Iranian Biology Society Journal of Plant Research (Iranian Journal of Biology) 2383-2592 31 1 2018 04 21 The effects of plant growth regulators and stratification on seed dormancy breaking and parameters of morphological, physiological and biochemical of seedlings of Persian walnut (Juglans regia L.) The effects of plant growth regulators and stratification on seed dormancy breaking and parameters of morphological, physiological and biochemical of seedlings of Persian walnut (Juglans regia L.) 197 207 1179 FA Babak Valizadeh Kaji Arak University Ahmad Reza Abbasifar Journal Article 2016 09 07 Abstract<br /> Abstract<br /> Persian walnut (Juglans regia L.) is an economically important fruit tree of the temperate regions of the world that is cultivated for its fruit and timber. Due to physiological and mechanical dormancy, the walnut seeds often show an inconsistent or low germination percentage, making difficult the subsequent growth of seedlings. The purpose of this experiment was to investigate the influence of stratification periods (30 and 60 days) and different concentrations of plant growth regulators (Gibberellic acid and Kinetin) on seed dormancy breaking and germination of Persian walnut. This experiment was carried out as a completely randomized design with 15 treatments and 20 replicates in condition of greenhouse. Results showed that stratification periods and different concentrations of plant growth regulators had a significant difference on the most parameters investigated (P<0.01), as the treatment of 60 days stratification in combination with 500 ppm GA3 resulting in the greatest seed germination (99.28%), germination rate (2.91 seeds per day), shoot length (24.35 cm), root length (17.50 cm), root volume (7.71 cm3), shoot fresh weight (6.78 g) and root fresh weight (6.58 g). Nevertheless, the highest content of chlorophyll a (18.64 mg/g fresh weight), chlorophyll b (10.62 mg/g fresh weight) and total chlorophyll (29.27 mg/g fresh weight) was related to the treatment of 60 days stratification in combination with 750 ppm Kinetin. Abstract<br /> Abstract<br /> Persian walnut (Juglans regia L.) is an economically important fruit tree of the temperate regions of the world that is cultivated for its fruit and timber. Due to physiological and mechanical dormancy, the walnut seeds often show an inconsistent or low germination percentage, making difficult the subsequent growth of seedlings. The purpose of this experiment was to investigate the influence of stratification periods (30 and 60 days) and different concentrations of plant growth regulators (Gibberellic acid and Kinetin) on seed dormancy breaking and germination of Persian walnut. This experiment was carried out as a completely randomized design with 15 treatments and 20 replicates in condition of greenhouse. Results showed that stratification periods and different concentrations of plant growth regulators had a significant difference on the most parameters investigated (P<0.01), as the treatment of 60 days stratification in combination with 500 ppm GA3 resulting in the greatest seed germination (99.28%), germination rate (2.91 seeds per day), shoot length (24.35 cm), root length (17.50 cm), root volume (7.71 cm3), shoot fresh weight (6.78 g) and root fresh weight (6.58 g). Nevertheless, the highest content of chlorophyll a (18.64 mg/g fresh weight), chlorophyll b (10.62 mg/g fresh weight) and total chlorophyll (29.27 mg/g fresh weight) was related to the treatment of 60 days stratification in combination with 750 ppm Kinetin. https://plant.ijbio.ir/article_1179_dabd8d2ce74e782c65a973ef76fd540b.pdf