Growth and antioxidant response of Zinnia elegans under salt stress conditions

Irrigating urban landscapes needs other water sources as high-quality water supply is scarce in many parts of the world. Therefore, salt-tolerant plants for landscapes are necessary. A greenhouse experiment was carried out to examine salt stress tolerance of Zinnia elegans‘Magellan’ plants. Saline irrigation startedsix weeks after cultivation of plants with solutions at electrical conductivity (EC) of 0, 2.5, 5, 7.5, 10, 12.5 and 15 dS·m?1. Morpho-physiological characteristics of the plants were measured8 weeks later.Plants became shorter, theirleaf area, chlorophyll contentand overall growth wasstunted as EC of irrigation water increased. Shoot dry weight of zinnias reduced by 93%at EC 12.5dS.m–1 as compared with that of the control.Flower size was reduced by 75% at EC 10dS.m–1ascompared with EC 0 andflower bud opening was ceased at EC 12.5 dS.m–1. Plants died by EC 15dS.m–1 as a result of high ion leakage from damaged cells.Osmoprotectantproline increased by 170%at EC 12.5dS.m–1ascompared with the control.Antioxidant enzyme superoxide dismutase was tripled at the EC 10 dS.m–1while the other detoxifiercatalase was doubled due to the salt stress. Thus, it is concluded that zinnia cultivar ‘Magellan’ used in this study isrelatively tolerant to salinity and can be planted in places with fair soil salinity or when wastewaters with moderate salinity may be used for irrigation.