外源苯甲酸对平邑甜茶幼苗根系膜脂过氧化的影响

大多数果树都存在连作障碍(重茬、再植病、忌地现象)现象,其中苹果(Malus)、李(Prunus salicina)、桃(Prunus)等连作障碍更为严重.杨兴洪等(1991)调查苹果重茬地成活率只有40%～60%,美国华盛顿州10年间苹果产区因重茬每公顷损失4万美元,山东省烟台大量苹果园已经表现并将面临更大面积的苹果连作问题.

Effects of Benzoic Acid Application on Membrance Lipid Peroxidation in Roots of Mains hupehensis Seedlings

Malus hupehensis was used as experiment materials. This experiments were conducted to explore the effects of benzoic acid on the productivity of superoxide (O_2~(-·)) , the contents of malondialdehvde (MDA) and sulfhydryl group activity(-SH) , antioxidant enzyme activity and mineral elements in roots of M. hupehensis seedlings. The results showed that there was no significant difference between the treatment of 5 mg·kg~(-1) (soil) benzoic acid and CK in above parameters. With 25 mg·kg~(-1) (soil) and 125 mg·kg~(-1) (soil) benzoic acid treatments, O_2~(-·) and MDA contents increased in the early period and then declined; -SH content decreased during the treatment time; activities of SOD and POD increased firstly, then decreased, CAT activity decreased firstly and then slightly reversed, but lower than that of CK; SOD, POD and CAT had a similar trend,activities of roots increased under 5 mg·kg~(-1) (soil) benzoic acid , while they were inhibited by 25 mg·kg~(-1) (soil) and 125 mg·kg~(-1) (soil) benzoic acid; mineral elements were decreased. Benzoic acid in low concentration promoted antioxidant enzyme activity,-SH content, and uptake of mineral elements, reduced O_2~(-·) and MDA contents. In conclusion, benzoic acid of 5 mg·kg~(-1) (soil) had no effects on Membrance Lipid Peroxidation and Antioxidant enzymes in roots of M. hupehensis seedlings; at 25 mg·kg~(-1) (soil) and 125 mg·kg~(-1) (soil), benzoic acid increased Membrance lipid Peroxidationd, decreased activity of antioxidant enzymes of roots, and damaged integrity and stability of cell membrane in M. hupehensis seedlings, meanwhile,contents of mineral elements were decreased.