遮荫和氮素添加对芒萁光合特性与抗氧化酶活性的影响

Effects of Light Intensity Gradient and Nitrogen Addition on Photosynthetic Characteristics and Antioxidant Enzyme Activities of Dicranopteris dichotoma

为探究芒萁对环境资源变化的响应,采用盆栽控制试验,通过搭建遮荫棚设置3种光强和2种氮素水平,分析光强和氮素对芒萁光合特性和抗氧化酶活性的影响。结果表明:未施氮且2层遮荫条件下芒萁最大净光合速率最高,光能利用范围比1层和3层遮荫大,为19.2~1 138.7μmol/(m^2·s);施氮处理提高了1层和2层遮荫条件下的最大净光合速率和光能利用范围,3层遮荫条件下净光合速率的降低由气孔限制引起。未施氮处理,芒萁丙二醛含量、超氧化物歧化酶活性、过氧化物酶活性、过氧化氢酶活性在3层遮荫条件下显著高于1层和2层遮荫;施氮与未施氮相比,1层和3层遮荫条件下丙二醛含量降低,2层遮荫条件下丙二醛含量显著上升,且超氧化物歧化酶、过氧化物酶、过氧化氢酶均显著增加。可见,2层遮荫条件下最适合芒萁的生长,3层遮荫条件膜质过氧化最严重,施氮减弱了1层和3层遮荫下的膜质过氧化程度。

To explore the response of Dicranopteris dichotoma to the change of environmental resources, 3 light intensities and 2 nitrogen levels were set up to form treatments by a pot experiment. The effects of light intensity and nitrogen addition on photosynthetic characteristics and antioxidant enzyme activities of D. dichotoma were studied. The results showed that without nitrogen application, Amax was the largest under L2 shading, and the light utilization range was 19.2-1 138.7 μmol/(m2·s), larger than that under L1 and L3 shading. The Amax and utilization range of light energy under L1 and L2 shading conditions were improved after nitrogen application. And the decrease of A under L3 shading was caused by stomatal limitation. Without nitrogen application, MDA content, SOD activity, POD activity and CAT activity were significantly higher than those of L1 and L2 under L3 shading. Compared with non-nitrogen application, MDA content decreased under L1 and L3 shading, increased significantly under L2 shading, SOD, POD and CAT increased significantly. In conclusion, L2 shading was the most suitable condition for the growth of D. dichotoma, and L3 shading was the most serious condition for membrane peroxidation. Nitrogen application reduced the degree of membrane peroxidation under L1 and L3 shading.