海水处理对向日葵幼苗生长及叶片一些生理特性的影响

采用海水水培的方法，比较了淡水、20%和40%海水处理对向日葵(Helianthus annuus L.)幼苗生长速率、根冠比、脯氨酸、丙二醛(MDA)含量和保护性酶超氧歧化酶(SOD)及过氧化物酶(POD)活性的影响。结果表明：20%海水处理显著地促进根系生长和根冠比的增加，大大地缓解了叶片的膜脂过氧化作用(使之降至与对照相当的水平)，而40%海水明显抑制向日葵生长；脯氨酸在处理4 d后显著积累，40%海水处理后脯氨酸与MDA变化曲线相关性较强，表明脯氨酸的积累在本实验中表现为活性氧伤害的结果；40%海水处理对食葵叶片造成的过氧化伤害比油葵大，但食葵比油葵的自身修复受伤害膜系统的能力强。

Effect of Seawater on the Growth and Leaf Oxidative Metabolism of Sunflower Seedlings

Study of sunflowers (Helianthus annuus L.) exposed to salt stress of seawater was infrequently reported. In this study, effects of 20% and 40% seawater on the growth, ratio of root to shoot, contents of proline and MDA, activities of SOD and POD in the seedlings of two sunflower cultivars, a oil sunflower(G101B) and a edible one, were investigated. The results showed that the root growth rate and r/s ratio of two sunflower cultivars were significantly increased in 20% seawater. While membrane lipid peroxidation was not obvious in contrast to control seedlings. Proline content increased remarkably in two sunffower cultivars after a 4-day treatment with 40% seawater, and its change was significantly consistent with that of MDA. These results indicated the occurrence of oxidative stress under the treatwout. Based on the higher level of MDA, there was a more serious oxidative stress in the edible sunflower than in the oil sunflower after a 4-day treatment with 40% seawater, but the former had a greater ability of membrane reconstruction.