Nitrogen and carbon source-sink relationships in trees at the Himalayan treelines compared with lower elevations

No single hypothesis or theory has been widely accepted for explaining the functional mechanism of global alpine/arctic treeline formation. The present study tested whether the alpine treeline is determined by (1) the needle nitrogen content associated with photosynthesis (carbon gain); (2) a suffic...

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Bibliographic Details
Published in:Plant, Cell & Environment
Main Authors: Li, Mai-He, Xiao, Wen-Fa, Shi, Peili, Wang, San-Gen, Zhong, Yong-De, Liu, Xing-Liang, Wang, Xiao-Dan, Cai, Xiao-Hu, Shi, Zuo-Min
Format: Article in Journal/Newspaper
Language:English
Published: 2008
Subjects:
Altitudinal Limit
Carbon Limitation
C-balance
C-n Ratio
Growth Limitation
Non-structural Carbohydrates
Starch
Sugars
Science & Technology
Life Sciences & Biomedicine
Plant Sciences
PINUS-CEMBRA TREES
GROWTH-LIMITATION
SWISS TREELINE
TEMPERATURE
CO2
RESPONSES
SEEDLINGS
PHOTOSYNTHESIS
CARBOHYDRATE
ACCLIMATION
Arctic
The Needle
Online Access:http://ir.imde.ac.cn/handle/131551/10537
https://doi.org/10.1111/j.1365-3040.2008.01848.x
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Summary:No single hypothesis or theory has been widely accepted for explaining the functional mechanism of global alpine/arctic treeline formation. The present study tested whether the alpine treeline is determined by (1) the needle nitrogen content associated with photosynthesis (carbon gain); (2) a sufficient source-sink ratio of carbon; or (3) a sufficient C-N ratio. Nitrogen does not limit the growth and development of trees studied at the Himalayan treelines. Levels of non-structural carbohydrates (NSC) in trees were species-specific and site-dependent; therefore, the treeline cases studied did not show consistent evidence of source/carbon limitation or sink/growth limitation in treeline trees. However, results of the combined three treelines showed that the treeline trees may suffer from a winter carbon shortage. The source capacity and the sink capacity of a tree influence its tissue NSC concentrations and the carbon balance; therefore, we suggest that the persistence and development of treeline trees in a harsh alpine environment may require a minimum level of the total NSC concentration, a sufficiently high sugar:starch ratio, and a balanced carbon source-sink relationship.

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