不同的植物对铝胁迫的生理响应不同, 因而对铝毒的耐性也不相同。设置5种铝浓度，进行砂培法处理，研究了4种我国南方红壤广泛分布的草本植物——牵牛(Pharbitis nil)、望江南(Cassia occidentlis)、光头稗(Echinochloa colonum)和合萌(Aeschynomene indica)的种子萌发、光合色素、脯氨酸含量、丙二醛(MDA)含量、可溶性糖(SS)含量、质膜透性(MP)、过氧化氢酶 (CAT) 活性以及过氧化物酶 (POD)活性的变化。结果表明铝对4种植物的生理特性都有明显的影响。4种植物的种子在10 000 mg·L－1 Al3+处理条件下都不能萌发。2 000 mg·L－1 Al3+处理都不利于4种植物的生长，与对照相比，2 000 mg·L－1 Al3+处理时4种草本植物叶绿素和叶绿素总含量显著降低(p<0.05)；MDA含量和MP显著增加(p<0.05)；脯氨酸含量极显著增加(p<0.01)；POD和CAT活性极显著降低(p<0.01)。中低铝(80和400 mg·L－1)处理时，牵牛和合萌与对照相比，MP和MDA含量降低，POD和CAT活性升高；望江南的反应与牵牛和合萌的反应相反；光头稗在80 mg·L－1 Al3+处理时，与牵牛和合萌的变化一致，在400 mg·L－1 Al3+处理时，则相反。植物在中低铝处理条件下，通过维持较高的POD和CAT活性和脯氨酸、叶绿素含量，较低的MP和MDA含量来增加其对铝的耐性。
The aim of this study was to determine the effects of Al stress on the physiological responses of four herbaceous plants and to analyze the differences in their physiological responses. Four southern herbaceous plants, Pharbitis nil, Cassia occidentlis, Echinochloa colonum and Aeschynomene indica, which are distributed in the red soils of South China, were used to study the seed germination, chlorophyll content, levels of proline, malondialdehyde (MDA), membrane permeability (MP) and soluble sugar (SS), and activities of peroxides (POD) and catalase (CAT) in their leaves under five Al treatments (0, 80, 400, 2 000, 10 000 mg·L-1) with the sand culture method. The results showed significant effects of Al on the physiological characteristics of these four herbaceous plant species. The seeds of all four species could not germinate at the 10 000 mg·L-1 Al3+ treatment and were disadvantageous to growth under the 2 000 mg·L-1 Al3+ treatment. When compared to the control, the 2 000 mg·L－1 Al3+ treatment significantly (p<0.05) reduced the contents of chlorophyll a and chlorophyll a+b (p<0.05), promoted levels of MDA and MP (p<0.05), very significantly increased the content of proline (p<0.01) and depressed activities of POD and CAT (p<0.01). In the 80 mg·L－1 and 400 mg·L－1 Al3+ treatments, levels of MDA and MP in P. nil and A. indica leaves decreased, and the activities of POD and CAT increased compared to the control, but variations in C. occidentlis leaves showed an opposite response. Changes in E. colonum leaves were similar to P. nil and A. indica under 80 mg·L－1 but opposite to those under the 400 mg·L－1. These species maintained higher activities of POD and CAT, higher contents of chlorophyll and proline, and lower contents of MDA and MP, thus improving their tolerance to Al stress under low and medium Al treatments.