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The Scientific World Journal
Volume 2015, Article ID 107823, 12 pages
http://dx.doi.org/10.1155/2015/107823
Research Article

Toxic Effects of Ethyl Cinnamate on the Photosynthesis and Physiological Characteristics of Chlorella vulgaris Based on Chlorophyll Fluorescence and Flow Cytometry Analysis

MOE Laboratory for Earth Surface Processes, College of Urban & Environmental Sciences, Peking University, Beijing 100871, China

Received 29 January 2015; Revised 10 April 2015; Accepted 7 May 2015

Academic Editor: Huansheng Cao

Copyright © 2015 Yang Jiao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The toxic effects of ethyl cinnamate on the photosynthetic and physiological characteristics of Chlorella vulgaris were studied based on chlorophyll fluorescence and flow cytometry analysis. Parameters, including biomass, (maximal photochemical efficiency of PSII), ФPSII (actual photochemical efficiency of PSII in the light), FDA, and PI staining fluorescence, were measured. The results showed the following: (1) The inhibition on biomass increased as the exposure concentration increased. 1 mg/L ethyl cinnamate was sufficient to reduce the total biomass of C. vulgaris. The 48-h and 72-h EC50 values were 2.07 mg/L (1.94–2.20) and 1.89 mg/L (1.82–1.97). (2) After 24 h of exposure to 2–4 mg/L ethyl cinnamate, the photosynthesis of C. vulgaris almost ceased, manifesting in ФPSII being close to zero. After 72 h of exposure to 4 mg/L ethyl cinnamate, the of C. vulgaris dropped to zero. (3) Ethyl cinnamate also affected the cellular physiology of C. vulgaris, but these effects resulted in the inhibition of cell yield rather than cell death. Exposure to ethyl cinnamate resulted in decreased esterase activities in C. vulgaris, increased average cell size, and altered intensities of chlorophyll a fluorescence. Overall, esterase activity was the most sensitive variable.