Servet Çalışkan

Variations in carbon and nitrogen ratios and their effects on seed germination in Cupressus sempervirens populations

This study investigated the variations in the carbon (C), nitrogen (N), and C/N ratios in the seeds of the Mediterranean Cypress (Cupressus sempervirens L.), a typical forest tree of the Mediterranean Region. The data were gathered from populations distributed across Turkey. We also evaluated the relationship between these variations and germination parameters such as the germination percentage (GP) and mean germination time (MGT). All of the evaluated characteristics demonstrated statistically significant variations among the populations. The GPs were generally low and varied between 14% in Datça and 51% in the Köprülü Kanyon. The MGTs ranged from 14.9 in the Köprülü Kanyon to 18.9 in Marmaris. In addition, the C ratios varied between 46% in Marmaris and 52% in the Köprülü Kanyon, while the N ratios ranged from 1.1% in Beycik and Göksu to 1.8% in the Köprülü Kanyon. Furthermore, we observed a positive correlation between the GP and the C and N contents (R2 = 0.51 and R2 = 0.49, respectively) but found a negative correlation between the MGT and the C and N contents (R2 = 0.56 and R2 = 0.32, respectively). Moreover, with regard to the combined C and N seed ratios of the regression models, R2 = 0.95 for the GP and R2 = 0.87 for the MGT, and the populations with higher quantities of C and N in their seeds had shorter MGTs and higher GPs.

Effects of heat shock on seed germination of Turkish red pine (Pinus brutia)

Fire plays an important ecological role in Mediterranean-type ecosystems. Many Mediterranean plant species exhibit enhanced germination capacity when exposed to heat. In the present study, the effect of high temperatures and exposure times on germination of Turkish red pine (Pinus brutia) was analyzed in order to reveal the response of seeds to fire and the implications on species regeneration. Seeds were heated to a range of temperatures (from 75 to 170 oC) and exposure times (from 30 seconds to 30 minutes) similar to those obtained in surface soil layers during natural fires. In total, twenty treatments were performed. Seed germination percentages and germination values were calculated for each treatment. The results of ANOVA performed for germination values showed that temperature had a significant effect. Germination percentages increased in thermal treatments at 70 oC for 10, 15, 20, 25, and 30 min; at 105 oC for 10, 15, 20, and 25 min, and at 130 oC for 1 and 2 min. The increase in both temperature and exposure times generally decreased the germination percentage especially at 130 °C and over in comparison with the control. Maximum germination percentage was reached in the treatment at 130 oC for 1 min while the minimum germination was reached at 130 oC for 10 min.

Effects of carbon and nitrogen content on seed germination of calabrian pine (Pinus brutia) populations

Semillas de pino de Calabria (Pinus brutia) recolectadas de 15 poblaciones fueron analizados en su contenido de carbono (C) y nitrogeno (N). Ademas fueron evaluados los porcentajes de germinacion (GP) y tiempos medios de germinacion (MGT) de las semillas segun sus concentraciones de carbono y nitrogeno, relacion C/N, masa total de carbono (CM) y masa total de nitrogeno (NM). Excepto en las relaciones C/N, las variables mostraron diferencias significativas entre las poblaciones. La mayor concentracion de carbono de las semillas fue de 54 %, y la mas baja fue de 50 %. Las concentraciones de nitrogeno en las semillas variaron de 2,6 a 3,2 %. Las correlaciones mas altas se encontraron entre el GP de las semillas estratificadas (GPFS) y las concentraciones combinadas de carbono y nitrogeno (R2 = 0,65), y entre los GPFS y concentraciones de carbono (R2 = 0,63), ambas significativas. Las relaciones entre los parametros de germinacion y las concentraciones combinadas de carbono y nitrogeno, asi como los rasgos CM y NM fueron generalmente mayores que cualquiera de las evaluaciones individuales, a excepcion de las concentraciones de carbono.

Seed crop investigation of Pinus sylvestris, Pinus nigra subsp. pallasiana and Pinus brutia in Turkey

Seed crop investigation of Pinus sylvestris, Pinus nigra subsp. pallasiana and Pinus brutia in Turkey