PDF(Pubmed)
Abstract：
Terrestrial diatoms are widespread in a large variety of habitats and are regularly recorded in biocrusts. Although diatoms have long been known to live in terrestrial habitats, only a few studies have focused on their diversity of ecophysiology. Here we present a study on the ecophysiological performance of five terrestrial diatom cultures from biocrusts, which were collected in sand dunes of the German coast of the Baltic Sea. The sampling sites were selected along a gradient of human impacts on the dunes. The richness of diatom species, roughly estimated from permanent slides, was around 30 species per sampling site. The species abundance was calculated in the same way revealing a high proportion of broken diatom frustules. All diatom cultures established in the laboratory showed no photoinhibition and high oxygen production along a light gradient. The desiccation tolerance differed among the strains, with high recovery observed for Hantzschia abundans and Achnanthes coarctata and low to no recovery for Pinnularia borealis and Pinnularia intermedia. The maximum growth rate for most strains was between 25 and 30°C. These temperatures can be easily reached in their natural environments. Nevertheless, during short-term exposure to elevated temperatures, oxygen production was recorded up to 35°C. Interestingly, two of five diatom cultures (Hantzschia abundans and Pinnularia borealis) produced mycosporine-like amino acids. These UV-protective substances are known from marine diatoms but not previously reported in terrestrial diatoms.
摘要：
陆生硅藻广泛分布在各种生境中，并定期记录在生物锈蚀中。尽管硅藻早就知道生活在陆地栖息地，只有少数研究关注它们的生态生理学多样性。在这里，我们对来自生物锈病的五种陆地硅藻培养物的生态生理性能进行了研究，收集在波罗的海德国海岸的沙丘中。采样点是沿着人类对沙丘的影响梯度选择的。硅藻物种的丰富，从永久性幻灯片粗略估计，每个采样点大约有30种。以相同的方式计算物种丰度，表明破碎的硅藻硅藻壳比例很高。在实验室中建立的所有硅藻培养物都没有光抑制和沿光梯度的高氧产生。菌株之间的脱水耐受性不同，Hantzschiaabundans和Achnanthescoarctata的回收率很高，而Pinnulariaborealis和Pinnulariaintermediate的回收率很低至没有。大多数菌株的最大生长速率在25至30°C之间。这些温度在自然环境中很容易达到。然而，在短期暴露于高温期间，记录到35°C的氧气产量。有趣的是,五种硅藻培养物中的两种（Hantzschiaabundans和Pinnulariaborealis）产生了类似霉菌素的氨基酸。这些紫外线防护物质是从海洋硅藻中已知的，但以前在陆地硅藻中没有报道。
