Effect of Ascophyllum nodosum Seaweed Extract on Growth and Elemental Nutrient Composition of Safflower (Carthamus tinctorius L.) under Salt Stress

Biostimulants have been used in recent years as innovative approaches to stabilize or increase the yield and quality of plants under abiotic stress conditions. Seaweeds, one of the biostimulants, have been used in many cultivated plants and favorable results have been obtained in terms of yield, quality and elemental composition of plant nutrients. Although it is known that safflower plant is sensitive to salt during emergence and germination period, salt and seaweed applications have not been investigated on this plant before. It was aimed to examine the tolerance mechanisms of seaweed applications in safflower plant under salinity stress in terms of some morphological parameters and elemental composition of plant nutrients. The five different doses of salt treatment (0 mM NaCl-distilled water as control, 50 mM, 100 mM, 150 mM, 200 mM) and four different doses of Ascophyllum nodosum seaweed extract (0 g L-1 - distilled water as control, 2 g L-1, 4 g L-1, 6 g L-1) were used as the treatment groups in this study conducted in the climate chamber under controlled conditions. When the figures obtained from safflower plants treated with seaweed in terms of growth parameters were evaluated; root and shoot length, fresh root and shoot weights, dry root and shoot weights generally increased with increasing doses, while relative water content decreased. As salinity stress increased, decreases were generally recorded in all growth parameters obtained. Improved elemental composition of plant nutrients both shoot and root were also observed with seaweed extract applications. In particular, K and Mg in shoot, Ca, Cu and Mg in root increased with increasing seaweed applications. The findings obtained from the study show that seaweed is a promising agricultural application on growth parameters and elemental composition of plant nutrients and reduces the negative effects of salinity stress on safflower plant.