Metal tolerance in marine diatoms vary between morphotypes, strains, and species due to their long-term adaptations to stochastic environments. The mechanisms underlying this highly variable trait remain a matter of interest in ecotoxicology. In this study, we used several cutting-edge techniques, including a non-invasive micro-test technique, atomic force microscopy, and X-ray photoelectron spectroscopy to examine cadmium (Cd) accumulation and tolerance in the three morphotypes of Phaeodactylum tricornutum. Subcellular Cd distribution, metal transporter expression, and glutathione and phytochelatin activity were also analyzed to characterize the morphology-dependent Cd homeostasis and detoxification. We found that the oval morphotype accumulated more Cd, but was also more Cd tolerant than the other morphotypes. The greater surface binding of Cd to the oval morphotype is attributable to its smaller spherical form, rougher cell surface, and lower surface potential. Moreover, the oval morphotype was less permeable to Cd ions and contained higher phytochelatin and glutathione levels, which explained its higher metal tolerance. Our study offers new explanations for diatom’s adaptations to changing environments that may contribute to its evolutionary success.

海洋硅藻的金属耐受性因其对随机环境的长期适应而在形态，菌株和种类之间有所不同。在生态毒理学中，这个高度可变的特征所依据的机制仍然是一个令人感兴趣的问题。在这项研究中，我们使用了几种最先进的技术，包括非侵入性微测试技术，原子力显微镜和X射线光电子能谱，以检查三角Ph的三种形态类型中镉（Cd）的积累和耐受性。还分析了亚细胞Cd分布，金属转运蛋白表达以及谷胱甘肽和植物螯合素活性，以表征形态依赖性Cd稳态和解毒作用。我们发现，椭圆形形态积累了更多的镉，但也比其他形态更耐镉。Cd与椭圆形形态的较大表面结合是由于其较小的球形，较粗糙的细胞表面和较低的表面电势。此外，椭圆形形态对Cd离子的渗透性较低，并含有较高的植物螯合素和谷胱甘肽水平，这说明其对金属的耐受性较高。我们的研究为硅藻适应不断变化的环境提供了新的解释，这可能有助于它的进化成功。