Spore size, colour and melanin content are hypothesised to be functional in relation to environmental stress. Here, we studied AM fungal spores in arid environments of Australia and in an experimental platform simulating altered rainfall. We used microscopy and image analysis to measure spore colour and size, and a quantitative colorimetric assay to estimate melanin content in spores. In arid sites, melanin content tended to increase with increasing aridity. We observed a large range of spore colours at all sites but found a higher proportion of both dark and light spores, and fewer intermediate colours, in drier sites. Spore abundance and size varied among sites, but neither were related to aridity. In the experimental platform established in a grassland, we found no evidence that altered rainfall influenced spore traits. This study identifies traits associated with environmental stress to inform future work into AM fungal life history and assembly processes.

假设孢子大小，颜色和黑色素含量与环境压力有关。在这里，我们研究了澳大利亚干旱环境和模拟降雨变化的实验平台中的AM真菌孢子。我们使用显微镜和图像分析来测量孢子的颜色和大小，并使用定量比色法评估孢子中黑色素的含量。在干旱地区，黑色素含量往往随干旱程度的增加而增加。我们在所有位点观察到了大范围的孢子颜色，但在干燥的位点中发现了较高比例的暗色和浅色孢子，中间色较少。孢子的丰度和大小随部位而异，但均与干旱无关。在草地上建立的实验平台上，我们没有发现改变降雨影响孢子性状的证据。