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Photosynthetic and ultrastructural responses of Ulva australis to Zn stress

Citation

Farias, DR and Schmidt, E and Simioni, C and Bouzon, ZL and Hurd, CL and Eriksen, RS and Macleod, CL, Photosynthetic and ultrastructural responses of Ulva australis to Zn stress, Micron, 103 pp. 45-52. ISSN 0968-4328 (2017) [Refereed Article]


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DOI: doi:10.1016/j.micron.2017.09.010

Abstract

This research evaluated the effect of zinc (Zn) on the ultrastructure and the photosynthetic efficiency of a common green alga. Ulva australis was grown in the laboratory for 7 days under a range of different Zn concentrations (0, 25, 50 and 100 μg L−1). Growth rate (Gr), photosynthetic efficiency (Fv/Fm and ETRmax), photosynthetic pigments, and metal accumulation were measured. Samples of 1 mm length were taken to analyse the effect of Zn on the ultrastructure using transmission electron microscopy (TEM) and cytochemical responses (TB-O and PAS) were evaluated by light microscopy (LM). There were no significant differences in the growth rate, Fv/Fm, ETRmax and the photosynthetic pigments chlorophyll a, chlorophyll b and carotenoids (p > 0.05) after 7 days of Zn exposure. However, TEM revealed cytoplasm retraction, compression of cellulose fibrils, dissembled thylakoids and electron-dense bodies suggesting ultrastructural impacts from metal exposure and accumulation. Cytological analysis demonstrated that Zn affected U. australis cells at the three concentrations tested. The main effect was cytoplasm retraction and a decrease on the amount of starch granules, following exposure at 25 μg L−1 and 50 μg L−1 of Zn. We conclude that concentrations of Zn assessed in U. australis in this research has a short-term cellular effect as revealed by TEM and cytological analysis, demonstrating the importance of measuring a broad suite of endpoints to better understand species responses to environmentally relevant concentrations of Zn. However, U. australis was able to physiologically tolerate adverse conditions, since there was no effect on the photosynthetic performance and growth.

Item Details

Item Type:Refereed Article
Keywords:seaweed, heavy metals, pollution, biomonitor
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Phycology (incl. Marine Grasses)
Objective Division:Environment
Objective Group:Ecosystem Assessment and Management
Objective Field:Ecosystem Assessment and Management at Regional or Larger Scales
Author:Farias, DR (Mrs Daniela Farias Aqueveque)
Author:Hurd, CL (Associate Professor Catriona Hurd)
Author:Eriksen, RS (Dr Ruth Eriksen)
Author:Macleod, CL (Associate Professor Catriona MacLeod)
ID Code:121723
Year Published:2017
Deposited By:Centre for Ecology and Biodiversity
Deposited On:2017-10-12
Last Modified:2017-10-12
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