Mangroves of several species can easily be grown in hydroponics or as pot-plants: at present we have Aegiceras corniculatum, Avicennia marina, Bruguiera exaristata, B. gymnorrhiza and Rhizophora stylosa in our glasshouses. However the morphology of the root-system in these conditions differs from field-grown plants, and the physiology of aeration of the roots will be different too. During our investigations of root gas-exchange in Avicennia marina it became clear that for any real understanding of gas movement in the roots it was necessary to grow the plants under controlled tidal conditions. The main practical reason for this was the need to be able to obtain complete isolated root systems of known age and provenance for physiological studies. To this end we designed a very simple tidal system consisting of a series of pumps and time switches which pumped water between two domestic bath tubs in a cycle which approximated to a tidal cycle, although the fluctuations of water level possible were much less than those naturally occurring even in Sydney. The results obtained with plants from this system, which are reported in detail elsewhere (Curran, 1985; Curran, Cole and Allaway, 1986), were as follows.
Firstly, the pneumatophores are air-spaces has ample capacity to supply oxygen to the roots when they were exposed at ‘low-tide’. Secondly, the amount of air stored within the root system was adequate to cope with the respiratory demand of the roots during a normal ‘high tide’ of about 6 hours, keeping the oxygen level high enough for aerobic respiration. Encouraged by these results from the prototype, we then built the large artificial tidal systems described in this paper; in this system the movement of water levels can approximate that experienced in estuaries in the Sydney area.
How to Cite:
Curran, M., Allaway, W.G. and Cole, M., 2009. Artificial tidal systems for growing mangroves.. Wetlands Australia, 5(2), pp.70–77. DOI: http://doi.org/10.31646/wa.93