Effects of cold stratification pretreatment and pH level on germination of Centaurea tchihatcheffii Fisch. et Mey. seeds

Abstract

Centaurea tchihatcheffii Fisch. Et. Mey. is a critically endangered (CR) plant species due to destruction of habitat, strong anthropogenic pressure, biotic and abiotic factors. It grows in limited areas in Gölbai district of Ankara, Turkey and in the world. It is very necessary to conserve it and prevent its extinction. Previous studies emphasise that low germination rate of its seed is primarily due to deep seed dormancy. Therefore, studies was done on C. tchihatcheffii seeds, to investigate the effects of cold stratification for different periods (90, 120 and 150 days) and different pH values (pH 6.5, 7.5 and 8.5) on seed germination. The highest germination percentage (58.89 ± 6.39%) was observed in seeds stratified for 150 days at all pH values of growing media, followed by seeds stratified for 120 days (42.78 ± 4.57%). An increase in pH level had negative effects on seed  germination, the lowest germination (27.22 ± 4.18 %) was determined at pH 8.5.

Key words: Centaure tchihatcheffii, critically endangered, seed  germination, stratification, pH values.