不同氮素水平对米槁幼苗生长和生理特性的影响

目的]探讨不同氮素水平对米槁幼苗生长和生理特性的影响,为米槁幼苗栽培和管理提供参考依据.方法]采用温室砂培技术培养米槁幼苗,设1.0 mmol/L(N1处理)、4.0 mmol/L(N2处理)、8.0 mmol/L(CK)和16.0 mmol/L(N3处理)4个氮素水平处理,系统测定不同氮素水平下米槁幼苗的形态和生理生化指标.结果]不同氮素水平处理均能明显影响米槁幼苗生长、生物量及各器官氮含量积累.米槁幼苗的生物量及各器官的全氮和全磷含量排序均表现为叶>茎>根,且随施氮素水平的提高而增加.在不同生长期,不同氮素水平处理对米槁生理生化指标均产生不同的影响,8月以前,N3处理对米槁苗高(24.81 cm)、地径(0.3175 cm)、叶绿素含量(3.3561 mg/g)、可溶性蛋白含量(5.1799 mg/g)和可溶性糖含量(24.4501 mg/g)等指标均产生明显的抑制作用;同一生长期内,N1处理下各生理生化指标总体上均低于其他3个处理.同时,不同氮素水平处理米槁的可溶性蛋白含量(6.2965 mg/g)、超氧化物歧化酶(SOD)活性(92.4222 U/gFW)和过氧化物酶(POD)活性(7086.111ΔOD470/gFW)在8月达最大值.结论]米槁幼苗期氮素供给不足会严重制约其生理活性,在8月以前氮素供给过量会对幼苗生长造成胁迫,在8月以后胁迫逐渐解除并促进米槁幼苗生长,即8月是米槁生理活动的旺盛期.

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

Objective]Effects 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.Method]C. 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.Result]The 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.Conclution]Inadequate 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.