Plant Regeneration from Rice Microspore Cultures

벼의 소포자 배양을 통한 식물체 재분화

Efficient plant regeneration system was established through the culture of rice (Oryza sativa L.) microspores. Microspores released by anther shedding culture developed into proembryos and calluses in B5 medium within two weeks of culture. The optimal hormone and carbon sources were dependent on the genotypes used. Microspore's viability decreased rapidly in culture time, therefore less than 3% of the total microspores were viable at the 9th day when the first microspore division was observed. Of two types of microspores (pollen dimorphism) observed in culture, only the P-grain, larger microspores than normal one was able to divide. Using 4',6-diamidino-2-phenylindole (DAPI) fluorescence staining, it was confirmed that the symmetrical division of uninucleate microspore was the first step leading to continuous microspore development. Microspore-derived proembryos and calluses were regenerated to plants in N6 medium containing 1 mg/L NAA and 5 mg/L kinetin, and 78.3% of the regenerated plants were haploids.