Changes in the delta13C values of trees during a tropical rainy season: some effects in addition to diffusion and carboxylation by Rubisco?
Changes in the delta13C values of trees during a tropical rainy season: some effects in addition to diffusion and carboxylation by Rubisco?
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热带雨季期间树木 delta13C 值的变化：除了 Rubisco 的扩散和羧化之外还有其他影响吗？
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
V. Terwilliger
中科院分区：
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作者：
V. Terwilliger
在帕纳马的整个雨季中，比较了开放和封闭树冠环境中落叶和万年青树叶的d13 C值。新出现的叶子有较高的d13 C值比老叶的所有幼苗和树木在所有日期采样。这显然不是由于水分利用效率的下降，因为叶片的发展，因为瞬时CI/CA显着高于新出现的比在同一树枝上的树木在该领域，以及在一个受控的，不变的环境中生长的幼苗展开叶。在不同的环境比较中，新出现的叶子中的d13 C值较高。例如，在雨季出现的叶子有较高的d13 C值比相应的成熟的叶子，出现在旱季和水是丰富的。因此，13 C的早期富集可能反映了碳的转移以启动新叶。此外，这种富集对小气候缺乏敏感性表明，它可能是Rubisco固碳后发生的过程的结果。随着叶片发育，d13 C值的其他变化也可能是由碳转运过程引起的。落叶Apeiba membranacea的叶片生物量的大部分后，叶片d13 C显着下降。在雨季结束时，万年青Cecropia insignis的d13 C值在开放的林冠中比在封闭的林冠中低。这些结果表明，d13 C值的树叶可以产生生态信息的碳在树木内的分配。
The d13C values of deciduous and evergreen tree leaves were compared in open and closed- canopy environments throughout a rainy season in Panamá. Newly emerging leaves had higher d13C values than older leaves of all seedlings and trees at all dates sampled. This was apparently not caused by a decline in water use efficiency as leaves develop because instantaneous ci/ca was significantly higher in newly emerging than in expanded leaves on the same twigs of trees in the field as well as on seedlings growing in a controlled, unchanging environment. Higher d13C values in newly emerging leaves occurred across diverse environmental comparisons. For example, leaves emerging during the rainy season had higher d13C values than corresponding mature leaves that had emerged both during the dry season and when water was abundant. The early enrichment in 13C may thus reflect the translocation of carbon to initiate a new leaf. Furthermore, the lack of sensitivity of this enrichment to a microclimate suggests that it might be the result of processes that occur after carbon fixation by Rubisco. Other changes in d13C values as leaves developed may also have resulted from carbon translocation processes. Foliar d13C decreased significantly after most of the leaf biomass of the deciduous Apeiba membranacea had developed. The d13C values of the evergreen Cecropia insignis were lower in the open canopy than in closed-canopy forests at the end of the rainy season. These findings suggest that the d13C values of leaves can yield ecological information about the allocation of carbon within trees.