The oxygen isotope enrichment of leaf-exported assimilates--does it always reflect lamina leaf water enrichment?
The oxygen isotope enrichment of leaf-exported assimilates--does it always reflect lamina leaf water enrichment?
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DOI：
10.1111/nph.12359
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发表时间：
2013-10
期刊：
影响因子：
--
通讯作者：
Treydte K
中科院分区：
文献类型：
--
作者：
Gessler A;Brandes E;Keitel C;Boda S;Kayler ZE;Granier A;Barbour M;Farquhar GD;Treydte K
植物有机质（尤其是树木年轮档案中的木材和纤维素）的氧稳定同位素组成在植物-气候相互作用研究中具有重要价值，但有关同位素信号从叶片到异养组织的传递的信息还很缺乏。本文研究了五种不同生活型树种叶水的氧同位素组成及其在源水之上的富集。我们跟踪了同位素信号向叶水溶性OM和进一步向韧皮部运输OM的转移。观察到的叶水蒸发富集是一致的，从机械模型，考虑到非稳态条件下的预测值。虽然叶水溶性OM表现出预期的18 O富集在所有物种中，韧皮部糖富集比预期的少，从叶水富集在苏格兰松（樟子松），欧洲落叶松（落叶落叶松）和高山灰（桉树delegatensis）。韧皮部装载和运输过程中与非富集水的氧原子交换，以及树皮光合作用同化物的重要贡献，可以解释这些韧皮部18 O富集模式。我们的研究结果表明，种特异性解耦合之间的叶水和OM氧同位素信号，这是很重要的树轮数据的解释。
The oxygen stable isotope composition of plant organic matter (OM) (particularly of wood and cellulose in the tree ring archive) is valuable in studies of plant–climate interaction, but there is a lack of information on the transfer of the isotope signal from the leaf to heterotrophic tissues. We studied the oxygen isotopic composition and its enrichment above source water of leaf water over diel courses in five tree species covering a broad range of life forms. We tracked the transfer of the isotopic signal to leaf water-soluble OM and further to phloem-transported OM. Observed leaf water evaporative enrichment was consistent with values predicted from mechanistic models taking into account nonsteady-state conditions. While leaf water-soluble OM showed the expected 18O enrichment in all species, phloem sugars were less enriched than expected from leaf water enrichment in Scots pine (Pinus sylvestris), European larch (Larix decidua) and Alpine ash (Eucalyptus delegatensis). Oxygen atom exchange with nonenriched water during phloem loading and transport, as well as a significant contribution of assimilates from bark photosynthesis, can explain these phloem 18O enrichment patterns. Our results indicate species-specific uncoupling between the leaf water and the OM oxygen isotope signal, which is important for the interpretation of tree ring data.
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影响因子：
7.4
作者：
Barbour, MM;Schurr, U;Farquhar, GD
通讯作者：
Farquhar, GD
影响因子：
6.2
作者：
Erxleben, Anika;Gessler, Arthur;Reski, Ralf
通讯作者：
Reski, Ralf
影响因子：
11.6
作者：
Brandes, Elke;Kodama, Naomi;Gessler, Arthur
通讯作者：
Gessler, Arthur
影响因子：
7.3
作者：
FLANAGAN, LB;MARSHALL, JD;EHLERINGER, JR
通讯作者：
EHLERINGER, JR
影响因子：
7.3
作者：
Barnard, Romain L.;Salmon, Yann;Buchmann, Nina
通讯作者：
Buchmann, Nina