植物生态学报 ›› 2013, Vol. 37 ›› Issue (7): 591-600.DOI: 10.3724/SP.J.1258.2013.00061

所属专题: 稳定同位素生态学

• 研究论文 •    下一篇

四川巴郎山齿果酸模叶片氮素及其分配的海拔响应

冯秋红1,2,程瑞梅1,史作民1,*(),刘世荣1,王卫霞1,刘兴良2,何飞2   

  1. 1中国林业科学研究院森林生态环境与保护研究所国家林业局森林生态环境重点实验室, 北京 100091
    2四川省林业科学研究院, 成都 610081
  • 收稿日期:2012-12-28 接受日期:2013-06-04 出版日期:2013-12-28 发布日期:2013-07-05
  • 通讯作者: 史作民
  • 基金资助:
    国家自然科学基金面上项目(307717-18);中国林科院中级公益性科研院所基本科研业务费专项资金项目(CAFRIF200717);林业公益性行业科研专项(200804001)

Response of Rumex dentatus foliar nitrogen and its allocation to altitudinal gradients along Balang Mountain, Sichuan, China

FENG Qiu-Hong1,2,CHENG Rui-Mei1,SHI Zuo-Min1,*(),LIU Shi-Rong1,WANG Wei-Xia1,LIU Xing-Liang2,HE Fei2   

  1. 1Key Laboratory on Forest Ecology and Environmental Sciences of State Forestry Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
    2Sichuan Academy of Forestry, Chengdu 610081, China
  • Received:2012-12-28 Accepted:2013-06-04 Online:2013-12-28 Published:2013-07-05
  • Contact: SHI Zuo-Min

摘要:

在卧龙自然保护区, 按海拔梯度选择了齿果酸模(Rumex dentatus)的4个分布地点(2350、2700、3150和3530 m), 对各研究地点的齿果酸模进行了叶片光合、扩散导度、叶片碳稳定同位素组成(δ13C)、氮素含量、光合氮利用效率(PNUE)、比叶面积(SLA))等参数的测量, 以期揭示该植物叶片氮素、氮素分配情况及其他生理生态参数随海拔的响应趋势, 进而明确氮素及其分配在齿果酸模响应和适应海拔梯度环境的生物学过程中的作用。结果表明: 随着海拔的升高, 齿果酸模的叶片单位面积氮含量(Narea)随之增加, 进而光合能力随之增加。随着海拔升高而增加的扩散导度也在一定程度上促进了这一趋势, 这可能是落叶草本植物对于高海拔低温所导致的叶寿命缩短的适应结果。沿着海拔梯度, 植物叶片氮素和扩散导度均通过羧化位点与外界CO2分压比(Pc/Pa)而间接影响叶片δ13C值, 且相比之下, 以氮素为基础的羧化能力对于Pc/Pa的作用更大些, 进而导致齿果酸模叶片δ13C随海拔增加; 随着海拔的升高, 齿果酸模叶片将更多的氮素用于防御性结构组织的建设, 这也是SLAPNUE降低的主要原因; 在光合系统内部, 随着海拔的升高, 植物光合组织增加了用于捕光系统氮素的比例, 使得植物可以更好地利用随海拔升高而增强的光照资源, 进而促进了光合能力的增加。可见, 氮素及其在叶片各系统间(尤其是在光合系统与非光合系统间)的分配方式是齿果酸模适应和响应海拔梯度环境的关键。

关键词: 海拔响应, 叶片氮素分配, 齿果酸模, 卧龙自然保护区

Abstract:

Aims As a key element in plant tissue, nitrogen plays an important role in the growth and development of plants. Our objective is to determine (1) how both leaf nitrogen and its allocation between photosynthetic and non-photosynthetic systems have responded to an altitudinal gradient and (2) what role their response has played in the adaptation of Rumex dentatus to its changed environment along the altitudinal gradient.
Methods We measured foliar parameters of photosynthesis, diffusional conductance to CO2, stable carbon isotope ratio (δ13C), nitrogen content and specific leaf area (SLA) of the forb R. dentatus in four sites with different altitudes (2350, 2700, 3150 and 3530 m) in the Wolong Reserve. One-way ANOVA was used to find the differences for all parameters among R. dentatus plants from different altitudes, and standardized major axis (SMA) was used to determine the relationships among some main parameters.
Important findings Leaf nitrogen content per area (Narea) increased as maximum photosynthetic capacity (Amax) increased with altitude in R. dentatus. Increased diffusional conductance also had a positive effect on increased photosynthetic capacity with altitude. These may be the result of adaptation of plants to a shortened leaf lifespan caused by low temperature at high altitude. Along with the altitudinal gradient, nitrogen and diffusional conductance of R. dentatus have an indirect effect on foliar δ13C through acting on the ratio of chloroplast partial pressure of CO2 to ambient CO2 partial pressure (Pc/Pa). Compared with diffusional conductance, nitrogen (or carboxylation capacity based on nitrogen) played a more important role in the process, in order to increase foliar δ13C with altitude. Rumex dentatus allocated more nitrogen to build defensive structural tissue with increased altitude. This is why SLA and photosynthetic nitrogen use efficiency (PNUE) decreased with altitude. In the photosynthetic system, more nitrogen was allocated to light-harvesting components in order that enhanced light resource was used preferably by R. dentatus, and then photosynthetic capacity was increased with altitude. Nitrogen and its allocation among systems (especially between photosynthetic and non-photosynthetic systems) are the keys to the adaptation and the response of R. dentatus to the gradient in altitude.

Key words: altitudinal response, nitrogen allocation in leaf, Rumex dentatus, Wolong Reserve