中文摘要：

以6周龄拟南芥生态型Columbia-4为材料，在0（CK）、5、10、15、20、25、30、35mmol·L^-1草酸（0A）胁迫48h后，测定过氧化氢酶（CAT）、超氧化物岐化酶（SOD）、过氧化物酶（POD）和苯丙氨酸解氨酶（PAL）的活性及丙二醛（MDA）的含量，以探讨OA胁迫对模式植物拟南芥活性氧代谢及PAL活性的影响．结果表明：相比于CK，PAL活性极显著地升高；SOD活性也受到诱导，在20mmol·L^-1OA胁迫下，SOD活性最高；CAT和POD的活性与cK相比，受到抑制，在20mmol·L^-1OA胁迫下，二者被抑制的程度最高，并且POD活性较CAT活性被抑制的程度更大；MDA含量与OA浓度呈良好的线性关系（Y=0．0279x＋1.6567，R^2=0．9222^＊＊＊），表明OA浓度越高，对拟南芥细胞的伤害越大．可见，OA有可能通过抑制CAT和POD的活性，导致H2O2等活性氧自由基的累积和膜脂过氧化作用，最终引起对拟南芥叶片的毒害．

英文摘要：

The activities of antioxidative enzymes and phenylalnine ammonialyase （PAL） were determined under oxalic acid （OA） stress. The leaves of 6-week-old Arabidopsis thalinana were used as material. The activities of catalase （ CAT）, superoxide dis- mutase （SOD）, peroxydase （POD）, PAL and the contents of malondialdehyde （MDA） were determined after OA （0, 5, 10, 15, 20, 25, 30 and 35 mmol · L^-1 ） treated for 48 h. Compared with control, PAL activity was significantly increased （ P 〈 0.01 ）, and SOD activity was also induced by OA, and it reached the peak value under the stress of 20 mmol· L^-1 OA; the activities of CAT and SOD were both inhibited, and they reached the minimum value under 20 mmol · L^- 1 OA stress, and POD was inhibited more severely than that of CAT. There is good linear correlation between the content of MDA and OA （y = 0. 0279x ＋ 1. 6567, R2 = 0.9222 ^＊＊＊ ）. Oxalic acid inhibited the activities of CAT and POD, leading to the accumulation of reactive oxygen species and lipid peroxidation, finally impaired leaf cells of Arabidopsis.