Adventitious embryogenesis and plantlet regeneration from ovules of unpollinated ovaries of papaya (Carica papaya L.).

摘要

Ovules were excised from unpollinated Carica papaya ovaries before flowering and cultured on media containing cytokinins, auxins and gibberellins. Adventitious embryos were induced only in the culture media with mixed gibberellins and gibberellic acid (GA3) in the dark. No embryos were initiated with cytokinins and auxins, whereas the gibberellin mixture (GA3 >80%, GA1 + GA4 about 10%, minute amount of GA2 + GA7), and GA3 and GA4 individually promoted induction, but GA1, GA5 and GA7 were ineffective. Adventitious embryos were directly induced from the ovules. However, there were many abnormal embryos with malformed cotyledons. The induced embryos were transferred onto a hormone-free MS medium to regenerate plantlets. Plantlets were derived from embryos which had been cultured on media with gibberellin mixture, GA3 and GA4 at respective frequencies of 18.6, 26.4 and 26.9%. The total number of surviving plants after acclimatization was only 44 (7.2%). All acclimated plants were diploid (2n = 18), whereas some of the adventitious embryos were heteroploid and tetraploid (4n = 36). RAPD analyses of the regenerated plants using primers RA1 and RA47 showed that several had different banding patterns from their parents. Therefore, it is suggested that some of the regenerated plants were induced from haploid reproductive cells.