋0 mg·L-1 Al3＋, the treatments of pH 3.0＋120 mg·L-1 Al3＋ significantly inhibited the seedlings. Based on change ranges of the physiological indexes, E. grandis×E. urophylla Guanglin No.9 showed better adaptation and resistance to the acid-aluminum treatments than other clones. The resistance was ranked as Eucalyptus grandis×E. urophylla Guanglin No.9E. grandis×E. urophylla Guanglin No.12E. urophylla Guanglin No.4E. urophylla×E. camaldulensis No.3 in turn.