Mobilization of seed reserves during germination and early seedling growth of two sunflower cultivars

The present study was carried out to determine the mobilization of seed storage components of sunflower seeds during germination and early seedling development. Two sunflower cultivars (DUET CL and TR 3080) were used as plant materials. Seeds were germinated for 120 h and samples were taken every 24 h. The total chlorophyll and carotenoid contents of the germinating seeds of both cultivars significantly increased till 96 h, and then decreased. While the total soluble and reducing sugar contents were decreased during the first 24 h, their amounts increased significantly afterwards. The total protein contents of the germinating seeds of TR 3080 and DUET CL decreased from 48.1% and 40.9% to 35.5% and 28.4%, respectively. However, their free amino acid contents were steadily increased during germination and early seedling growth. The oil contents of DUET CL and TR 3080 started to decrease significantly after 72 h and dropped to 41.3% and 40.2%, respectively, at the end of the study. Free fatty acid contents of the seeds increased until 72 h, but decreased thereafter. While, oleic acid contents of the cultivars decreased during the germination period, their linoleic acid contents increased. These results suggest that significant changes occur in the pigment, sugar, lipid and protein metabolisms during germination and early seedling growth period of sunflower.