DIGITALNA ARHIVA ŠUMARSKOG LISTA
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following formula (ISTA, 1993), where MC is moisture content, IW is initial weight and DW is the dry weight. MC = ((IW – DW) ¸ IW) ´ 100 (1) where; MC refers to the moisture content, IW refers to the initial weight, and DW refers to the weight after drying. In the calculation of 1000 seed weights, the average weight calculation method was used in 8 x 100 samples (ISTA, 1993). The fill rate was calculated in 3 x 100 samples taken from seed weight calculated samples. Coat thickness measurements were made on 100 seeds, that were ground with sandpaper up to half the seed size, by using a digital caliper on the parts where the seed coat was the thinnest and thickest (Figure 1). Storage of the Seeds – Čuvanje sjemena The seeds placed in closed plastic bags can be stored without losing their vitality (Prochazkova and Bezdeckova, 2008). In this study, the dry seeds were placed in storage medium in October 2016 in closed plastic bags with a thickness of 0.04 mm. The seeds were stored at 4 different temperatures as; -5ºC, 5ºC, 15ºC and 25ºC. The seeds were stored in the freezer compartment of a refrigerator at -5ºC, in the refrigerator at 5ºC, and in incubator with adjustable temperature at 15ºC and 25ºC. The seeds were kept in storage environments for approximately 10 months until August 2017. Pretreatments and Experimental Design – Predsjetvene pripreme i plan pokusa In the study, floating in water, in ash solution, scarification in sulfuric acid (98%), and a combination of sulfuric acid and floating in ash solution treatments were made for each storage temperature (Table 1). Ash solution prepared by adding 50 g oak wood ash in 1-liter water. The pH value of the solution was 12.5, and was alkaline. The solution was changed every two days to ensure that the seeds left in the solution had air. The pretreatments were started on the seeds stored in storage environments for approximately 10 months; and on August 24, 2017. Sowing was carried out according to complete random blocks with four replications experimental design in polypots at Ardanuc Forest Nursery, Artvin, Tukey; and a total of 30 seeds were used each replication. Scarification Rates – Stupanj skarifikacije The coat thicknesses of hawthorn species might vary among species, even in the same species (Göktürk et al., 2017). Due to this difference in seed coat thickness, the duration of scarification of the seed coat in sulfuric acid ranged between 1 and 3 hours (Bujarska-Borkowska, 2002; Yahyaoglu et al., 2006). This time is up to 6 hours for some hawthorn species with athickseed coat (Dirr and Heuser, 1987). These durations which was recommended for the hawthorn species (i.e. 1, 3 and 6 hours) were used in determining the scarification rates of azarole in sulfuric acid. In the scarification process, 3 x 10 seeds were used for all duration of scarification, and the seeds were exposed to scarification by adding 5 ml 95%-pure sulfuric acid at 1.83 g/cm3 density in 25-ml beakers. Seed diameter and seed length measurements were made twice, before and after the acid scarification process. The following formulas (Göktürk et al., 2017) were used to calculate scarification rates of seed diameter (Sd) and length (Sl): SRD = ((Sdb – Sda) ´ 100) / Sdb (2) SRL = ((Slb – Sla) ´ 100) / Slb (3) where SRD is the scarification rate on seed diameter, SRL is the scarification rate on seed length, Sdb and Slb are seed diameter and length before being treated with sulfuric acid, and Sda and Sla are seed diameter and length values after scarification in sulfuric acid. Evaluation of Data – Procjena rezultata Once the germinations were completed, the germination percentages (GP) of the seeds for each pretreatment were determined. The GP was computed by dividing the number of germinating seeds counted at twice a week from the |