不同氮水平条件下油茶苗养分积累及化学计量特征  

Nutrient accumulation and stoichiometric characteristics of Camellia oleifera seedlings under different nitrogen levels

作　　者：喻苏琴 李凤娇 胡冬南[1] 郭晓敏[1] 李科 裘利洪[1] YU Suqin;LI Fengjiao;HU Dongnan;GUO Xiaomin;LI Ke;QIU Lihong(College of Forestry,Jiangxi Agricultural University,Nanchang 330045,Jiangxi,China)

机构地区：[1]江西农业大学林学院,江西南昌330045

出　　处：《中南林业科技大学学报》2023年第4期1-9,共9页Journal of Central South University of Forestry & Technology

基　　金：国家重点研发计划项目(2018YFD1000603);国家自然科学基金项目(31760223)。

摘　　要：【目的】研究氮添加对油茶幼苗养分积累和主要大量营养元素含量、比值等计量特征的影响,为探究氮对油茶苗生长的影响机理及其与碳、磷等互作关系提供科学参考,同时可为油茶苗氮素养分管理提供理论依据。【方法】以油茶2年生实生苗为试验材料,设置0 mmol·L^(-1)(N0,CK)、5 mmol·L^(-1)(N1)、10 mmol·L^(-1)(N2)、15 mmol·L^(-1)(N3)、20 mmol·L^(-1)(N4)共5个氮浓度处理,开展盆栽试验。测定油茶苗各器官生物量和碳氮磷钾元素含量,计算养分累积量、养分利用效率和元素化学计量比。【结果】氮添加显著提升油茶体内N素含量,各器官N含量均在N3水平下达到峰值。随着氮水平的升高,根系C、P含量和叶片P含量呈下降趋势,叶片C和茎部C、P、K含量保持不变。中高浓度氮素(N3、N4)能促进油茶苗干物质和养分的积累,N4处理促进作用最大。氮浓度处理改变了养分的分配格局,随着氮水平的升高,根系养分占比下降,叶片养分比例升高。氮添加降低了N素利用效率,对P、K利用效率影响不大。随着氮水平的升高,各器官C∶N值减小,N∶P值增大。根据N∶P<10和>20的判断标准,油茶苗在N3和N4处理下(N∶P分别为10.86和13.81)不受N限制,即N浓度为15 mmol·L^(-1)以上时能满足油茶苗生长。相关分析结果表明,根、茎、叶N含量与全株N累积量和叶片N∶P极显著正相关,与N素利用效率和叶片C∶N极显著负相关,根和叶的N含量还与P、K累积量显著正相关。【结论】一定浓度的氮素可促进油茶苗干物质和养分的积累,15 mmol·L^(-1)以上能满足油茶苗生长,20 mmol·L^(-1)的促进作用最大。由于氮水平条件的不同而导致的油茶各器官氮含量的变化,不仅直接影响油茶氮素积累量和氮利用率,也会影响油茶对磷、钾的积累及元素的化学计量比。【Objective】The aim was to study the effects of nitrogen addition on nutrient accumulation as well as the content and ratio of major nutrient elements of Camellia oleifera seedlings,so as to provide a scientific reference for exploring the influencing mechanism of nitrogen on the growth of C.oleifera seedlings and its interaction with carbon and phosphorus,and provide a theoretical basis for the nitrogen nutrient management of C.oleifera seedlings.【Method】Taking the two-year-old C.oleifera seedlings as the experimental materials,five nitrogen concentrations:0 mmol·L^(-1)(N0,CK),5 mmol·L^(-1)(N1),10 mmol·L^(-1)(N2),15 mmol·L^(-1)(N3)and 20 mmol·L^(-1)(N4),were set to carry out pot experiments.The biomass and carbon,nitrogen,phosphorus and potassium content of each organ of the C.oleifera seedlings were measured,and the nutrient accumulation,nutrient utilization efficiency and element stoichiometry were calculated.【Result】Nitrogen addition significantly increased the N content of C.oleifera,and the N content in each organ reached the peak under the N3 treatment.With the increase in nitrogen level,the contents of root C and P as well as the leaf P content decreased,while leaf C content and stem C,P and K contents remained unchanged.Medium and high concentrations of nitrogen(N3,N4)could promote the dry matter and nutrient accumulation of C.oleifera seedlings,and the N4 treatment had the greatest promotion effect.Nitrogen treatment changed the nutrient distribution pattern.With the increase in nitrogen level,the proportion of root nutrients decreased,and the proportion of leaf nutrients increased.Nitrogen addition decreased N use efficiency,but it had little effect on the use efficiency of P and K.With the increase in nitrogen level,the C∶N value of each organ decreased,and the N∶P value increased.According to the judgment standard of N∶P<10 and N∶P>20,C.oleifera seedlings were not limited by N under N3 and N4 treatments(the N∶P ratio was 10.86 and 13.81,respectively),that is,when the N conce

关 键 词：氮 油茶幼苗 养分积累 化学计量比 

分 类 号：S718.5[农业科学—林学]