Development of sunflower plants under different conditions of water supply

Abstract

Usually lack or excess of water in the soil are harmful to plant development. Therefore, we aimed to evaluate the growth of sunflower plants under different water holding capacity (WHC). The experiment was carried out in a greenhouse; we used sunflower plants (Embrapa 122/V-2000) and four treatments: 60%, 80% and 100% of WHC and a in flooding level, in randomized blocks with four replications. Plants were evaluated weekly between stages V6 to R4. We evaluated the plant height, stem diameter, leaf chlorophyll content, leaves, stems, shoots and roots dry matter, number of leaves, leaf area, and the relationship between roots and shoot dry matter. The results showed that the sunflower plants had greater height and stem diameter when subjected to higher water availability, however, the greatest plant height did not mean a better development of the sunflower. In water stress the chlorophyll increased content was limited, and in treatments with high water availability, the content initially increased, but decreased in latest assessments. With respect to dry matter of stem, root and leaf, number of leaves and leaf area when under 60% of WHC was verified smaller values. For the root/shoot was observed higher values for treatment 60% of WHC. Thus, the better development of these plants was observed when exposed to 80 and 100% of the WHC.