Some Physical and Morphological Properties of Wild Sunflower Seeds

Abstract

As part of a study to characterise and examine the use of wild sunflower species ( Helianthus petiolaris Nutt), some physical properties and morphological characteristics of seeds from different locations in Argentina were determined. The oil content ranged between 27% and 30% (wb) and the moisture content varied from 8·9% to 10·4%. The average length, width, and thickness of the seed, measured with a micrometer, were 4·5, 2·02, and 1·2 mm, respectively. The calculated mean values of seed equivalent diameter, surface area, and sphericity were 2·25 mm, 16·2 mm 2 , and 0·48, respectively. The bulk and true densities measured with a hectolitre tester and by picnometry, respectively, were 350 and 399 kg/m 3 . The angle of repose ranged between 28·6° and 30·2°. The morphological characteristics as well as the hull thickness and percentage were also evaluated by scanning electron microscopy. The hull thickness and percentage had mean values 0·07 mm and 21%, respectively. Achenes presented straight and double hairs and a morphological study showed a pericarp structure with an amorphous and lignified fibre layer and air cavities between the inner parenchyma and the cotyledon.