链形藻类的中国新记录属—中眼藻属

中眼藻属(Mesostigma)被认为是与高等植物亲缘关系最近的单细胞鞭毛藻类, 是研究高等植物起源的关键类群之一。已有研究表明中眼藻主要分布于静止的淡水水体中, 诸如池塘、水库和小型湖泊等, 然而中国至今仍未有该藻的报道。本研究在重庆合川和福建九龙江采集到2株单细胞鞭毛藻类, 对其进行形态观察并基于18S rDNA序列进行了系统发育分析。研究结果表明这2株藻为中眼藻属的绿色中眼藻(Mesostigma viride)。此外, 研究从三峡库区的环境DNA中也鉴定出中眼藻的存在, 且主要出现在秋季, 说明秋季可能是在中国内陆采集中眼藻的最佳季节。研究是中眼藻属在中国的首次报道, 为今后的中眼藻相关研究奠定了基础。

MESOSTIGMA, A NEW CHINESE RECORD GENUS OF STREPTOPHYTA

Mesostigma is the most closely related unicellular flagellate algae to land plants, and is one of the key groups for studying the origin of land plants. However, there is no report of Mesostigma in China. Studies have shown that Mesostigma is mainly distributed in static fresh water bodies, such as ponds, reservoirs and small lakes. This study collected several strains of green algae using plankton net in ponds from Hechuan, Chongqing and in reservoirs from Jiulong River, Fujian. In order to identify the species and figure out the phylogenetic position of the green algae, morphological observations under the microscope and phylogenetic analysis by a variety of applications and softwares were accomplished in this study. Both the morphological observation results and the analysis of the phylogenetic tree based on 18S rDNA sequence showed that the green algae collected in this study were Mesostigma viride. In addition, this study also identified the existence of Mesostigma from the environmental DNA of the Three Gorges Reservoir, and the results showed that it mainly appeared in autumn, indicating that autumn may be the best season for collecting Mesostigma in China. This is the first report of Mesostigma in China, laying the foundation for future research on Mesostigma.