الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 121 |  |  |
| | | from | 121 | | |
Abstract
This study was carried out at the Experimental Station and Laboratory of Horticultural Department, Faculty of Agriculture, Mansoura University during the two seasons of 2006 / 2007 and 2007 / 2008 to study the effects of seed soaking treatment in distilled water, GA3 (at 500, 1000 and 2000 ppm) or kinetin (at 25, 50 and 100 ppm) either alone or in combination with cold stratification for 45, 90 days and stored seeds before sowing at room temperature for 135 days on seed germination and subsequent seedling vegetative growth as well as chemical constituents of Magnolia grandiflora L. This study consisted of four separate experiments. Each experiment included eight treatments; seven of them were seed soaking treatments in the aforementioned solution for 24 hrs and the eighth one was control treatment (seed without soaking). Each treatment was replicated three times and each replicate included 19 seeds.The obtained results can be summarized as follows: - 1- First experiment: In the first experiment, seeds were soaked in the different solutions for 24 hrs then sowed on Oct., 15th in both seasons. 1.1. Seed Germination (%) Soaking the seeds in all used solutions significantly increased seed germination (%) over control (un–soaked seeds) in both seasons. The highest values of seed germination (%) at all dates of measurements were obtained from the seeds soaked in GA3 solution at the concentration of 2000 ppm in both seasons followed by those of kinetin treatment at 100 ppm, whereas, the lowest values were of control treatment.1.2. Vegetative growth - Seedling grown from all seed soaking treatments were significantly taller than those of control treatment in both seasons. The highest values of plant height (cm) were recorded in the GA3 treatment at 2000 ppm followed by those of kinetin treatment at 100 ppm.- Seedlings resulted from all seed soaking treatments gave significantly higher number of leaves / plant that those of control treatment in both seasons. The highest values in this regard were obtained from the plants of GA3 treatment at 2000 ppm followed by those of kinetin treatment at 100 ppm. 1.3. Chemical constituents - Seed soaking treatments significantly decreased total phenols content in both seeds and in seedlings when compared with control treatment in both seasons. The lowest values of total phenols before and after sowing were determined in the GA3 treatment at 2000 ppm followed by kinetin treatment at 100 ppm. - Seed soaking treatments significantly increased reducing sugars content in both seeds and in seedlings when compared with control treatment in both seasons. The highest values of reducing sugars content (%) before and after sowing were determined in the GA3 treatment at 2000 ppm followed by kinetin treatment at 100 ppm.2. Second experimentIn this experiment, seeds were first soaked for 24 hrs in the different solutions then were cold stratified at 5 ± 1ºC for 45 days and thereafter sowed on Dec., 1st in both seasons.Seed germination (%) Soaking the seeds in all used solutions significantly increased seed germination (%) over control (un – soaked seeds) in both seasons.- The highest values of seed germination (%) at all dates of measurements were obtained from the seeds soaked in GA3 solution at the concentration of 2000 ppm in both seasons followed by those of kinetin treatment at 100 ppm, whereas, the lowest values were of control treatment.2.2. Vegetative growth- Seedling grown from all seed soaking treatments were significantly taller than those of control treatment in both seasons. The highest values of plant height (cm) were recorded in the GA3 treatment at 2000 ppm followed by those of kinetin treatment at 100 ppm.- Seedlings resulted from all seed soaking treatments gave significantly higher number of leaves /plant that those of control treatment in both seasons .The highest values in this regard were obtained from the plants of GA3 treatment at 2000 ppm followed by those of kinetin treatment at 100 ppm.2.3. Chemical constituents - Seed soaking treatments significantly decreased total phenols content in both seeds and in seedlings when compared with control treatment in both seasons. The lowest values of total phenols before and after sowing were determined in the GA3 treatment at 2000 ppm followed by kinetin treatment at 100 ppm. - Seed soaking treatments significantly increased reducing sugars content (%) in both seeds and in seedlings when compared with control treatment in both seasons. The highest values of reducing sugars content (%) before and after sowing were determined in the GA3 treatment at 2000 ppm followed by kinetin treatment at 100 ppm.3. Third experiment :Seeds of the third experiment were first soaked for 24 hrs in the different solutions then were cold stratified at 5 ± 1ºC for 90 days and thereafter sowed on Jan., 15th in both seasons. 3.1. Seed germination (%) Soaking the seeds in all used solutions significantly increased seed germination (%) over control (un – soaked seeds) in both seasons.- The highest values of seed germination (%) at all dates of measurements were obtained from the seeds soaked in GA3 solution at the concentration of 2000 ppm in both seasons followed by those of kinetin treatment at 100 ppm, whereas, the lowest values were of control treatment.3.2. Vegetative growth- Seedling grown from all seed soaking treatments was significantly taller than those of control treatment in both seasons. The highest values of plant height (cm) were recorded in the GA3 treatment at 2000 ppm followed by those of kinetin treatment at 100 ppm.- Seedlings resulted from all seed soaking treatments gave significantly higher number of leaves /plant that those of control treatment in both seasons .The highest values in this regard were obtained from the plants of GA3 treatment at 2000 ppm followed by those of kinetin treatment at 100 ppm.3.3. Chemical constituents - Seed soaking treatments significantly decreased total phenols content in both seeds and in seedlings when compared with control treatment in both seasons. The lowest values of total phenols before and after sowing were determined in the GA3 treatment at 2000 ppm followed by kinetin treatment at 100 ppm. - Seed soaking treatments significantly increased reducing sugars content (%) in both seeds and in seedlings when compared with control treatment in both seasons. The highest values of reducing sugars content (%) before and after sowing were determined in the GA3 treatment at 2000 ppm followed by kinetin treatment at 100 ppm.4. Fourth experiment : Seeds of the fourth experiment were stored for 135 days at room temperature (25 ± 2 ºC) before soaking for 24 hrs in the different solutions and then were sowed on March, 1st in both seasons. 4.1. Seed germination (%) Soaking the seeds in all used solutions significantly increased seed germination (%) over control (un – soaked seeds) in both seasons.- The highest values of seed germination (%) at all dates of measurements were obtained from the seeds soaked in GA3 solution at the concentration of 2000 ppm in both seasons followed by those of kinetin treatment at 100 ppm, whereas, the lowest values were of control treatment.4.2. Vegetative growth - Seedling grown from all seed soaking treatments was significantly taller than those of control treatment in both seasons. The highest values of plant height (cm) were recorded in the GA3 treatment at 2000 ppm followed by those of kinetin treatment at 100 ppm.- Seedlings resulted from all seed soaking treatments gave significantly higher number of leaves /plant that those of control treatment in both seasons .The highest values in this regard were obtained from the plants of GA3 treatment at 2000 ppm followed by those of kinetin treatment at 100 ppm.4.3. Chemical constituents - Seed soaking treatments significantly decreased total phenols content in both seeds and in seedlings when compared with control treatment in both seasons. The lowest values of total phenols before and after sowing were determined in the GA3 treatment at 2000 ppm followed by kinetin treatment at 100 ppm. - Seed soaking treatments significantly increased reducing sugars content (%) in both seeds and in seedlings when compared with control treatment in both seasons. The highest values of reducing sugars content (%) before and after sowing were determined in the GA3 treatment at 2000 ppm followed by kinetin treatment at 100 ppm.