Effect of Shading Treatments on Photosynthesis of Drepanostachyum luodianense

Taking the seedlings of D.luodianense(Yi et R.S.Wang)Keng f.as materials,effects of three shading treatments of low shading(LS,the relative light intensity was 74.32%),moderate shading(MS,the relative light intensity was 44.83%)and severe shading(SS,the relative light intensity was 18.57%)on the photosynthesis and the parameters of optical response characteristics of D.luodianense were studied by light control experiment,with natural light as the contrast(CK,the relative light intensity was 100%),in order to investigate shade tolerance of endangered plant of D.luodianense.The results showed that,compared with CK,under LD net photosynthetic rate,maximum net photosynthetic rate,apparent quantum efficiency and light use efficiency(LUE)of D.luodianenseincreased a lot,while light saturation point(LSP),light compensation point(LCP)and dark respiration rate declined.Under MD or SD,gas exchange parameters like net photosynthetic rate,apparent quantum efficiency,maximum net photosynthetic rate,light saturation point,light compensation point and dark respiration rate and the other light response parameters of D.luodianense were gradually decreased with the strengthening of shading stress,but LUE increased significantly.These results showed that D.luodianense could well adapt to low shading environment and moderate shading conditions were more advantageous to the growth and development.In the further aggravating shading environment,D.luodianensecould enhance directly LUE,LCP and LSP to maintain a certainlevel of photosynthesis and reduce energy consumption,so that the rapid accumulation of carbon could be realized and so as to strengthen the ability to resist.Therefore,D.luodianense had strong adaptability to moderate shading and severe shading environment.