الفهرس 
ACKNOWLEDGMENT
FertilizationOnly 14 pages are availabe for public view
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Abstract
This investigation was carried out in the Experimental Farm of Assiut University during 2009 and 2010 seasons to study the combined effect of NPK mixtures and growth-retarding paclobutrazol application on producing an acceptable pot-plant of Cestrum nocturnum, L. Besides, certain chemical composition in leaves were determined to verify the nutritional status of plant. Fertilization treatments; N-P-K (0-0-0), (5-5-5), (10-5-5), (5-10-5) and (5-5-10) were prepared from granulated commercial fertilizers; ammonium nitrate (33.5% N), calcium superphosphate (15% P2O5) and potassium sulphate (50% K2O). Each mixture was added at a rate of 50 gm per plant divided into ten equal portions at 3-week intervals from May 5th to October 30th of both seasons. Besides, the plants received one or two sprays of paclobutrazol (PP-333) at 0, 250 and 500 ppm, the first spray of 9th May and the second one at 24th May of the two seasons.
On April 15th, plants were transplanted into 25 cm-clay pots and arranged in randomized complete blocks in a split-plot design, NPK mixtures as main-plots and PP-333 treatments as sub-plots, each treatment replicated four times.
The following results were obtained:
- All NPK treatments significantly increased plant width, number of branches and leaves, leaf area, total leaf area per plant, and fresh and dry weights of the aerial parts and whole plant compared with the control.
- NPK treatments did not show significant increments in plant height, stem diameter and leaf fresh weight, while a slight decrease in fresh weight of square centimeter per leaf, and a great reduction in hight-width ratio were found.
- Most NPK mixtures significantly increased shoot-root ratio, while they showed insignificant increments in fresh and dry weights of roots.
- NPK mixture of (5-5-5) was more effective treatment on stimulating the vegetative and root growth characteristics, it showed the lowest hight-width ratio as a result of compactness.
- NPK mixtures did not affect flowering date, while most of them significantly increased flowering period, number of flowers per plant, and fresh and dry weights of flowers.
- NPK mixture of (5-5-5) was more effective treatment on improving the flower characteristics, it increased flowering period by about twenty days.
- Paclobutrazol treatments showed significant decreases in plant height, and significant increase in plant width that induced a great reduction in height-width ratio. Besides, they significantly increased stem diameter, number of branches and leaves per plant, and significantly decreased leaf area with increasing the concentration or frequency of application. Insignificant increments in shoot-root ratio and leaf fresh weight compared to control were observed.
- Paclobutrazol twice applications at 250 ppm was the most effective treatment on stimulating the foliage and root growth measurements as produced the greatest number of branches and leaves, the largest total leaf area per plant, the heaviest fresh weight of square centimeter per leaf, the heaviest fresh and dry weights of the aerial parts, roots and whole plant, and gave the lowest height-width ratio.
- Mostly, once and twice sprays with PP-333 at 500 ppm were more inhibitory on the shoot and root growth measurements.
- Paclobutrazol twice applications at 250 ppm was more effective treatment on improving flower characteristics, it induced early flowering by about twenty two days, increased flowering period by twenty six days, produced the highest number of flowers per plant, and showed the heaviest fresh and dry weights of flowers, while it resulted in the lowest number of leaves to produce one flower.
- Paclobutrazol twice applications at 500 ppm significantly reduced number of flowers, and fresh and dry weights of flowers, while it significantly increased carbohydrates-nitrogen ratio in comparison with the other PP-333 treatments.
- Chemical analysis showed that NPK mixtures significantly increased leaf contents of nitrogen, phosphorus, potassium, magnesium and iron, while calcium concentration was significantly decreased. Besides, total carbohydrates and photosynthetic pigments content were significantly increased compared to control.
- NPK treatment of (5-5-5) showed the highest concentrations in the nutrient elements studied, as well as, total carbohydrates, chlorophyll ”a”, chlorophyll ”b” and total chlorophyll ”a+b”, while it did not affect carotenoids. This treatment raised carbohydrates nitrogen ratio in leaves.
- Paclobutrazol twice applications at 250 ppm resulted in the highest concentrations in nitrogen, phosphorus, potassium and iron in leaves, and showed a slight decrease in carbohydrates-nitrogen ratio.
- Leaf contents of magnesium, total carbohydrates chlorophyll ”a”, chlorophyll ”b”, total chlorophyll ”a+b” and carotenoids were increased with increasing PP-333 concentration or the frequency of application, while calcium showed the reverse effect.
- The interaction effects among the treatments appeared that the combined treatment of NPK (5-5-5) with PP-333 twice applications at 250 ppm was more effective on producing Cestrum nocturnum, L. as an acceptable pot-plant with compact growth and early flowering as a result of high leaf contents of nutrient elements, carbohydrates and pigments. This treatment could prove a useful technique for commercial production of Night-Blooming jasmine for using as indoor flowering pot-plants.