OBJECTIVETo study the cause of the seeds dormancy of Glehnia littoralis in vitro and to establish plant regeneration methods via somatic embryos.

METHODThe effects of endosperm and exogenous hormone on the seed dormancy breaking of G. littoralis and the effect of hormone concentration on embryonic callus induction and plant regeneration via somatic embryos were observed,

RESULTSThe germination rate of the seeds with 1/3 endosperm was the highest which achieved 31%. TDZ, 6-BA and GA3 treatment could not break seed dormancy but easily lead to abnormal seedlings. Embryogenic callus induction rates was up to 57% on MS supplemented with 1.0 mg x L(-1) 2,4-D. After 20 days culture, embryogenic calli were transferred to MS medium and cotyledonary embryos were formed in 40 days. The regenerated plants were obtained in 20 days.

CONCLUSIONAn effective system of plant regeneration of G. littoralis was established in this study.

Apiaceae ; physiology ; Endangered Species ; Plant Somatic Embryogenesis Techniques ; Plants, Medicinal ; physiology ; Regeneration ; Seeds ; physiology

The somatic embryogenesis in plant is a very complicated and highly ordered process, which is regulated by many internal and external factors. Among them, gene expression and regulation are key factors. Genes encoding regulatory proteins, for example PLANT GROWTH ACTIVATOR, LEAFY COTYLEDON, BABY BOOM, SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE and PICKLE, interact with each other and form a complicated regulatory network. Recent progress on this regulatory network was reviewed on the basis of our study on the PLANT GROWTH ACTIVATOR 37 gene. In addition, future research perspectives on plant somatic embryogenesis were discussed.
Arabidopsis Proteins ; genetics ; Gene Expression Regulation, Developmental ; Gene Expression Regulation, Plant ; Plant Development ; Plant Growth Regulators ; genetics ; Plant Somatic Embryogenesis Techniques ; Plants ; genetics ; Transcription Factors ; genetics

We describe a genetic transformation method of secondary somatic embryogenesis in alfalfa through cotyledon-stage somatic embryos of alfalfa infected by Agrobacterium strain GV3101. The Agrobacterium strain GV3101 contained binary vector pCAMBIA2301 that had gus gene as reporter and npt II gene as selectable marker. The infected primary embryos were induced through series of medium under 75 mg/L kanamycin selection. We obtained the transgenic alfalfa plants. Then, GUS expression in different tissue of transgenic alfalfa was tested by GUS histochemical analysis. Further, the stable integration and transformation efficiency were tested by polymerase chain reaction and Southern blotting hybridization. The result showed that GUS expression was different in different organs of transgenic alfalfa; the copy number of integrated npt II gene was from 1 to 4; the transformation efficiency via primary somatic embryogenesis was 65.82%.
Agrobacterium ; genetics ; Medicago sativa ; embryology ; genetics ; physiology ; Plant Somatic Embryogenesis Techniques ; Plants, Genetically Modified ; embryology ; genetics ; Tissue Culture Techniques ; Transformation, Genetic

In order to broaden Chinese cabbage gene pool, we conducted interspecific somatic hybridization between Chinese cabbage (Brassica campestris, 2n=20, AA) and Cabbage (B. oleracea, 2n=18, CC). Protoplasts were isolated from 10-day-old cotyledons and hypocotyls of young seedlings, and fused by 40% polyethylene glycol (PEG). Fused cells were cultured in modified K8p liquid medium supplemented with some plant growth regulators. Fusion products were characterized by their morphological, cytological and molecular biological traits. The results showed that, a total of 35 regenerated green plants were obtained from 320 calli, the plant regeneration frequency was 10.94%, and eleven of which were survived in greenhouse. All regenerants were true hybrids as confirmed by randomly amplified polymorphic DNA (RAPD) and genomic in situ hybridization (GISH) analysis. Ploidy levels of hybrid plants were determined by chromosome counting and flow cytometry. The sum of the chromosome number (2n = 38) from the two fusion patents were found in 36.4% of regeneratns; another 36.4% had chromosomes range to 58-60; 27.2% had more chromosomes ranges to 70-76. All regenerated plants produced normal flowers. We investigated the pollen fertility and seed set after self-pollination and backcrossing with the parental species. For hybrids with chromosomes more than 38 it was possible to obtain some seeds when they after self-pollination. Within the group of hybrids with 38 chromosomes, seed set were very variable, only 0.11 seeds per pod by self-pollination, 0.23-0.76 by open-pollination, 0.02-0.04 by backcrossing with Chinese cabbage. Progeny lines obtained by self-pollination had larger leaves and leaf shapes intermediate of the parental species. Pollen fertility was gradually recovered in the first and second progenies. The backcrossing progeny lines, as a whole, exhibited morphologies were similar to Chinese cabbage. Morphological variations were observed among the somatic hybrids and their progenies.
Brassica napus ; genetics ; growth & development ; Breeding ; Chromosomes, Plant ; Hybridization, Genetic ; genetics ; Mustard Plant ; genetics ; growth & development ; Plant Somatic Embryogenesis Techniques ; Ploidies ; Pollen ; physiology ; Protoplasts ; cytology ; Random Amplified Polymorphic DNA Technique ; Recombination, Genetic