土壤pH值对烤烟叶片生理生化特性的影响

烟草生长初期,超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量与pH增长呈正相关,而过氧化氢酶(CAT)和过氧化物酶(POD)活性则随着pH的增加而下降,pH值6.5和7.5时叶绿素含量和净光合速率(Pn)较高,旺长期达到高峰;生长后期,各处理的MDA含量和POD活性最高,SOD、CAT活性最低.各pH值处理的叶片中,叶绿素含量、Pn下降,比叶重达到高峰,但pH 8.5下的烟叶中叶绿素含量高,Pn大,比叶重较小.pH 6.5和7.5下的烟叶中蛋白质和可溶性糖总体含量高于其它pH的.烟碱含量在pH 5.5时最高,pH 8.5时最低.

Effect of Soil pH on Physiological-biochemical Characteristics in Flue-cured Tobacco (Nicotiana tabacum L.) Leaves

In the early growth period of tobacco (Nicotiana tabacum L.), the activity of superoxide dismutase (SOD) and the malonaldehyde (MDA) content had positive correlation with soil pH value. The activities of catalase (CAT) and peroxidase (POD) decreased with the rising of pH value. The chlorophyll content and the net photosynthetic rate (Pn) were higher in leaves treated at pH 6.5 and 7.5, they reached maximum in the vigorous stage. In the late growth stage, the CAT content and the POD activity of each treatment reached maximum, while the activities of SOD and CAT were minimum. The chlorophyll content and the Pn declined and the specific leaf weight reached maximum in the leaves treated with all pH values. The chlorophyll content and the Pn were higher and the specific leaf weight was lower in the leaves treated with pH 8.5. The protein and soluble sugar contents in the leaves treated with pH 6.5 and 7.5 were higher than the other treatments. The nicotine content was the highest in leaves treated with pH 5.5 and was the lowest treated with pH 8.5.