الفهرس 
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Abstract
in Egypt for multipurpose uses. It is well known in Egypt with the name of “Karkadeh”, its
purplish sepals (calyx and epicalyx) are the most important economic parts of the plant
which is used in both food as Jam and Jelly, and cosmetic industries as a source of natural
colouring agent. (Kalt et al., 1992).
In the meantime, karkadeh is considered a very popular beverage and valuable
medicinal plant due its effect on lowering and/ or adjusting the blood pressure without
producing any side effect (El-Meleigy, 1989). Being high is anthocyanin,Roselle petal is
both a good colorant and potentially a good source of antioxidants. However, owing to the
high reactivity of anthocyanin during processing and storage, more information is needed
to clarify the relation between the coluor and antioxidant activity. Roselle seeds have an
economic value as a source of oil where it reaches 20%. There is no doubt that the need for
ditional edible oils well be increased due to the growth of population over the world and
increases their demands of it. Therefore, the current work on renewable resources for oils
and fats are required to increase the quantity and quality of edible oils. The fatty acid
profile of karkadeh indicates its importance for human consumption as well as its
suitability for vegetable oil processing (Mostafa et al., 2005).
Plant growth regulateors play a crucial role for horticultural crop either botaniculy
or\and industrially. Among of these chemicals is gibberellic acid. Hence, gibberellins play
a vital role in enhancing phenylalanine ammonia Layase (PAL) and tyrosine ammonia
layase (TAL) synthesis and in turn increased anthocyanin contents (Heeock et al. 1997).
Gibberellins are fundomental to plant development especially with respect to the growth of
stems. Low leaves of Gibberellins will prevent plant from reaching their natural height.
Gibberellin synthesis inhibitors are extensively used in grain production to keep stems
eretically shoot shorter and thicker stems provide better support and resist weather
conditions better too.
Biofertilization becomes to important factor to increase the availability of
phosphorous in soil or applied as a fertilizer. Mycorrhizal fungi and phosphate dissolving
bacteria are considered as a biological fertilizers which have an important role in the
solubility of P and enhancing its absorption by plant (Radwan, 1998), Also, Arbuscular
mycorrhiza is the most ancient and widespread type of mycorrhizae symbiosis. Phosphorus
uptake and growth of host plants are stimulated by AM fungi. In return, host plants provide
carbohydrates for their fungal partners (Smith and Read 1997).
The phosphate solubilizing bacteria effect is, generally, due to the production of
organic acids by these organisms. They are also known to produce amino acids, vitamins
and growth promoting substance like indole acetic acid (IAA) and gibberellic acid (GA3)
which help in better growth of plants.
For the previously mentioned reasons, the cultivated area of Roselle is increasing,
gradually, in Egypt for local utilization and export ation. Otherwise, more investigation
application about of plant regulators and biofertilization for this crop are still needed for
improving its growth and yield parameters of this crop.
Therfore, the abjective of the present investigation was carried out in order to study
the effect of gibberellic acid and biofertilization in growth attributes, seed yield and
chemical constituents of Roselle plant as follows:
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Chapter Two