Salt uptake and shoot water relations in mangroves
In: Aquatic Botany. Elsevier Science: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0304-3770; e-ISSN 1879-1522, meer
|  |
| Trefwoorden |
Accumulation > Ion accumulation
ISEW, Thailand, Rayong
Mangroves
Osmoregulation
Properties > Biological properties > Tolerance > Salinity tolerance
Properties > Chemical properties > Salinity
Uptake
Avicennia alba Blume [WoRMS]; Bruguiera gymnorhiza (L.) Lam. [WoRMS]; Heritiera littoralis Aiton [WoRMS]; Xylocarpus granatum J.Koenig [WoRMS]
Marien/Kust; Brak water |
| Author keywords |
mangrove; salinity; water potential; ion concentrations; osmoregulation |
| Auteurs | | Top |
- Paliyavuth, C.
- Clough, B.
- Patanaponpaiboon, P.
|
|
|
| Abstract |
The effects of salinity on water relations and ion concentrations were investigated in seedlings of the mangroves Avicennia alba, Bruguiera gymnorrhiza, Heritiera littoralis and Xylocarpus granatum grown at salinities of 0, 10, 20, 30, 40 and 60 pm. All four species survived and grew at salinities ranging from 0 to 40 pm, but none survived at a salinity of 60 pm. The concentration of sodium and chloride in the xylem sap increased with increasing salinity in both A. alba and B. gymnorrhiza. Sodium and chloride concentrations in the xylem sap of A. alba grown at 40 pm salinity both reached 114 mol m-3, about 15% of the external concentration around the roots. The xylem sap of B. gymnorrhiza grown at 40 pm salinity, by contrast, contained only 7.0 mol m-3 sodium and 4.1 mol m-3 chloride, about 1% of their concentrations in the external solution around the roots. The results indicated that B. gymnorrhiza, which does not have salt-secreting glands, was more effective at excluding salt than A. alba, which has salt-secreting glands. Analysis of pressure-volume curves showed that the bulk modulus of elasticity increased with increasing salinity. This was accompanied by a decrease in shoot water potential, mainly associated with a reduction in shoot osmotic potentials with increasing salinity. The decrease in osmotic potential was attributed to increasing solute concentrations, particularly sodium and chloride, in the leaves of all species except H. littoralis, which had little sodium and chloride in the leaves. |
|
