土壤pH值对烤烟叶片光合特性及体内保护酶活性的影响

采用盆栽土培法，研究了pH值对烤烟叶片光合特性及体内保护酶活性。结果表明，生长初期，pH6．5～7．5处理的烟叶内叶绿素、光合速率都较高，旺长期达到高峰；土壤pH值与POD活性呈负相关，而SOD、CAT活性和MDA含量则是随着pH值的升高而增加。成熟期，随土壤pH值的升高，CAT、POD、SOD活性增加；MDA含量则表现为，pH4．5～6．5处理的呈增加趋势，pH7．5～8．5处理的呈下降趋势，pH8．5处理的MDA含量最低。在成熟期各处理中，光合速率则以pH8．5最高。

Effect of Soil pH on Photosynthesis Characteristics and Activity of Protective Enzymes in Flue-cured Tobacco Leaves

In early growth period, the content of chlorophyll and the photosynthesis rate were higher in leaves treated at the pH value between 6.5 and 7.5, then reached maximum at the vigorous growth stage. In early growth period, soil pH had negative correlation with the activity of POD declined when the pH value was up from 4.5 to 8.5 ; but the activity of SOD and CAD as well as the content of MDA increased with the rising of pH value. At mature stage, with the rising of soil pH , the activity of CAT and POD declined while the activity of SOD increased; the content of MDA had an increasing tendency while the pH value was up from 4.5 to 6.5 and declining tendency while the pH value was up from 7.5 to 8.5 and it reached its minimum value on soil pH 8.5. At mature stage the photosynthesis rate were higher in leaves at various pH value.