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STUDIES ON THE GERMINATION OF THREE ENDANGERED CENTUREA SPECIES

SEZGIN CELIK

Abstract: Centurea spicata, C. fenzlii and C. kurdica are widely used as ornamental plants in the Mediterranean and East Anatolian regions of Turkey. C. spicata occupies serpentine habitats in the macchia formations whereas C. fenzlii and C. kurdica cover basaltic and dolomitic habitats among the tragacanthic steppe. However, these species are facing a threat of extinction due to overexploitation. As such, an attempt was made to investigate the possibilities for their propagation. For this purpose, the seeds were placed for germination at optimum temperature (25 ± 1 ⁰C) in different concentrations of KNO₃, HCl and NaCl. Two different photoperiods (8 hours light-16 hours darkness-I and 16 hours light-8 hours darkness-II) were used to mimic the natural conditions. Studies on the germination of three species undertaken to evaluate the possibilities to cultivate the native populations at a large scale showed that C. spicata did not germinate at 3 % NaCl, 2-3 % HCl and 3 % KNO₃ under both photoperiods, but germination rate was highest in  1% KNO₃ whereas germination percentage was higher in 0.5% KNO₃ and control group under photoperiod I. Under photoperiod II germination rate was highest in 1% NaCl and control. In the case of C. fenzlii  the germination failed  in 3 % NaCl, 2-3% HCl and  3 %KNO₃ under both photoperiods but  under photoperiod I the germination rate was highest in control and 0.5% KNO₃, whereas the highest percentage germination was examined in control and 1% KNO₃. Under photoperiod II germination rate was highest in 1-2 %NaCl and control, and germination percentage was highest in control and 0.5% KNO₃. In C. kurdica under photoperiod I germination rate was highest in control and 1% KNO₃ but percentage germination was highest in control and 0.5 % KNO₃, whereas under photoperiod II rate of germination was highest in control and 1% KNO₃ and germination percentage in control and 0.5% KNO₃.

Çanakkale Onsekiz Mart University, Sci.& Arts Fac., Biol. Dept., Canakkale, Turkey