ABSTRACT
The first stage in fiber development extends from the time cells develop the potential for fiber formation to the time cell elongation begins. Ovule epidermal cells develop the potential to form fibers several days prior to anthesis. In situ fiber cells begin elongation around the day of anthesis. Ovules from 3, 4, 5, 7 and 9 days preanthesis ovaries and ovary sections from 12, 13 and 16 days preanthesis buds were placed on a medium containing Murshige and Skoog salts, B5 vitamins, 100mg/l myoinositol, 30g/l glucose, 0.5mg/l kinetin. 0.1mg/l 2,4-dichlorophenoxyacetic acid and 8.75g/l agar. The cultures were maintained in the dark at 32 C. Fibers were formed on 3, 4, 5, 7 and 9 days preanthesis ovules. After 8 weeks in culture in vitro fibers reached a maximum length of 10mm, diameter of 10-22 µm and the cell wall was 1-3 µm thick. The percentage of ovules producing fibers decreased from 30% to 5% with an increase in the number of days preanthesis. The culture medium supported callus formation and proliferation in addition to fiber formation. Ovules taken 3 through 16 days preanthesis formed callus tissue composed of cells 1-1.5mm long and isodiametric cells (40-60 µm). Ovules were cultured 13 days prior to anthesis and examined on what would be 4 days postanthesis in situ. Most ovules formed callus tissue but some grew to a length of 3mm with very little callus formation. A few ovules had epidermal cells that were 0.2 - l.0mm long. Callus tissue initiated from 3 days preanthesis ovules was subcultured 5 times during a 25 week period. The callus was transferred to a modified Beasley and Ting liquid medium containing 220mg/l CaCI(2), 2mg/l gibberellic acid and 10g/l glucose. After two weeks 19% of the ovule-derived cells were 0.6 - 1.0mm long and 40% had a width of at least O.1mm. Callus tissue derived from hypocotyl cells was placed in the modified Beasley and Ting medium. After two weeks no hypocotyl cells were over 0.6mm long or 0.1mm wide.
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