title: Physiological and biochemical responses in the leaves of two mangrove plant seedlings (Kandelia candel and Bruguiera gymnorrhiza) exposed to multiple heavy metals.
abstract: The accumulation of heavy metals and their effect on photosynthetic pigments, proline, glutathione (GSH) and phytochelatins (PCs-SH) were studied in the leaves of two mangrove plants seedlings (Kandelia candel and Bruguiera gymnorrhiza) grown for 30 days in the nutrient solution containing four different concentrations of Cd(2+), Pb(2+) and Hg(2+) (T(1), T(2), T(3) and T(4)). An increase in Cd, Pb and Hg content was found in the leaves of both species exposed to multiple heavy metal stress, whereas higher heavy metal levels (>T(1)) led to a remarkable breakdown of chlorophyll in the leaves of both species. The content of proline, GSH and PCs-SH in the leaves of both species exhibited a significant increase in response to heavy metal stress, at least under most of experimental conditions. Increased contents of proline, GSH and PCs-SH in metal-treated plants suggest that metal tolerance in both K. candel and B. gymnorrhiza might be associated to the efficiency of these antioxidants. Moreover, proline, GSH and PCs-SH in K. candel may play more important role in ameliorating the effect of heavy metal toxicity than those in B. gymnorrhiza.
authors.affiliation: Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China. huang gyh@sina.com
authors.forename: Guo-Yong
authors.initials: GY
authors.lastname: Huang
authors.forename: You-Shao
authors.initials: YS
authors.lastname: Wang
mesh_terms: D019216:Metals, Heavy / Q000633:toxicity*; D018515:Plant Leaves / Q000737:chemistry / Q000187:drug effects*; D043982:Rhizophoraceae / Q000737:chemistry / Q000187:drug effects*
chemical_list: D019216:Metals, Heavy