Factors affecting water availability for high Arctic lichens.
Factors affecting water availability for high Arctic lichens.
复制标题
影响高北极地衣可用水的因素。
DOI：
10.1007/s00300-016-2010-2
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发表时间：
2017
期刊：
影响因子：
1.7
通讯作者：
Kanda H.
中科院分区：
文献类型：
--
作者：
Inoue T.;Kudoh S.;Uchida M.;Tanabe Y.;Inoue M.;Kanda H.
地衣共生是一种成功的营养策略，可推动北极高海拔生态系统中地衣的分布。然而，真菌伙伴（真菌生物体）对光合伙伴（光生物体）的水可用性及其生存必要性的原位影响仍不清楚。我们通过对无雪季节斯瓦尔巴群岛新奥勒松附近（北纬 79°）高地北极地区的基质和叶状体形态的观测和实验分析，研究了造成高地北极地衣组合水分可用性差异的因素。我们使用了在五种基质类型上发现的五种地衣：苔藓枯落物、维管植物枯落物、混合枯落物、生物土壤结皮（BSC）和砾石。 BSC 的含水量明显高于其他基质；尽管其表面蒸发量较高，但 BSC 吸收了更多的地下水。此外，BSC 的结构比我们研究中的其他四种基质具有更大的保水性，为地衣提供了最潮湿的环境。事实上，主要分布在 BSC 上的结壳地衣 Ochrolechia frigida 60% 的表面积与基质接触。相比之下，四种果状地衣的表面积比 Och 冰霜更大，大约 90% 暴露在空气中。初始吸收和蒸发速率随着菌体表面积的增大而增加，这表明光生物体的水可用性受到形态特征和底物水性质的强烈影响，这两者都取决于真菌生物体。我们得出的结论是，地衣对形态和基质表现出偏好，以促进高北极地区水资源有限的冰川前陆的自养营养。
Lichen symbiosis is a successful nutritional strategy that drives lichen distributions in high Arctic ecosystems. However, the in situ effects of fungal partners (mycobionts) on water availability for the photosynthetic partners (photobionts) and their necessity for survival remain unclear. We investigated the factors creating differences in water availability in high Arctic lichen assemblages using observational and experimental analyses of substrates and thallus morphology in the high Arctic, near Ny-Ålesund, Svalbard (79°N) during the snow-free season. We used five lichen species found on five substrate types: moss litter, vascular plant litter, mixed litter, biological soil crust (BSC) and gravel. BSC had significantly higher water content than the other substrates; although it had high levels of surface evaporation, BSC took up more ground water. Moreover, the structure of BSC supported greater water retention than the four other substrates in our study, providing the moistest environment for lichens. In fact, 60 % of the surface area of the crustose lichenOchrolechia frigida, which was mainly distributed on BSC, was in contact with the substrate. In contrast, the four fruticose lichens had larger surface areas thanOch frigand roughly 90 % air exposure. Initial rates of absorption and evaporation increased with greater thallus surface area, suggesting that water availability for photobionts is strongly affected by both morphological characteristics and substrate water properties, both of which depend on mycobionts. We conclude that lichens show preferences for both morphologies and substrates that promote autotrophic nutrition in the water-limited glacier foreland of the high Arctic region.