Aplicação foliar de ácido salicílico em girassol ornamental submetido à deficiência hídrica

Abstract

The cultivation of ornamental sunflower (Helianthuns annuus L.) has been outstanding in the market of ornamental plants for being a crop of easy handling and propagation, and for its beautiful inflorescences with good post-harvest durability. However, water scarcity can adversely affect the growth and development of the crop, causing a decrease in productivity and commercial value. Stress in the plant can be attenuated through the exogenous application of phytonutrients such as salicylic acid, which has a regulatory function in plant metabolism. The objective of this work was to evaluate the effects of salicylic acid application on sunflower cv. Dwarf Garden, submitted to water deficiency. The experiment was conducted using a completely randomized design with five treatments and four replicates: T1 daily irrigation without AS application; T2, T3, T4 and T5 with foliar application of the AS in the dosage of two hundred grams per hectare and intervals of 1, 2, 3 and 4 days without irrigation, respectively. Salicylic acid was applied by foliar spraying and water deficiency was imposed seven days after application of the product. Parameters of growth and crop production were evaluated. According to the results, the increase in irrigation intervals led to a decrease in the following variables: stem diameter, fresh shoot mass, external and internal diameter of the head and fresh mass of the head. The plants that received the treatment T2 and T3 showed growth and production similar to the plants of the control treatment, and only in these treatments the plants reached the commercial standard of diameter of the head.