Study On The Plant Tissue Culture And The Flower Development In Rhododendron Hybridum Hort.

This study was on the plant tissue culture and the flower development with Rhododendronhybridum Hort..The investigation of the morphological differentiation in flower buds, flower organs,valvular stamen and the development in megaspores and microspores, expounded its basicregularity in the reproductive growth phase by means of the technique of traditional paraffin section.This article constructed rapidly propagation system of Rhododendron hybridum Hort. with its stemand the tip of stem as explants by tissue culture, discussed the cause of low fecundity.From this research, the main results were as follows:1. Rhododendron hybridum Hort. was umbel or raceme. The flower buds morphologicaldifferentiation was two or three months before blow, and developed gradually inflorescence anlage.In some phase, the flower buds would enter dormancy. The flower buds morphologicaldifferentiation was obvious acropetal. The more the organ was tender, the closer it was to theterminal bud.2. The mature anther had four microsporanges. Many anamorphic anther appeared, and wasporicidal dehiscence. Many pollen was aboryive. The development of anther wall was basic type. Itwas the glandular tapetum. The microspore mother cells underwent meiosis, each producingtetrahedral tetrad of microspores. The microspores was not separated and became compound pollengrain. The cytokinesis division was successive type. Mature pollens were 3-celled. The location ofreproductive cell was immobile, and was distant from the center of tetrad. The pollen had fourgermination aperture, and was global or close to sphericity. Its surface had more or less trichome.3. The pistil had six carpels. It was axial placenta. But it was different from the orthodox axialplacenta, the carpels was not only involute, but also entered ovary, and became the especialstructure. A lot of ovule vegetated on the structure. The stigma surface was cloven into six parts,and had papillary structure. Rhododendron hybridum Hort. was superior ovary, six ventricle,anatropous ovule, bitegmic and upgrowth, tenuinucellate ovule. Its micropyle canal was long andnarrow. The mature megaspore was quadrate. The delevoping payway of megaspore waspolygonum type.4. The young stamen was complete unaided. Most of them changed into petals stage by stage.A spot of them had rudimental anther, but the filament changed into petals. The external petals wereoriginal, but the inside petals were from the variation of stamen. 5. In the investigation of plant tissue culture, the optimum disinfection method was using 0.1%solution of mercuric chloride, and the disinfection last 6 min; The optimum culture medium ofinducement callus and sub culture was reformativeMS+2-ip (6mg/L)+NAA (0.5mg/L)+Vc(100mg/L); The optimum culture medium of adventitious buds was reformativeMS+2-ip(2mg/L)+NAA (0.1mg/L)+Vc (100mg/L); The optimum culture medium of shoods wasreformativeMS+2-ip (4 mg/L)+NAA (0.1mg/L)+Vc (100mg/L); The optimum culture mediumof rooting was 1/3 reformativeMS+0.5 mg./LNAA+Vc (100mg/L); The optimum pH of cultureexplants was 5.2 to 5.3.