Search Results
You are looking at 1 - 4 of 4 items for :
- Author or Editor: Y.K. Park x
- HortScience x
The development of genetic transformation systems has led to remarkable progress in the area of plant molecular biology. This has included the introduction of useful traits, such as resistance to viruses, herbicides, and insects. Transformed plant cells can be selected, using chimeric genes that confer resistance to toxic drugs, such as kanamycin, hygromycin, streptomycin, gentamycin, and bleomycin. Expression of these chimeric genes in the transformed cells confers the ability to survive and proliferate on the selective medium, while non-transformed cells die. In this study, we report a simple and efficient system to regenerate Chinese cabbage plants and study of the effects of plant growth regulators, AgNO3, initial dark treatment, various antibiotics, and herbicide on shoot induction from hypocotyl or cotyledon of Chinese cabbage. Shoots were induced at various combinations of naphtalene acetic acid (NAA) and benzyladenine (BA) levels. The best combination of plant growth regulators was 2.0 mg/L NAA and 1.0 mg/L BA for cotyledon, and 1.0 mg/L NAA and 5.0 mg/L BA for hypocotyl. The experiment investigating the effect of AgNO3 demonstrated that 16.7 mg/L AgNO3 was effective for inducing shoot regeneration from both of explants. Three to five days of initial dark treatments had significant effects for increasing the number of regenerated shoots; however, different growth regulator combinations showed various responses to duration of dark treatments. The effects of kanamycin, hygromycin, cefatoxime, carbenicillin and phosphinothricin (PPT) on shoot induction from cotyledon and hypocotyl were tested. Shoot induction was completely inhibited by kanamycin at 10 mg/L, hygromycin at 5 mg/L, PPT at 5 mg/L or higher, but not by carbenicillin and cefatoxime.
Leaf disks of potato cv. Kennebec and ND 860-2 (North Dakota potato breeding clone) were cultured on Murashige Skoog (MS) medium supplemented with 6 levels of indole acetic acid (IAA) and 7 levels of zeatin riboside (ZR). Shoots were induced at various combinations of hormone levels. The medium containing 3.5 mg/l IAA and 4.0 mg/l ZR produced the most shoots. Rooted plantlets were grown in the greenhouse. The growth of regenerated plants obtained from the MS medium supplemented with 7.0 mg/l IAA and 3.0 mg/l ZR was significantly greater than those grown from nodal explants. In ND 8602, a leaf chimera with chlorophyll deficient (light yellow) sectors was found in plants regenerated from leaf disks (grown on MS medium supplemented with 3.5 mg/l IAA and 3.0 mg/l ZR) but not in plants grown from nodal explants. Phenotypic variability was also observed for tuber number, size and weight.
This experiment was conducted to identify the effect of various growth retardants on the growth of Aerides japonicum in vitro. Paclobutrazol was found the most effective retardant for reducing the leaf growth of seedling. Ancymidol and uniconazole also showed retarding effects on leaf growth of one, whereas Daminozide didn't. When growth retardants were added to culture medium, leaf length of seedlings was gradually shortened and leaf width became wider than that of control. However, root length was shorter and number of roots and root diameter were greatly increased. On the contrary, at 0.05 and 0.1 ppm uniconazole, growth of leaf and root were enhanced. It was showed that the possibility of using as an additive for good growth of Aerides japonicum seedling in vitro. The activity of GA-like substances was higher in the portion in which growth of seedlings were promoted. It was identified by anatomical observations that the number of stomata and thickness of cell layer in leaf were increased by treatment of retardants.
New cultivars, `SKK 1' and `SKK 2', of Korean mountain ash (Sorbus alnifolia) that had superior morphological features as woody landscape plants were selected from 5000 seedlings of Sorbus alnifolia. Two clones with genetic variation were selected from 1983 to 1994 as landscape plants with large leaf and unique tree form: `SKK 1', which had large leaf and flower, and `SKK 2', with semi-weeping tree form. New selected cultivars of S. alnifolia were successfully grafted and inherited their mother characteristics. Sorbus alnifolia was difficult to propagate by cutting. Therefore, in vitro propagation methods might be used to propagate the superior cultivars. Shoots with apical and axillary buds were excised from 1-year-old seedlings. The explants were cultured on WPM supplemented with 0.5 mg/L BA. Shoots formed from initial cultures were subcultured at ≈4-week intervals onto the same media. To know the best hormone concentration in shoot multiplication, 0.1–3.0 mg/L of BA and 0.1–1.0 mg/L of zeatin were added to each WPM and MS media. The best shoot proliferation and elongation were obtained on MS medium with 1.0 mg/L BA from the whole shoot with the callus-like tissue, whereas the worst results were obtained from shoot tip. A 13-fold proliferation rate was achieved every 4 weeks.