Effects of salinity on anatomical features and physiology of a semi-mangrove plant Myoporum bontioides

• Published in: Marine pollution bulletin 2014-08, Vol.85 (2), p.738-746
• Main Authors: Xu, H.M., Tam, N.F.Y., Zan, Q.J., Bai, M., Shin, P.K.S., Vrijmoed, L.L.P., Cheung, S.G., Liao, W.B.
• Format: Article
• Language: English
• Subjects: Anatomical features; Animal and plant ecology; Animal, plant and microbial ecology; Antioxidants - analysis; Applied ecology; Biological and medical sciences; Brackish water ecosystems; Catalase - metabolism; China; Ecotoxicology, biological effects of pollution; Estuaries; Fresh Water; Fundamental and applied biological sciences. Psychology; Malondialdehyde - chemistry; Marine; Marine and brackish environment; Myoporum; Myoporum - anatomy & histology; Myoporum - physiology; Myoporum bontioides; Osmosis - drug effects; Peroxidase - metabolism; Photosynthesis - drug effects; Physiological traits; Plant Leaves - drug effects; Plant Stems - drug effects; Proline - chemistry; Salinity; Salt adaptability; Sea water ecosystems; Sodium Chloride - chemistry; Superoxide Dismutase - metabolism; Synecology
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2014.04.003

•M. bontioides, a salt-secreting semi-mangrove, was not a halophilous species.•Photosynthesis and leaf anatomy were significantly reduced by NaCl⩾200mM.•NaCl effect on osmotic chemicals and enzyme activities were mainly at Day 7.•The plant had a relatively low tolerance to salinity, less than 200mM NaCl.•It could be used for the afforestation in freshwater estuary. The effect of different concentrations of NaCl, 0, 100, 200, 300 and 400mM, on the anatomical features and physiology of Myoporum bontioides was investigated. The photosynthetic rates (Pn) were significantly reduced by salt stress, with the lowest values at 400mM NaCl. The content of malondialdehyde (MDA), proline and soluble sugar, as well as the activities of peroxidase (POD) and catalase (CAT) increased at the beginning, but became similar to the control as the experiment proceeded. The NaCl effect on superoxide dismutase (SOD) was different from the other parameters, with a significant reduction at 400mM NaCl at Day 7. Salt glands were found in both upper and lower epidermis, and the ratios of the thickness of palisade to spongy mesophyll tissues increased with NaCl concentrations. The medullary ray was clearly damaged by NaCl at levels of 200 and 300mM. These results demonstrated that M. bontioides could adapt to a relatively low salinity, and was not a halophilous species.