The Effect Of Organic Carbon Source And Plant Growth Regulator On Growth And Microcystin Production Of Microcystis Aeruginosa

This research indicated that two organic carbon sources (glucose and sodium acetate) could significantly stimulate the growth of Microcystis aeruginosa. The stimulating effect was the most remarkable when the initial concentration of glucose was 30 mg·L^-1 or when the initial concentrations of sodium acetate were 500mg·L^-1 and 800mg·L^-1. Unlike sodium acetate, higher concentrations of glucose (80mg·L^-1 and 100mg·L^-1) could inhibit the growth of Microcystis aeruginosa obviously. Besides growth, low concentrations organic carbon sources (glucose:10mg·L^-1 and 30mg·L^-1, sodium acetate: 200mg·L^-1) could also accelerate the accumulation of the microcystin(MC) in microcystis cells. In addition, we found out that organic carbon sources could influence photosynthetic pigment contents and photosynthetic efficiency. Especially when the growth of M. aeruginosa was accelerated, the contents of photosynthesis center pigment (Chla) and photosynthetic efficiency (F_v/F_m) would decrease, while the contents of CPC and APC would increase. These results would not only help to discuss the growth and physiological metabolism of M. aeruginosa theoretically, but also imply that the organic pollutant may had a remarkable influence on the forming and MC production of M. aeruginosa bloom.Different plant growth regulators had different effect on the growth and MC production of M. aeruginosa. When dealt with NAA (0.1¹5mg·L^-1) or IBA (0.1²0mg·L^-1), both the total Chla contents and the cell densities of M aeruginosa were higher than the control. Low concentrations of NAA could increase F_v/F_m, at the same time the MC contents per cell may decrease evidently. When the initial concentrations of IBA were high, the F_v/F_m and the MC contents were higher than control. Both 2ip (0.5-3.0mg·L^-1) and 6-BA (0.3³.0mg·L^-1) could stimulate the growth of M. aeruginosa, and the stimulation effect would be more obvious when the initial concentrations of 2ip and 6-BA were higher. When the initial concentrations of 2ip were 0.3mg·L^-1 and 0.5mg·L^-1, the MC contents increased obviously, when the initial concentrations of 2ip werw more than 1.5mg·L^-1, the MC contents descended. The same trend could also be observed of 6-BA, 0.5mg·L^-1 and 1.5mg·L^-1 could favor the accumulation of MC. Certain concentrations of GA3 (0.5⁵.0mg·L^-1) could accelerated the total Chla contents and the...