Effects of different nitrogen concentrations on growth and physiological characteristics of Cinnamomum migao seedlings

ObjectiveEffects of different nitrogen concentrations on growth and physiological characteristics of Cin-namomum migao seedlings were studied to provide reference for cultivation and management of C. migao seedlings.MethodC. migao seedlings were cultured in sand in greenhouse,treated by four different nitrogen concentrations,name-ly 1.0 mmol/L(N1 treatment),4.0 mmol/L(N2 treatment),8.0 mmol/L(CK)and 16.0 mmol/L(N3 treatment). Morphologi-cal,physiological and biochemical indexes of C. migao seedlings were measured under different nitrogen concentrations.ResultThe results showed that different nitrogen concentrations could affect seedling growth,biomass and nitrogen con-tent accumulation in different organs. The total nitrogen and total phosphorus contents in different organs and biomass of C. migao all represented leaf> stem> root,and the contents increased as nitrogen supply enhanced. At different growth stages,different nitrogen concentrations had various effects on physiological and biochemical indexes of C. migao seed-lings. Under the treatment of N3,indexes such as seedling height(24.81 cm),ground diameter(0.3175 cm),chlorophyll content(3.3561 mg/g),soluble protein content(5.1799 mg/g),and soluble sugar content(24.4501 mg/g)indicated obvi-ous inhibition effects on C. migao seedling before August. At the same growing period,the physiological and biochemical indexes under N1 treatment were generally lower than those under the other three treatments. At the same time,soluble protein content(6.2965 mg/g),superoxide dismutase(SOD)activity(92.4222 U/gFW)and peroxidase(POD)activity (7086.111 ΔOD470/gFW)under different nitrogen concentrations reached maximum in August.ConclutionInadequate supply of nitrogen severely constrains the physiological activity of C. migao seedlings,while oversupply of nitrogen only inhibits the growth of C. migao seedlings before August,and the inhibition is gradually lifted and can promote seedling growth after August,a vigorous stage of physiological activities for C. migao.