Seasonal changes of &dgr;D and &dgr;18O in tree-ring cellulose of Quercus crispula suggest a change in post-photosynthetic processes during earlywood growth
Seasonal changes of &dgr;D and &dgr;18O in tree-ring cellulose of Quercus crispula suggest a change in post-photosynthetic processes during earlywood growth
复制标题
季节变化
作者：
E. Nabeshima;T. Nakatsuka;A. Kagawa;T. Hiura;R. Funada
叶片光合和光合后过程调节年轮纤维素同位素比值。光合作用后的过程，如储存的淀粉在早春的再动员，是很重要的了解木质部形成的机制，在树干，然而，解开的同位素比率信号的光合作用和光合作用后的过程印记在树木年轮是困难的。部分碳结合的氢和氧原子在光合作用后过程中与介质水交换。以2种不同生境的皱皮栎（Quercus crispula Blume）为材料，通过测定其年轮纤维素的δD和δ 18 O值，研究了皱皮栎与介质水交换速率（f值）的季节变化及其与光合后过程的关系。理论上，当f值一定时，δD与δ 18 O之间会因气象因素而呈正相关，而f值的变化会因碳结合氢和氧与介质水的交换而使δD与δ 18 O之间产生差异，相关性较弱。δD值从早材到晚材急剧下降，而δ 18 O值则先上升到一个峰值，然后向晚材下降。估计的季节f值在早材开始时较高，并向晚材下降。与f值变化相关的光合后过程是早春光合产物不足导致的纤维素合成过程中淀粉和丙糖循环的再动员。虽然没有测定相关的生理参数，但我们对栓皮栎树轮纤维素δD和δ18O的季节变化进行了研究。crispula的结果表明，双同位素（δD和δ18O）方法可用于揭示季节性木质部形成的资源分配机制。
Leaf photosynthetic and post-photosynthetic processes modulate the isotope ratios of tree-ring cellulose. Post-photosynthetic processes, such as the remobilization of stored starch in early spring, are important to understanding the mechanisms of xylem formation in tree stems; however, untangling the isotope ratio signals of photosynthetic and post-photosynthetic processes imprinted on tree rings is difficult. Portions of carbon-bound hydrogen and oxygen atoms are exchanged with medium water during post-photosynthetic processes. We investigated the δD and δ18O values of tree-ring cellulose using Quercus crispula Blume trees in two different habitats to evaluate seasonal changes in the exchange rate (f-value) of hydrogen or oxygen with medium water, and examined the associations of the post-photosynthetic processes. Theoretically, if the f-value is constant, δD and δ18O would be positively correlated due to meteorological factors, while variation in the f-value will create a discrepancy and weak correlation between δD and δ18O due to the exchange of carbon-bound hydrogen and oxygen with medium water. The values of δD decreased drastically from earlywood to latewood, while those of δ18O increased to a peak and then decreased toward the latewood. The estimated seasonal f-value was high at the beginning of earlywood and decreased toward the latewood. The post-photosynthetic processes associated with changes in the f-value were the remobilization of stored starch and triose cycling during cellulose synthesis because of the shortage of photo-assimilates in early spring. Although we did not evaluate relevant physiological parameters, the seasonal pattern of δD and δ18O in tree-ring cellulose of Q. crispula was clear, suggesting that the dual isotope (δD and δ18O) approach can be used to reveal the resource allocation mechanisms underlying seasonal xylem formation.
影响因子：
4
作者：
Offermann, Christine;Pedro Ferrio, Juan;Gessler, Arthur
通讯作者：
Gessler, Arthur
DOI：
10.1111/nph.12359
发表时间：
2013-10
期刊：
The New phytologist
影响因子：
--
作者：
Gessler A;Brandes E;Keitel C;Boda S;Kayler ZE;Granier A;Barbour M;Farquhar GD;Treydte K
通讯作者：
Treydte K