الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Micropropagation of the horticultural plants has many advantages over the conventional vegetative propagatton and its commercial use in the production of the ornamental and forestry plents. However, its commercially widespread use for major crops, this technique is still restricted as a result of the relatively high production costs. The ( high cost by invitro cuture may be due to the low rates of rooting and survival plantlets during the acclimatization in ,. addition to high costs of labours and laboratory facilities required. Begonia rex-cultorum Fam.”Begoniaceae” are attrative foliage and flowering ornamental plants. They are easy to propagate vegetatively by stem cuttings, leaf cuttings and tip cuttings or by splitting. Leaf cutting is the most commercially method used. Gardenia jasminoides Fam:’Rubiaceae” is the perennial woody flowering greenhouse plant. The plants produce beautiful heavy perfumed flowers. This plant speci~s includes several cultivars; veitchii is the only cultivar cemes to flower in winter. Gardenia plants are propagated readily by terminal shoot cuttings, several years are required to produce enough plants from a nearly released cultivar. Rapid propagation in vitro using shoot tips could alliviatethis problem. Paulownia tomentosa (Princess or Empress trees) Fam. Bignoniaceae•is an Eastern Asian genus ,is a fast growing deciduous tree. The wood is strong and lightweight can be employed for several purposes, in addition to the medicinal use (washing hair and skin). The trees reach 40-50 ft, flowers are in clusters whitish lavender flowers appear perior the leaf appearance in early spring. As the tree has a rapid growth with high level of drought resistance, it has 3potential for increased utilization in the production of bioillass and wood productioa. Seeds are the most satisfactory means of fropaga tion also, root cuttings may be used. Several factors such as type of explant, composition of the culture media and the different supplements affecting the efficiency of this technique in the plant propagation. The aim of the work presented in this Thesis was to investigate the effect of type of exp1ants of the three different plant species( Begonia rex-cu1toru Gardenia jasminoides var.veitchii and Paulownia tomentosa var. pa1lida) ,compostion of the media and growth regulators supplements on the micr~propagation of these plants. Also, the effectSof gamma-irradiation on Bego~ia rexculto and sodium cu1ure deon Pau1ownia tomentosa var, pa11ida• in vitro culture were Investigated ,