樹葉温度の亜熱帯から北極への収束
Brent R Helliker1, Suzanna L Richter
1Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. helliker@sas.upenn.edu
Nature
|June 13, 2008
まとめ
木の葉の温度は,緯度を超えて驚くほど恒定であり,酸素同位体比 (デルタ: 18 O) を用いて気候の再構築のための仮定に挑戦しています. 植物生理学は,周囲の空気条件だけでなく,葉の温度にも大きく影響します.
科学分野:
- 植物生理学 植物生理学
- イソトープ地球化学 イソトープ地球化学
- 気候科学 気候科学
背景:
- セルロースの酸素同位体比 (デルタ ((18) O) は,通常,植物の炭素同化過程で過去の温度と湿度を推論するために使用されます.
- 重要な前提は,葉と周囲の空気条件は,光合成の間に同一であるということです.
研究 の 目的:
- セルロースデルタを用いて樹冠の葉の温度を測定する新しい方法を導入する.
- 葉の温度,空気の温度,および様々なバイオームの緯度間の関係を調査する.
主な方法:
- 39種の樹木のセルロースに含まれる酸素同位体比 (デルタ(18) O) の分析.
- 広い緯度グラデーション (亜熱帯から北極) にわたる葉の温度測定.
主要な成果:
- すべての研究された緯度で21.4 ± 2.2 °Cの一貫した葉の温度が観察されました.
- 葉の温度は,特に北緯度では,植物生理学的および形態学的適応により,空気温よりも大幅に高いことが判明しました.
- これは,葉の温度が環境空気の条件によってのみ決定されないことを示しています.
結論:
- イソトープベースの気候再構築のための葉と空気温度の等価性に関する仮定は,挑戦されています.
- 植物生理学的生態学は,同位体プロキシを用いた正確な気候史の解釈に不可欠である.
- これらの発見は,気候が一般の葉の経済特性に及ぼす影響が限られていることを説明するかもしれない.
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