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Taurus cedar (Cedrus libani A. Rich.) achieves its broadest natural distribution on Taurus Mountains. The species optimum is in altitudebetween 800 and 2100 m. However, this altitude may descend to 530 m (in groups) and 470 m (individually) in Finike province , and reach 2400 m on Bolkar Mountains-Aydos Mountain. In addition to the main distribution of this species, isolated marginal populations are locally available near Sultandağları-Dort River, Emirdağı-Çaykışla, Tokat-Erbaa-Çatalan, Tokat-Niksar-Akıncı Village and Konya-Sağlık (Günay, 1990; Boydak, 1996).
In Central Anatolian, Taurus cedar is widely used for afforestation purposes together with Anatolian black pine (Pinus nigra Arnold.). This region has semi-arid climate characteristics. Fourthy percent of Turkey’s lands are under this climate, and represent the main potential areas for afforestation. This increase the interest in Taurus cedar. However, differences are observed in the growth of the species depending on the local conditions (e.g. soil and climate). Adittionaly differences among populations were detected based on genetic parameters (Fady et al., 2008). Taurus cedaris assumed to be a frost- and drought-resistant species and is used in the afforestation practices in Turkey after some extreme events. As to last inventory data;, 19 populations of cedarwere selected for gene conservation and 23 populations registered as seed stands (Ayan and Yer, 2016a; Ayan et al., 2016b).
As the effects of climate change are intensely discussed, Taurus cedar is considered as a strategic, key species with its extended and variable gene pool in Turkey (approximately 500 000 ha) and its high adaptive capability. Taurus cedar is also considered as a potential species for afforestation programmes. In this regard, investigating adaptive biochemical indicators of Taurus cedarpopulations and detecting heir genetic variation hold critical importance.
Reproductive material’s quality has direct impact on the success of plantation. The most important criteria for seeds are high viability and resistance to stress in addition to physical and genetic purity (McDonald, 1999; Güney et al., 2013). Seed viability and resistance to stress are highly dependent on the seed’s majority level and chemical composition in addition to genetic factors. Chemical composition of seeds basically includes carbonhydrates, fats, proteins and cellulose in the membrane. Traces of compounds such as hormones, alkaloids, lectins, proteinase inhibitors, phytin and raffinose are also found in the chemical composition of seeds (Ayaz et al., 2011).
The ratio of seed chemicals in seeds also vary based on the age of the mother plant, soil characteristics, climate changes, seed harvest time, preharvest and postharvest processes and the mechanical effects arising during harvest and under storage conditions (Güney et al., 2013). Insufficiencies resulting from one of the abovementioned factors effect the chemical composition of the seed, thus impairing the quality, and resulting with up to 75% reduction in the germination capability (McDonald, 2004). From this aspect, limited studies are available on seed storage chemical content of forest trees, impairment of cellular integration (lipid peroxidation- malondialdehyte (MDA)), enzymatic activities of ascorbate peroxidase (APX), guiacol peroxidase (GuPX), catalase (CAT) and superoxide dismutase (SOD), as well as determination of α-amylase enzyme activity.
In this research; Proline, total soluble protein, MDA, Hydrogen peroxide (H2O2) amounts and activities of APX, GuPX, CAT, SOD and α-amylase enzymes were investigated for the seed samples of optimal and marginal Taurus cedar populations.
MATERIAL AND METHODS
MATERIJALI I METODE
Sample populations – Istraživane populacije
Seeds from five core populations and from a marginal population of Taurus cedar, used in the research, were harvested in 2016, mast seed production year. For the purpose of the research, 6 provenances selected from natural stands and representing different regions were used (Tab. 1).
Chemical Analyses – Kemijska analiza
Proline, protein, MDA and H2O2 in the seed samples were detected by use of the methods by Bates et al. (1973), Bradford (1976), Velikova et al. (2000). Detection of enzymatic activities in the samples was carried out by pulverization of fresh leaf sample in 0.5 g liquid nitrogen and its homogenization with 50 mM (ph 7,6) KH2PO4 (pH=7) 5 ml buffer solution including 0.1 mMNa-EDTA. The homogenized samples were centrifuged at +4 °C (15000 rpm) for a period of 15 minutes. Enzyme activities were analyzed in this supernatant. APX was spectrophotometrically determined using the method introduced by Nakano and Asada (1981) at 290 nm (E=2,8 mM cm-1) by measuring the oxidation rate of the ascorbate; CAT activity was spectrophotometrically determined with the method introduced by Bergmeyer (1974); GuPX activity was detected with the modified method (Lee and Lin, 1995), and SOD enzyme activity was determined using the method applied by Cakmak et al. (2010). α-amylase activity of the seeds was calculated as the amount of starch hydrolyzed per 1 mg protein, using the method by which BSA is used as a standard (Morais and Takaki, 1998).
Statistical analyzes – Statistička analiza
The experiments were done in three replicates. Statistical analyzes of the obtained data were performed through