Growth and physiology of ornamental sunflower under salinity in function of paclobutrazol application methods

ABSTRACT The ornamental sunflower has great importance in the floriculture sector due to color and vitality of its flowers. However, production quality flowers decrease under salt stress, which can be mitigated with paclobutrazol application. objective present study was evaluate effects different application methods ‘Sol Noturno’ irrigated brackish waters. experimental design randomized blocks arranged a 5 × 3 factorial scheme, corresponding five electrical conductivities irrigation water - ECw (0.4; 1.9; 3.4; 4.9, 6.4 dS m-1) three (foliar application, via soil control treatment without paclobutrazol), four replicates. increase salinity reduced gas exchange, photosystem II photochemical efficiency, SPAD index, plant height, chapter diameter. or foliar increased stomatal conductance transpiration by 21.09 17.80%, respectively, comparison plants whereas photosynthesis instantaneous carboxylation efficiency 28.33 31.18% 14.40 16.12% foliar, respectively. mainly soil, favored increasing chlorophyll index external diameter, keeping number petals.