摘要
在根序水平上,细根具有高度形态和功能异质性,进行不同根序细根形态与养分特征的研究,对认识根系内部异质性具有重要意义。在西北干旱和半干旱区以典型荒漠植物红砂(Reaumuria soongorica)和白刺(Nitraria tangutorum)为研究对象,采用挖掘法收集根序完整细根,按照Pregitzer根系分级法对其分级,用细根分析软件(WinRHIZO)对细根形态参数进行测定,同时对各序级根C、N含量进行测定。结果发现:随着序级的升高,2种荒漠植物细根直径、根长均增加,而比根长则降低。随根序的升高,2种荒漠植物C含量和C/N比逐渐增加,而N含量逐渐降低,1级根C、N含量与2、3级根之间差异显著。根直径和根长与C含量及C/N呈显著或极显著正相关,而与N含量呈显著负相关,而比根长刚好相反。综上所述,2种典型荒漠植物形态的变化与功能相适应,支持短命根模式假说,末端细根的形态、结构决定其功能是吸收养分和水,而高级根的形态、结构决定其功能是运输和贮存养分。
Fine roots are highly heterogeneous in structure and function at the level of root orders. The study of fine roots morphology and nutrient content in different branch root orders is important to understand the variation pattern of fine root morphology and chemical composition and know internal heterogeneity of root. Reaumuria soongorica and Nitraria tangutorum are dominant species of the arid region of Northwest China. A field experiment was conducted to understand architecture and morphology of fine root systems of two species. Intact fine root segments of two desert plants were collected by excavation. Individual roots were dissected according to the branching order,starting from the distal end of the root system that was numbered as the first order and then increasing sequentially with each branch from the first order to higher order roots. Root length and diameter of different root orders were analyzed by Win-RHIZO system. The contents of C and N in a given order were determined using the Walkley-Black wet combustion and the semimicro-Kjeldahl methods,respectively. The results showed that with increasing root order,root diameter and root length increased and specific root length（SRL） decreased. C concentration and C/N ratio increased,but N concentrations decreased from low to high root order of fine root for two type of desert species. There were significant differences in C and N concentrations between first order and second and third order.There were significantly or extremely significantly positive correlation between root diameter and SRL and the contents of C and C/N ratio,which were significant negative correlation with the contents of N,and then SRL were opposite. Fine-root functions might be closely related to their morphology,these responses were supported by the concept of ephemeral root modules. Lower-order roots（First-order roots） represented absorptive roots,and higher-order roots（second and third-order roots） might have limited uptake capacity and function in transportation and storage.
出处
《草地学报》
CAS
CSCD
北大核心
2017年第5期1014-1019,共6页
Acta Agrestia Sinica
基金
国家自然科学基金(31560135
41361100
31360205
41461044)
甘肃省科技支撑项目(1604FKCA088)
甘肃农业大学青年研究生指导教师扶持基金(GAU-QNDS-201605)资助
关键词
细根
序级
细根结构
红砂
白刺
Fine root
Root order
Fine root architecture
Reaumuria soongorica
Nitraria tangutorum
