Role of copper in improving the seed quality of sunflower (Helianthus annuus)

Abstract

'Morden' sunflower (Helianthus annuus L.) was grown in refined sand at a copper supply ranging from acute
deficiency (0.00065 mg/litre) to excess (6.5 mg/litre) to study the effect of variable copper on growth, biomass,oil
yield,etc. The oil content in seeds was highest at 0.065 mg Cu/litre and compared to this, it decreased more in
deficiency (<0,065 mg/litre) than in excess of copper (6.5 mg/litre). High copper also reduced the biomass, total
seed weight and the activities of polyphenol oxidase, ascorbic acid oxidase and cytochrome C oxidase in leaves. In
sunflower, low copper (<0.065 mg Cu/litre) induced the characteristic visible deficiency symptoms and drastically
reduced the growth. biomass and seea yield accompanied 'by 'lOW sugar concentratiOn and 'lowered activities Of
polyphenol oxidase. ascorbic acid oxidase and cytochrome C oxidase in leaves