Abstract: To study the effect of aluminum stress on the growth of Michelia chapensis seedlings, the seedlings were cultivated with water culture with different Al³⁺ concentration of 0.5 (T1), 1 (T2), 2 (T3) and 0 mmol·L^-1 (CK), and the root length, content of aluminum in the roots’ tip, the activity of POD and CAT, the content of MDA and proline were measured. The results showed that the elongation of M. chapensis root was inhibited significantly cultured with Al³⁺ for 24 hours, with the increasing of the concentration of aluminum, the degree of inhibition was rising. The relative elongation of roots was 84.53%, 63.16% and 54.46%, respectively. The content of aluminum in the root tip of M. chapensis was increased with the increasing of treatment time and aluminum density; after 6 days, the concentration of Al were 63.64, 82.6, 121.69 times of control, respectively. Stressed by the aluminum, the activity of POD and CAT increased with the increasing of time and aluminum density. The activity of POD and CAT in 6th day respectively increased 17.00%—115.21% and 25.11%—49.28% compared with 1st day. The MDA and proline were increased with the increasing of time and aluminum density. In 6th day, MDA in roots cultured in T1, T2, T3 increased 46.13%—59.78%, and proline increased 60.12%—150.85% compared with control. With aluminum stress, the content of aluminum in root tips of M. chapensis increased and elongation of its roots was inhibited; M. chapensis activated antioxydase system to defense the aluminum stress, and generated proline to regulate osmotic pressure.

Key words: Michelia chapensis, aluminum stress, physiological characteristics

摘要： 为研究铝毒对乐昌含笑Michelia chapensis幼苗生长的影响，采用水培法对乐昌含笑幼苗进行铝胁迫实验，设置铝浓度梯度为0 (CK)、0.5 (T1)、1 (T2)、2 mmol·L^-1(T3)共4个处理，定期测定其根长、根尖铝含量、POD和CAT活性、MDA和脯氨酸(Pro)含量。结果表明，铝胁迫明显抑制乐昌含笑根的伸长生长，随着Al³⁺浓度的增加，抑制程度加剧，T1、T2、T3与CK对照比较，相对伸长率分别为84.53%、63.16%和54.46%；根尖铝含量随处理时间延长和铝浓度增加而增加，处理6 d时T1、T2、T3根尖铝含量分别是CK的 63.64、82.60、121.69倍；POD、CAT酶活性与处理时间和铝浓度呈正相关，各处理6 d时POD活性比处理1 d提高17.00%～115.21%，CAT活性提高25.11%～49.28%；MDA和Pro含量变化随着胁迫时间和铝溶液浓度的增加而增加，处理6 d 时T1、T2、T3的MDA含量比CK对照增加46.13%～59.78%，Pro含量增加60.12%～150.85%。在铝胁迫条件下，乐昌含笑根尖铝含量增加，根的伸长生长受抑制，细胞膜膜质过氧化程度增加；乐昌含笑可通过激活体内抗氧化酶系抵抗铝胁迫，同时产生脯氨酸调节细胞渗透势。

关键词: 乐昌含笑, 铝胁迫, 生理特性