Colony formation is a crucial characteristic of , a cyanobacterium known for causing cyanobacterial harmful algal blooms (cyanoHABs). It has been observed that as colonies grow larger, they often become less densely packed, which correlates with a decrease in light penetration. The objective of this study was to investigate the effects of light limitation on the morphological variations in , particularly in relation to the crowded cellular environment. The results indicated that when there was sufficient light (transmittance = 100 %) to support a growth rate of 0.11±0.01 day, a significant increase in colony size was found, from 466±15 μm to 1030±111 μm. However, under light limitation (transmittance = 50 % – 1 %) where the growth rate was lower than 0, there was no significant improvement in colony size. in the light limitation groups exhibited a loose cell arrangement and even the presence of holes or pores within the colony, confirming the negative correlation between colony size and cell arrangement. This pattern is driven by regional differences in growth within the colony, as internal cells have a significantly lower frequency of division compared to peripheral cells, due to intra-colony self-shading (ICSS). The research demonstrates that can adjust its cell arrangement to avoid excessive self-shading, which has implications for predicting and controlling cyanoHABs. These findings also contribute to the understanding of cyanobacterial variations and can potentially inform future research on the diverse phycosphere.

中文翻译：

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理解cyanoHABs的潜在差距：群落蓝藻微囊藻的光依赖性形态变化

菌落形成是蓝藻的一个重要特征，蓝藻以引起蓝藻有害藻华 (cyanoHAB) 而闻名。据观察，随着菌落变大，它们的密度通常会降低，这与光穿透力的降低相关。本研究的目的是研究光限制对形态变化的影响，特别是与拥挤的细胞环境相关的影响。结果表明，当有足够的光照（透光率= 100%）以支持0.11±0.01天的生长速率时，发现菌落尺寸显着增加，从466±15μm增加到1030±111μm。然而，在生长率低于 0 的光照限制（透光率 = 50% – 1%）下，菌落大小没有显着改善。在光限制组中，细胞排列松散，甚至集落内存在孔或孔，证实了集落大小和细胞排列之间的负相关性。这种模式是由集落内生长的区域差异驱动的，因为由于集落内自遮蔽（ICSS），内部细胞的分裂频率明显低于外周细胞。研究表明，可以调整其细胞排列以避免过度的自遮蔽，这对预测和控制氰基HAB具有重要意义。这些发现也有助于了解蓝藻变异，并有可能为未来对多样化藻圈的研究提供信息。