Metabolic responses of two <i>Helianthus annuus</i> cultivars to different fluoride concentrations during germination and seedling growth stages

Abstract

The present study was carried out to investigate the effect of sodium fluoride on two sunflower cultivars (Helianthus annuus (Fudek cv. and Earlyflower cv.) during germination and seedling growth stages. Increasing fluoride concentrations significantly decreased total protein and carbohydrate content, as well as amylase activity. However, proline content increased significantly with increasing fluoride concentration. Glutathione content and SOD activity significantly decreased while lipid peroxidation level significantly increased with increasing fluoride concentration. Increasing fluoride concentration in irrigated solution significantly decreased all pigments levels (chlorophyll a & b, total carotenoids and anthocyanins) in a seedling-stage experiment. Application of different concentrations of NaF during germination induced more severe effects than during the seedling stage. The earlyflower cv. was more sensitive to fluoride than Fudek cv.

KEY WORDS: Fluoride, Sunflower, SOD, GSH .lipid peroxidation, germination, seedlings.

Egyptian Journal of Botany Vol.5 2003: 43-54