Key message

Flow within internal secretory systems derived from autolyzing epithelia in kino-producing angiosperms may have lower metabolic energy costs. This presents physiological advantages and possibly constitutes an evolutionary step of these species compared to resin flow in conifers in using internal secretory systems in plant defence mechanisms.

Abstract

Kino is a plant exudate, rich in polyphenols, produced by several angiosperms in reaction to injury of the cambium. It flows out of kino veins, which compose an anatomically distinct continuous system of tangentially anastomosing canals produced by the cambium upon damage, encircling plant stems and branches. Kino is loaded into the vein lumen by autolysis of a cambiform epithelium lined by suberized cells that separate kino veins from the surrounding axial parenchyma. A model describing kino flow is presented to investigate how vein distribution and structure, as well as the loading, solidification, and viscosity of kino affect flow. Considering vein anatomy, viscosity, and a time-dependent loading of kino, the unsteady Stokes equation was applied. Qualitatively, kino flow is similar to resin flow observed on conifers. There is an increase in flow towards the vein open end, with both pressure and flow depending on the vein dimensions, properties, and loading of kino. However, kino veins present a much smaller specific resistance to flow compared to resin ducts. Also, unlike resin loading in conifers, the loading of kino is not pressure-driven. The pressure and pressure gradient required to drive an equally fast flow are smaller than what is observed on the resin ducts of conifers. These results agree with previous observations on some angiosperms and suggest that flow within internal secretory systems derived from autolysing epithelia may have lower metabolic energy costs; thus presenting physiological advantages and possibly constituting an evolutionary step of angiosperms in using internal secretory systems in plant defence mechanisms compared to resin flow in conifers. Understanding of how these physiological and morphological parameters affect kino flow might be useful for selecting species and developing more sustainable and economically viable methods of tapping gum and gum resin in angiosperms.

中文翻译：

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被子植物中的全息分泌和肌动蛋白流：它们在植物防御机制中的作用和生理优势

关键信息

内部分泌系统内部的流量源自产生动感的被子植物中的自溶上皮，可能具有较低的代谢能成本。与在植物防御机制中使用内部分泌系统的针叶树中的树脂流相比，这具有生理优势，并且可能构成了这些物种的进化步骤。

抽象

奇诺（Kino）是一种植物分泌液，富含多酚，是由几种被子植物对形成层伤害的反应产生的。它从奇诺静脉流出，该脉络构成了由形成层在受到破坏时切向吻合的，解剖学上截然不同的连续系统，环绕着植物的茎和分支。角蛋白通过将由角膜上皮细胞覆盖的干细胞上皮自溶而加载到静脉腔中，这些细胞将角膜静脉与周围的轴向薄壁组织分开。提出了描述奇诺流动的模型，以研究静脉的分布和结构以及奇诺的载荷，凝固和粘度如何影响流动。考虑到静脉解剖结构，粘度和随时间变化的肌腱负荷，应用了不稳定Stokes方程。定性地，基诺流动类似于在针叶树上观察到的树脂流动。流向静脉开口端的流量增加，压力和流量取决于静脉的尺寸，性质和肌动蛋白的负荷。但是，与树脂导管相比，奇诺静脉的流动阻力小得多。另外，与针叶树中的树脂负载不同，基诺的负载不是压力驱动的。驱动同等快速流动所需的压力和压力梯度小于在针叶树的树脂导管上观察到的压力和压力梯度。这些结果与以前在某些被子植物上的观察结果一致，并表明内部分泌系统中源自自溶性上皮的流动可能具有较低的代谢能量消耗。因此，与针叶树中的树脂流相比，在植物防御机制中使用内部分泌系统提供了生理优势，并可能构成被子植物的进化步骤。了解这些生理和形态参数如何影响肌动蛋白流动可能有助于选择物种，并开发出更可持续和经济上可行的在被子植物中攻取口香糖和口香糖树脂的方法。