Salt Tolerance of Ten Perennial Plants in Asteraceae

Asteraceae is one of the largest plant families, and is important primarily for its many garden ornamental species. Rooted cuttings of ten perennial species (Chrysactinia mexicana, Eupatorium greggii, Leucanthemum × superbum, Melampodium leucanthum, Santolina chamaecyparissus, Symphyotrichum oblongifolium, Tagetes lemmonii, Tetraneuris scaposa, Viguiera stenoloba, and Wedelia texana) in Asteraceae were transplanted in plastic containers with Metro-Mix 360 on 6 October 2014. Two weeks later, treatments were initiated by irrigating plants with nutrient solution at electrical conductivity (EC) of 1.3 dS·m^-1, saline solution at EC of 5.0 dS·m^-1 (EC5), or at EC of 10.0 dS·m^-1 (EC10). Four weeks after treatments, experiment was terminated. Upon termination, visual foliar salt damage (leaf edge burn, necrosis, or discoloration) was rated on a score of 0 to 5, where 0 = dead; 1 = severe (over 90%); 2 = moderate (50-90%); 3 = slight (<50%); 4 = good quality with minimal foliar damage; and 5 = excellent with no visible foliar damage. Above-ground parts including stems, leaves and flowers were harvested and dry weight (DW) was determined. V. stenoloba, San. chamaecyparissus, and E. greggii at EC5 or EC10 had minimal foliar damage with their DWs decreased by 11% to 18% and 22% to 28%, respectively. L. × superbum also had minimal foliar damage, but EC5 and EC10 reduced its DW by 40% and 59%, respectively. M. leucanthum and Tag. lemmonii at EC5 had minimal foliar damage with 33% and 42% of DW reduction, respectively, while those at EC10 had moderate foliar damage with 56% and 71% of DW reduction, respectively. C. mexicana at EC5 and EC10 had slight foliar damage with 56% and 64% reductions in DW, respectively. Sym. oblongifolium and W. texana at EC5 had slight foliar damage with 28% and 6% reductions in DW, whereas those at EC10 had moderate foliar damage with 45% and 35% reductions in DW. Tet. scaposa at EC5 had moderate foliar damage with 58% of DW reduction, while all Tet. scaposa plants at EC10 died. In summary, V. stenoloba, S. chamaecyparissus, and E. greggii were more salt tolerant than the other seven species.