摘要
Abstract
Nitrogen is involved in a variety of physiological metabolic processes of plants and is the most important nutrient element to regulate plant growth and development.As an important timber forest and economic forest afforestation tree species in subtropical regions,this study aims to explore the application potential of nitrogen in the cultivation of strong seedlings and the scientific manage-ment of plantations in Cinnamomum cam phora.In this experiment,C.camphora seedlings were used as experimental materials to analyze the changes of seedling leaf growth and photosynthetic character-istics under different proportions of nitrate nitrogen(NO3--N)and ammonium nitrogen(NH4+-N).The results showed that nitrogen forms significantly affected the growth of C.camphora seedlings.Among them,the seedling height,ground diameter and biomass were the largest under the equal pro-portion(5∶5)of ammonium nitrate nitrogen treatment,while the root-shoot ratio was the largest under the treatment of 3∶7 ammonium nitrate ratio(NO3--N∶NH4+-N).Compared with the con-trol without nitrogen application,there was no significant change in seedling height,ground diameter and root-shoot ratio under pure nitrate nitrogen treatment,but the biomass decreased,while the ground diameter and root-shoot ratio under pure ammonium nitrogen treatment did not change sig-nificantly,but the seedling height and biomass increased.The ratio of different forms of nitrogen was different,and the photosynthetic parameters of seedling leaves were also different.On the whole,the net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs),intercellular car-bon dioxide concentration(Ci),chlorophyll content and stomatal density of leaves were the highest under the treatment of equal proportion of ammonium nitrate nitrogen.Linear correlation analysis showed that there was no significant correlation between Pn and chlorophyll content(P＞0.05,R2=0.65),but there was a significant positive correlation between Pn and stomatal density(P＜0.05,R2=0.88).The study suggests that C.cam phora is a kind of ammonium nitrogen tree species,but the compound equal proportion of nitrate and ammonium nitrogen fertilizer has a significant effect on the growth and photosynthetic capacity of C.camphora.关键词
樟树/氮素形态/精准施肥/生长/光合能力Key words
Cinnamomum camphora/Nitrogen formn/Precision fertilization/Growth/Photosynthetic capacity分类
农业科技
