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| ŠUMARSKI LIST 7-8/2021 str. 54 <-- 54 --> PDF |
germination rates can be obtained, as the seeds complete the after ripening process. The effects of pre-treatments applied to seeds stored at appropriate temperatures to increase the germination rate may be more than previously thought. Otherwise, unsuitable storage temperatures may cause low germination rates, deterioration in seeds and a decrease in seed viability (Schmidt, 2000), consequently the effects of the pre-treatments applied may not be accurately determined. Appropriate storage temperatures can also increase the water permeability of the seed coats (Wang et al., 2010). The seeds whose coats do not allow water permeation can lose these properties and allow water permeation in dry storage conditions (Gupta and Singh, 1990). These study findings show that appropriate storage temperatures not only eliminate the germination barrier caused by the immaturity of the embryo, but also ensure the removal of the germination barrier caused by the impermeability of the seed coat. Chemical scarification of the seed coats in sulfuric acid are recommended to eliminate the germination barrier caused by the thick seed coat of hawthorn seeds (Bujarska-Borkowska, 2002; Yahyaoglu et al., 2006). Increased water permeability of the seed coat can also be achieved by pretreatment with alkaline chemicals (Hou and Simpson, 1994). Therefore, alkaline ash solution treatments are also recommended (Gokturk and Yilmaz, 2015) to ensure water permeability of the seeds. In order to reveal the actual effects of these proposed pretreatments, it is important to determine the appropriate storage temperature, which is important for the viability of seeds, and to determine the effects of pre-treatments according to storage temperatures. However, there are limited studies to determine suitable storage temperatures for hawthorn seeds. Hawthorn seeds do not usually germinate in the year the fruit ripens due to germination barriers. With the germination that occurs in the seeds after the warm and cold process under natural conditions shows that the germination rate can be increased if the seeds are stored in warm or hot temperatures. Azarole (Crataegus azarolus var. pontica (K. Koch K. I. Chr) is one of the hawthorn species represented in Turkey, and is a rare species growing naturally in the provinces of Artvin, the Coruh Valley, Erzurum and Nevsehir in Turkey (Donmez, 2004). Although it is a rare species, it has been the subject of this study due to it being an important income-generating species and the high production demand of its edible fruits by the local inhabitants. In the present study, the following aims were investigated: (I) Determining the effect of different storage temperatures on germination percentages; (II) Determining the effect of the pretreatments on the germination of the seeds of floating in water, floating in an ash solution, scarification in sulfuric acid, and floating in an ash solution + scarification in sulfuric acid; and (III) Determining whether storage temperatures and pretreatments have interactive effects on the germination of the azarole seeds. MATERIALS AND METHODS MATERIJALI I METODE Materials – Materijali The azaroleseeds originating fromArtvin and Yusufeli used in the study were obtained from the fruits collected in October 2016 from trees in areas where azarole naturally spreads (41° 07’ 00” N, 41° 37’ 48” E, 1150 m, S). The storage and pretreatments of the seeds were performed at Artvin Coruh University, Forestry Faculty Seed and Afforestation Laboratory, and sowing of the seeds was carried out at Ardanuc Forest Nursery (41° 06’ 56” N, 42° 05’ 15” E,750 m, W) of Artvin Regional Directorate of Forestry. Methods – Metode Extracting Seeds and Determining Seed Characteristics – Vađenje sjemena i određivanje značajki sjemena The seeds of the azaroleswere separated from the pulp by wet maceration. Then, the seeds were dried in the shade for 10 days at room temperature (20-25°C). The determination of moisture content, which is an important factor in seed vitality during the storage duration, was performed before the dried seeds were placed in storage environments. Moisture content was determined by the air-oven method (105°C, 24 h). Seed moisture content was calculated by the |