The effect of salinity on Chrysanthemum 'Amiko red'

High salinity in irrigation water is considered to be amongst the most important factors of plant stress that can cause reduced growth, nutrient deficiencies, and toxicities. Salinity symptoms of ornamental plants additionally can reduce their commercial value depending on plant tolerance. Chrysanthemums are popular ornamental plant species. The effect of irrigation water containing 0 (control), 2.5, 5, 10, 20, and 40 Mm NaCl on the plant growth of potted chrysanthemum 'Amiko red' under greenhouse conditions was presented. Toxicity symptoms started to appear on the leaf edges of the plants two weeks after the start of the treatments. While maximum plant height was calculated at 40 mM NaCl, the diameter of the inflorescences was significantly reduced at the same concentration. Maximum efficiency of PSII (Φ_PSIIo) was significantly reduced at 40 mM NaCl. The operating efficiency of PSII photochemistry (Φ_PSII) was significantly reduced at 20 mM NaCl; where, a significant increase in leaf thickness was obtained. Maximum fresh weight of shoots and roots were obtained at 0 and 2.5 mM NaCl; while, corresponding dry weights showed no significant differences between various NaCl treatments. As regards to substrate hydraulic properties, salinity did not affect the substrate's water retention curve, it did affect the saturated hydraulic conductivity. Shortly after treatments were applied, the commercial value of Chrysanthemum 'Amiko red' was negatively affected even at low NaCl concentrations. Generally, the growth of greenhouse potted plants of Chrysanthemum 'Amiko red' was negatively affected at concentrations greater than 5 mM NaCl which became significant at 20 and 40 mM NaCl.