Insights into source/sink controls on wood formation and photosynthesis from a stem chilling experiment in mature red maple
Insights into source/sink controls on wood formation and photosynthesis from a stem chilling experiment in mature red maple
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通过成熟红枫的茎冷却实验深入了解木材形成和光合作用的源/库控制
DOI：
10.1111/nph.18421
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发表时间：
2022
期刊：
影响因子：
9.4
通讯作者：
Richardson, Andrew D.
中科院分区：
文献类型：
--
作者：
Rademacher, Tim;Fonti, Patrick;LeMoine, James M.;Fonti, Marina V.;Bowles, Francis;Chen, Yizhao;Eckes‐Shephard, Annemarie H.;Friend, Andrew D.;Richardson, Andrew D.
究竟是源还是汇控制着木材的生长，目前还存在争议，缺乏来自自然环境中成熟树木的证据。在这里，我们改变了成熟红枫茎的碳供应速率（Acer rubrum）在生长季节内通过限制韧皮部运输利用茎冷却;从而增加碳供应到限制之上并减少碳供应到限制之下，冷冻成功地改变了韧皮部中的非结构碳（NSC）浓度，而对茎和根中的大量NSC没有可检测到的影响。年轮宽度对碳供应的局部变化反应强烈，沿着冷藏树的树干差异高达7倍;然而，由于木材生长的局部变化较大，在高碳供应下，结构碳的同时变化是不确定的。在低温诱导的瓶颈之上，我们还观察到较高的叶片NSC浓度，降低的光合能力，以及较早的叶片着色和fall.Our结果表明，形成层库受碳供应的影响，但树内反馈可以下调源活性，当碳供应超过需求时。这种反馈只在成熟的树木中被假设过。因此，这些发现构成了理解源-库动态的重要进展，表明成熟的红枫在生长季节早期接近源和库限制。
Whether sources or sinks control wood growth remains debated with a paucity of evidence from mature trees in natural settings.Here, we altered carbon supply rate in stems of mature red maples (Acer rubrum) within the growing season by restricting phloem transport using stem chilling; thereby increasing carbon supply above and decreasing carbon supply below the restrictions, respectively.Chilling successfully altered nonstructural carbon (NSC) concentrations in the phloem without detectable repercussions on bulk NSC in stems and roots. Ring width responded strongly to local variations in carbon supply with up to seven‐fold differences along the stem of chilled trees; however, concurrent changes in the structural carbon were inconclusive at high carbon supply due to large local variability of wood growth. Above chilling‐induced bottlenecks, we also observed higher leaf NSC concentrations, reduced photosynthetic capacity, and earlier leaf coloration and fall.Our results indicate that the cambial sink is affected by carbon supply, but within‐tree feedbacks can downregulate source activity, when carbon supply exceeds demand. Such feedbacks have only been hypothesized in mature trees. Consequently, these findings constitute an important advance in understanding source–sink dynamics, suggesting that mature red maples operate close to both source‐ and sink‐limitation in the early growing season.