THE EFFECTS OF COLCHICINE ON GROWTH AND DEVELOPMENT OF SUNFLOWER (HELIANTHUS ANNUUS L.) SEEDLINGS

In the present study we aimed to observe the effects of different doses of colchicine during optimizing the appropriate time and dose on poly-ploid sunflower production. When the sunflower seeds germinated and cotiledonary leaves opened, cotton balls soaked in aqueous solutions of 0.2%, 0.4% and 0.6% colchicine were applied to apical shoots for 12 h in three sets for each concentration. The process was repeated three consecutive days. Morphological, anatomical and photosynthetic pig-ment analyses were performed. According to the results shoot length, stoma number, stoma size, total chlorophyll, chlorophyll a, b and carotenoid contents were decreased. In higher concentrations of 0.4% and 0.6% the reduction was more sensitive. Additionally, SEM results revealed some defects in pollen morphology. Although no pollen was produced in 0.6% colchicine treatment, the pollen grains were tied to each other forming a mass by exine wall bridges in 0.4% colchicine treatment. However these defects were rare in 0.2% colchicine. Our results demonstrated that 0.4% and 0.6% colchicine application for a duration of 12 h induced toxic effects on growth and development of sunflower seedlings.