Absorption of sodium chloride by the halophyte Portulaca oleracea L.
Moshe Halpern1, Joann K. Whalen1 and Donald L. Smith2
1
2
Dept. Natural Resource Sciences, Macdonald Campus, McGill University, QC;
Dept. Plant Science, Macdonald Campus, McGill University, QC.
moshehalpern416@hotmail.com
In Canada, many greenhouse producers are switching to semi-closed irrigation systems
that recycle the water draining from the plant pots. The drainage water is mixed with
fresh water and recirculated through the irrigation system for several weeks until it is
disposed. In water recirculation systems, the increase in NaCl concentration is the major
factor that limits water reuse. These systems would be more efficient if the excess NaCl
could be extracted from recirculating water. The objective of this study was to evaluate
NaCl adsorption by the halophyte P. oleracea (Common purslane). Seeds of P. oleracea
germinated and grew in perlite/peat media for about five weeks. At the six leaf stage
(vegetative growth, before floral initiation), plants were transferred to one litre
hydroponics bottles containing modified Hoagland’s solution (one plant per bottle). The
greenhouse experiment was a completely randomized design with five treatments: 0, 10,
100, 1000 and 10 000 mg/L NaCl added to the hydroponics solution. There were five
replicates of each treatment. The Na and Cl concentrations were measured weekly for a
period of four weeks. The NaCl content of purslane and growth measurements, such as
the dry matter weight of roots, stems and leaves, root length, and leaf chlorophyll
concentration were measured at the end of the experiment (four weeks). Results will be
presented, and the potential of using halophytes like P. oleracea to reduce NaCl
accumulation in water recirculation systems will be discussed.