Ação de bioestimulante no crescimento, desenvolvimento e teor de flavonoides em calêndula (Calendula officinalis L.)

Abstract

Calendula officinalis L. (Asteraceae), known as calendula or marigold, is an annual plant and is widely used worldwide as medicinal and ornamental plant. The objective of this work was to evaluate the effect of biostimulant Stimulate®, applied by foliar spray, on the development, in the production of flowers and the content flavonoids in marigold. The experiment was conducted in greenhouse conditions, in Avaré-SP. Seedlings were obtained from commercial seed marigold (Calendula officinalis L., cv. Dobrada Sortida), and the experiment was conducted in plastic pots containing a mixture of organic substrate, loam and sand (ratio 1:1:1). Treatments consisted of different doses of the product Stimulate®, applied by foliar spray, as follow: T1= 0 (distilled water); T2= 3 mL L-1; T3= 6 mL L-1; T4= 9 mL L-1; T5= 12 mL L-1 and T6= 15 mL L-1, applied after 20 days of transplanting the seedlings to pots, carrying out 10 consecutive applications of the product, in the early-morning hours. Biometric evaluations of plants growth were performed at 30, 60 and 90 days after transplanting (height, number of leaves, dry weight of shoot and root) and during the reproductive phase (number of flowers, fresh and dry weight of flowers and content of flavonoids). The experimental design was completely randomized, with 6 treatment and 8 replicates in each treatment, a total of 48 pots. Data were tabulated and submitted to analysis of variance and regression analysis, observing the behavior of the variables according to Stimulate® doses Applying Stimulate® in marigold by foliar spray was not effective in increasing the vegetative growth and total flavonoid content in flowers. In relation to flowering, the Stimulate® application may be used as efficient management technique to provide an increased production of flowers per plant.