SCUTELLARIA BAICALENSIS GEORGI CONTROLS CYANO-BACTERIAL BLOOMS AND BENEFITS TO AQUATIC ECOSYSTEM.

Cyanobacterial blooms are amongst the most harmful blooms, and can lead to the deterioration of aquatic ecosystems, simultaneously affecting humans, flora and fauna due to the production of cyanobacterial toxins. A Chinese herb (S. baicalensis Georgi) was chosen to control cyano-bacterial blooms in waters. The results showed that the M. aeruginosa growth expressed by chlorophyll-α concentration was totally inhibited by the decoctions of S. baicalensis Georgi at doses of ≥l0 μg when the initial concentration of M. aeruginosa was 670 μg L^-1. The field experiment showed that the cyanobacterial blooms in the ponds treated with the decoctions of S. baicalensis Georgi were significantly controlled in cyanobacterial blooms period from April to June, 2008. The active ingredients in the herb such as flavonoids, could significantly decrease the effective quantum yields and interrupt the electronic transports in photosystem two (PS II) reaction centers in M. aeruginosa cells, which led to the failure of photosynthesis of M. aeruginosa. Simpson's diversity index of macrophytes, zooplankton and bacteria with flaA gene indicated that the application of S. baicalensis Georgi increased the macrophyte, zooplankton and bacterial diversity and improved the growth conditions of their habitats. This study provides a promising emergency measure to control harmful algal blooms in practical waters, and benefits to the aquatic ecosystem. [ABSTRACT FROM AUTHOR]