A Preliminary Study On Embryo Culture In Prunus Salicina Var.cordata Cv.Younai

Immature and mature embryos of Prunus salicina var. cordata cv .Younai were cultured in vitro. Embryogenic calli were induced from immature embryos and an optimalized maintaining system of calli were established; calli from mature embryos were also induced and maintained; moreover, in vitro germination from mature embryos was preliminarily studied. The results obtained were summarized as follows:1 Induction of calli from immature embryosThe sterilization condition for immature embryos was by 0.1% HgCh for 8min, which survival percentage was up to 80.5%. Immature embryos with the sizes from 1.0 to 2.5mm in diameter were cultured on the WPM medium supplemented with 2.0 mg.L-1 2,4-D, 0.5 mg.L-1 Kinetin, 5 mgL-1 silver nitrate and 3% sorbitol for inducing embryogenic calli. A few small and thin plantlets formed when they were cultured on the WPM medium free of phytohormones.2 Maintenance of calli from immature embryosCalli from immature embryos should be subcultured within 10days after they had been induced, and the inducing media were not suitable for long-term subculture. The concentrations of 0.1~0.3 mg.L-1 2,4-D were beneficial to long-term maintenance of the calli. The lower content of sucrose (1.5%) was favourable to the growth of the calli. Sorbitol is unfavourable as carbon source to the long-termmaintenance of the calli. The best subculture cycle was 15~18 days. Supplementing with phytic acid inhibited the calli from browning and promoted the growth of calli; and activated carbon and polyvinypyrrolidone could also be beneficial to overcoming the browning of the calli.In this experiment, the calli were subcultured alternately on the media containing 2,4-D (0.5 mg.L-1 and 1.0 mgL-1), carbon source (3%sobital and 1.5% sucrose), basic medium(WPM and MS), which was favourable to the maintenance of calli and reducing callus browning.3 Calli induction and in vitro germination from mature embryosThe induction percentage of calli from mature embryos without seed capsule were higher than those with seed capsule. The most optimal medium was WPM medium added with 2.0 mgL-12,4-D, 0.5 mgL-1 Kinetin,1.0 mgL-1gibberellin and 3% sucrose for callus induction. The induction percentage of calli from mature embryos were generally higher than those from immature embryos. Calli from mature embryos could be maintained via the alternative culture method. The differential ability of calli from mature embryos was poor. A number of mature embryos germinated to formed plantlets on the media (WPM and MS) free of phytohormone; and the germination percentage of mature embryos without seed capsule were higher than those with seed capsule. Light was favourable to the germination and development of the mature embryos.