Colored calla lilies (Zantedeschia K. Koch) are popular cut flowers and potted plants, which have a recommended
irrigation water electrical conductivity (EC) of less than 1.5 dS m−1. Calla lilies exposed to an
NaCl imposed EC up to four times the recommended EC showed no reductions in visual quality, with
maintenance of growth, albeit at a reduced rate. The leaves of the plants in all treatments were able to
maintain turgor even though there were decreases in carbon assimilation rate of 50–80% compared to
the control in the 50 mM NaCl treatment starting 35 days after treatment. This reduction in photosynthesis
is most likely responsible for the reductions we observed in growth. Within this same time period
we observed osmotic adjustment of 0.16–0.20 MPa and reductions in stomatal conductance of 53–97%
compared to the control. We propose that osmotic adjustment and reductions in stomatal conductance
were integral in maintaining leaf turgor throughout the stress period. By 63 days of treatment the cation
content(Na+, Ca2+ and Mg2+)in the leaves ofthe 25 and 50 mM NaCltreatments were two and three times
the concentration observed in the control respectively. We hypothesize that osmotic adjustment is the
result of ion accumulation. Osmotic adjustment in addition to reductions in stomatal conductance may
be adaptations to ensure that colored calla lilies survive stressful conditions until their dormant period
and reemerge successfully under more favorable conditions.