Phytosterol of <Emphasis Type="Italic">Potamogeton maackianus</Emphasis> and its change under the stress of <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis>

The phytosterol in Potamogeton maackianus was identified and quantified. From the hexane extracts analysis of unsaponifiable fraction of P. maackianus by gas chromatography-mass spectrometry(GC-MS), campesterol, stigmasterol and β-sitosterol were the main phytosterols in P. maackianus with the contents of 0.368, 1.17 and 0.824 mg·g⁻¹, respectively. After 7 days’ exposure under M. aeruginosa, the contents of campesterol, stigmasterol and β-sitosterol in P.maackianus increased by 23.1%, 40.4% and 40.8%, respectively. Both the contents of 24-ethyl sterols (sitosterol and stigmasterol) and 24-methyl sterol (campesterol) in macrophytes increased, but the percentage of total sterol composition did not change significantly. This result indicated that the content of 4-demethyl sterols and the second alkylation of the phytosterol side-chain at C-24 in P. maackianus were affected by M. aeruginosa. Biography: ZHANG Shenghua(1979–), female, Ph.D. candidate, research direction: environmental biology.