Responses of zinnia to saline water irrigation - Texas A&M University (TAMU) Scholar

Zinnia marylandica Zahara Series and Z. maritima 'Solcito' perform well in landscapes in hot regions. However, their tolerance to salinity stress is unknown. Two experiments were conducted to evaluate the salinity tolerance of these zinnia cultivars in greenhouse by sub-irrigating or top irrigating plants with saline solutions at electrical conductivity (EC) of 1.3 (control, nutrient solution), 3.0, 4.2, 6.0, or 8.2 dS m-1 for four weeks. When sub-irrigated, plants exhibited salt damage from third week at salinity levels 4.2 dS m-1 and higher and all plants died by the end of 4-week treatment at EC of 6.0 and 8.2 dS m-1. The salinity of the top 2 cm layer at the end of the 4-week treatment was 4 to 6.7 times higher than the salinity of the substrate below the top 2 cm. In the top irrigated plants, salt damaged occurred in the second week and the salt damage symptoms were visible at EC as low as 3.0 dS m-1. The salt damage symptoms were more severe at higher EC levels. Shoot dry weight was lower at higher EC levels in both sub-and top irrigation methods, regardless of species or cultivar. Based on foliar salt damage, mortality and growth reduction, we concluded that the selected zinnias were not tolerant to salinity and should not be planted in landscapes where poor quality water may be used for irrigation. ISHS.

Responses of zinnia to saline water irrigation Conference Paper