The Influence of Temperature on Sunflower (Helianthus annuus L.) Germination and Development

Abstract

Environmental conditions affect plants germination and development. The temperature is one of these factors. The aim of this paper was to evaluate the influence of different temperatures on germination and development of sunflower plants (Helianthus annuus L.). The seeds germinated in different temperatures: 25; 27,5; 30 and 32,5 ºC. Temperatures were controlled in B.O.D chamber. The evaluations were carried out seven days after the beginning of the assay. Germination percentage and seed germination rate, primary root and shoot length, fresh root and shoot biomass were evaluated. Variance analysis and regression analysis were also carried out. It was observed significant effect of temperature on germination percentage and speed rates. Sunflower seeds presented better germination percentile on the 25 to 27,5º C range. High temperatures negatively affected germination speed rate. The higher number of germinated seeds per unit of time was obtained at 30º C. Higher temperatures negatively affected the development of plants, especially on the shoot in comparison to the root.