The Effect Of Nitrogen And Phosphorus On Growth And Physiological Characteristics Of Cinnamomum Migao Seedling

Migao?Cinnamomum migao H. W. Li? belongs to Lauraceae Cinnamomum evergreen trees, mainly distributed in GuiZhou, YunNan, Guang Xi Province. The mature fruit is one of the ten herbal medicines and it is developed as the ethnic Chinese herbal medicines meaningful in recent years in Guizhou Province. In this paper, the experiment was conducted in green house, the half-year-old Migao seedling were cultured in sand and supplied with different levels of nitrogen and phosphorus.The growth, physiology and biochemistry index, photosynthesis characteristics of Migao seedlings on the condition of different levels of nitrogen and phosphorus supply were measured. It revealed the needs of nitrogen and phosphorus and fertilization timing of Migao seedlings, provided a theoretical basis and technical methods to plant nursery and plantation management about Migao seedings. The results of the study were summarized as follows:?1?The rectangular hyperbola modified model is the optimal model that fitted Migao light response and CO₂ response curve. According to the model fitted value,under the treatment of N₃, the light saturation point and light compensation point of Migao were 1722.04 and 13.77 ?mol·m-2·s-1,CO₂ saturation point and CO₂ compensation point were 1075.07 and 37.09 ?mol·mol–1;the treatment of N1,the light saturation point and light compensation point of Migao were 999.67 and 32.13?mol·m-2·s-1,CO₂ saturation point and CO₂ compensation point were 797.74 and52.13 ?mol·mol–1.Under the treatment of P3, the light saturation point and light compensation point of Migao were 1600.42 and 13.64 ?mol·m-2·s-1, CO₂ saturation point and CO₂ compensation point were 1546.14 and 44.06 ?mol·mol–1;the treatment of P1, the light saturation point and light compensation point of Migao were 1483.56 and 29.50 ?mol·m-2·s-1, CO₂ saturation point and CO₂ compensation point were842.58 and 44.32 ?mol·mol–1.The value show that fertilized nitrogen and phosphorus can improve Migao photosynthetic capacity, but the influence of nitrogen is greater than phosphorus.?2?Different levels of nitrogen and phosphorus could significantly affect the growth, biomass accumulation and the allocation of nitrogen and phosphorus in different organ?P<0.05?. Under the treatment of nitrogen,it will restrain the growth of Migao if fertilizing the nitrogen beyond 16 mmol-1 at the early seedling growth.Under the treatment of phosphorus: compared with the Migao seeding which under the treatment of normal phosphorus grow very well throughout the growth season, so fertilizing the phosphorus beyond or below the normal levels both are harmful to seedings grow.The total nitrogen and phosphorus in every organ and biomass of Migao all represented leaf> stem> root,it convinced that the leaves are the main organ which stored biomass and the nutrition of nitrogen and phosphorus and were higher with the nitrogen and phosphorus supply increasing.?3? At different growth stages, Nitrogen and Phosphorus all have different effects on the physiological and biochemical indexes of Migao seedings?P<0.05?. Under the treatment of nitrogen, high density levels of nitrogen?16 mmol-1? caused negative influence on chlorophyll, soluble protein, soluble sugar, MDA content, SOD activity and POD activity of Migao seedings. But with the days increased, the negative effects gradually weakened.Under the treatment of phosphorus,high density levels of phosphorus?2 mmol-1? caused negative influence only at the early seedling growth. At the same growing season,under the treatment of low nitrogen,the physiological and biochemical indicators in general lower than the other three groups, indicating that inadequate supply of nitrogen severely constrained the physiologically active of Migao seedlings,and physiological and biochemical indexes were no significant overall treatment phosphorus.At the same time,some physiological indexes reached a maximum in August, indicating that August is the strongly physiological activities of Migao, with the growth of seedlings,the amount of nitrogen and phosphorus content can be increased slowly.