Responses of Suaeda maritima to flooding and salinity

Alhdad, Gazala (2013) Responses of Suaeda maritima to flooding and salinity. Doctoral thesis (PhD), University of Sussex.

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Abstract

Suaeda maritima is an annual halophyte commonly found in salt-marshes. Its salt
tolerance has been well studied, though there is little published on the effect of
simultaneous waterlogging. The effects of saline waterlogging on growth, antioxidants
(glutathione and total polyphenolic compounds, antioxidant activity) and oxidative
damage were investigated with simulated tides in a controlled glasshouse and on plants
collected from the field. Flooded shoots possessed higher levels of antioxidants than
those from plants growing in well-drained situations, in the glasshouse and the field.
The effects of hypoxia, (simulated in nutrient solution by flushing with nitrogen in a
solution containing a low concentration of agar, which limits convection within the
solution and so the transport of oxygen from the air) were determined on growth and
trace metal concentrations, in plants grown in different concentrations of artificial
seawater (100 and 350 mM Na+ at low pH, > pH 5.5), in sand/mud irrigated with halfstrength fresh seawater (at high pH, ca 7-8) and in different concentrations of
manganese and iron in solution culture. High salt concentration reduced accumulation
of trace metals in plants. Optimal growth occurred in 14 μM Fe and 1 mM Mn.
Accumulation of trace metals was reduced at high pH, with more accumulating in the
roots than the shoots. Hypoxia increased soluble sugars in shoots and roots, and this was
affected by the salt concentration. Hypoxia also caused adventitious root development
in hydroponic experiments, while in sand, adventitious root development was greater in
drained than flooded conditions. Hypoxia significantly reduced shoot sodium
concentration, sodium flux and bypass flow, at low and high salt concentrations. In high
salt conditions, S. maritima reduced its transpiration rate and improved its water use
efficiency. It was also shown that the roots contained high lactate concentrations under
aerated and hypoxic conditions. S. maritima demonstrated many adaptations for
tolerating extreme hypoxia.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Life Sciences > Biology and Environmental Science
Subjects: Q Science > QK Botany > QK0900 Plant ecology
Depositing User: Library Cataloguing
Date Deposited: 28 Feb 2013 14:28
Last Modified: 08 Sep 2015 14:32
URI: http://sro.sussex.ac.uk/id/eprint/43812

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