The oxygen supply to thermogenic flowers
The oxygen supply to thermogenic flowers
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产热花的氧气供应
DOI：
10.1111/pce.12454
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Philip D.G. Matthews & Stergios Arg. Pirintsos
中科院分区：
文献类型：
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作者：
Roger S. Seymour;Kikukatsu Ito;Yui Umekawa;Philip D.G. Matthews & Stergios Arg. Pirintsos
产热花通过强烈的呼吸作用产生热量，某些物种的氧气消耗率 (Ṁo2) 可能超过植物和大多数动物的所有其他组织。通过将完整的花朵暴露于一定范围的 O2 压力 (Po2) 并测量 o2，我们证明最高呼吸速率超过了 O2 扩散途径的能力，并且在大气中扩散受到限制。 Arum concinnatum 花序上的雄花具有已知最高的质量特异性Ṁo2，并且扩散受到严重限制。仅当 Ṁo2 最大时，日本臭甘蓝的完整花序在空气中的扩散才受到限制，但在较低水平时则不然。神圣莲花的真花 Nelumbo nucifera 和 Arum concinnatum 的附录在空气中的扩散永远不受限制。Ṁo2-Po2 曲线通过“调节指数”（一种测量 Ṁo2 对环境 Po2 依赖性的新工具）以及传统的“临界 Po2”进行定量评估。该研究还包括用 O2 敏感光纤测量产热组织内的 Po2，并揭示扩散途径很复杂，O2 不仅可以从组织表面提供，还可以从花梗的髓部提供。
Thermogenic flowers produce heat by intense respiration, and the rates of O2consumption (Ṁo2) in some species can exceed those of all other tissues of plants and most animals. By exposing intact flowers to a range of O2pressures (Po2) and measuringṀo2, we demonstrate that the highest respiration rates exceed the capacity of the O2diffusive pathway and become diffusion limited in atmospheric air. The male florets on the inflorescence ofArum concinnatumhave the highest known mass‐specificṀo2and can be severely diffusion limited. Intact spadices of Japanese skunk cabbageSymplocarpus renifoliusare diffusion limited in air only whenṀo2is maximal, but not at lower levels. True flowers of the sacred lotusNelumbo nuciferaand the appendix ofArum concinnatumare never diffusion limited in air.Ṁo2–Po2curves are evaluated quantitatively with the ‘Regulation Index’, a new tool to measure dependence ofṀo2on ambientPo2, as well as the conventional ‘CriticalPo2’. The study also includes measurements ofPo2within thermogenic tissues with O2‐sensitive fibre optics, and reveals that the diffusion pathway is complicated and that O2can be provided not only from the surface of the tissues but also from the pith of the flower's peduncle.