• Applied Biological Chemistry
• /
• v.36 no.3
• /
• pp.197-202
• /
• 1993

In order to explore the brassinosteroid-active component in Perilla frutescense, methanol extract of immature seeds was purified by sequences of solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 chromatography, charcoal adsorption chromatography and Bondesil chromatography. The activity of brassinosteroid was monitored by the rice inclination test and its presence could be confirmed in each purification step. The purified active components were seperated by silica gel adsorption chromatography. The seperated main and minor active brassinosteroid fractions were identified as castasterone and homobrassinolide, respectively, by HPLC. We acknowledge that our work is probably the first report of endogenous brassinosteroid in Perilla frutescense. The content of brassinosteroid in Perilla frutescense as converted into brassinolide was $0.5{\sim}0.8\;ng/g$ fresh weight.

• Korean Journal of Weed Science
• /
• v.12 no.2
• /
• pp.110-123
• /
• 1992

To investigate the safening effect of dymron against cinosulfuron, the responses of 104 rice cultivars and lines to single and mixture treatments of cinosulfuron [3-(4.6-dimethoxy-1,3,5-triazin-2-yl)-1-[2-(2-methoxyethoxy)-phenylsulfonyl]-urea] and dymron [1-(${\alpha}$, ${\alpha}$-dimethylbenzyl)-3-p-tolyl urea] were evaluated. The responses of 104 rice cultivars and lines to cinosulfuron were differed. Among the rice cultivars, growth of Calrose, Dasukei, Hwajinhyeo, and Milyang 105 was significantly inhibited by cinosulfuron but there was no inhibition in Daeseongbyeo, Iri 371, Jangseongbyeo, Taebaegbyeo and IR 74. The japonica types were generally inhibited more than the indica and indica${\times}$japonica types. When Kwangmyungbyeo was treated with the mixtures of cinosulfuron 48g and 96g ai/ha with dymron 450g ai/ha, the inhibition of plant height was significantly reduced regardless of dymron concentrations. With increase in cinosulfuron concentration, the safening effect of dymron against cinosulfuron was more evident in plant height than fresh weight. On the other hand, dymron did not have any safening effects of cinosulfuron on Echinochloa crus-galli at any concentrations. The mixtures of dymron and cinosulfuron produced antagonistic effects on the plant height regardless of rice cultivars and treatment concentrations. At cinosulfuron 24g ai/ha, the effects of the mixtures of cinosulfuron and brassinolide on the plant height of Kwangmyungbyeo and IR 74 were similar irrespective of brassinolide concentrations but the inhibition of Kwangmyungbyeo was greater than that of IR 74 as the concentrations of cinosulfuron increased. The effects of the mixtures of cinosulfuron at concentration of 96g ai/ha with various ABA levels on the plant height of both Kwangmyungbyeo and IR 74 showed synergistic effect regardless of ABA concentration. However, the response of fresh weight of both cultivars treated with cinosulfuron at 96g ai/ha with ABA synergisism was observed in Kwangyungbyeo while IR 74 showed antagonism.

• Korean Journal of Weed Science
• /
• v.7 no.1
• /
• pp.84-89
• /
• 1987

This study was conducted to determine the combining effects of a synthetic brassinolide such as homobrassinolide (HBR) with auxin types on the curvature of radish petiole. HBR has no direct effect on the petiole curvature of radish, regardless of concentrations used. Among the natural known plant growth regulators, NAA at 100ppm showed the highest ourvature at 12 hours after treatment. The synthetic auxins such as 2,4-D and MCP resulted in about three times greater effect on curvature than the untreated control, and their effects lasted till 36 horns after treatment, showing much better effect on curvature than that of the natural auxin types of plant growth regulators. The mixture of MCP at 3 ppm with HBR at 100ppm increased petiole curvature of radish seedlings as much as three times greater than that of a single application of HBR. However, the mixture of HBR at 100 ppm plus 2, 4-D at 100ppm increased the petiole curvature of radish seedlings about eight times greater than that of the HBR single application, showing existance of strong synergistic reaction and the most effective combination, and suggesting possibility of a prectical implementation in agriculture.

• Korean Journal of Weed Science
• /
• v.7 no.1
• /
• pp.78-83
• /
• 1987

This study was attempted to evaluate the combining effect of HBR (homobrassinolide) with the known growth regulators such as GA (gibberellic acid), BA(6-benzyl aminopurine), IAA (indole-3-acetic acid), B-9 (N-dimethylamino succinamic acid) and CCC (2-chloroethyl-trimethylammonium chloride) on the growth of radish hypocotyl. A single application of HBR increased hypocotyl growth as its rates increased from 0.1 to 1.0 ppm, showing a maximum increase at 1.0 ppm. GA and BA had no direct effects on hyopcotyl growth, but IAA showed some effect as its concentration increased. However, the mixed application of HBR with GA, BA and IAA increased the length of radish hypocotyl as the concentration of HBR became higher. The mixture of HBR with GA and BA showed antagonistic reaction on radish hypocotyl growth, but synergistic effect was shown in the higher rate mixture of HBR with IAA in the range of HBR at 0.03 to 0.30 ppm with IAA at 3.0 to 10.0 ppm, but antagonistic or additive response at the mixture of low rates. An increased growth of hypocotyl by HBR was ified by CCC, showing the strong antagonistic reaction, but B-9 was not able to ify HBR's effect on hypocotyl growth.

• Proceedings of the Zoological Society Korea Conference
• /
• 1999.10b
• /
• pp.208.1-208
• /
• 1999

No Abstract, See Full Text

• Applied Biological Chemistry
• /
• v.36 no.5
• /
• pp.376-380
• /
• 1993

To investigate the presence of the brassinosteroid substances in immature Oryza sativa L. cv Tongjinbyeo seeds, the methanol extract was purified by the sequential use of solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 chromatography and charcoal adsorption chromatography. The activity of brassinosteroid was monitored by the rice inclination test and its presence could be confirmed in each purification step. The purified active components were separated by silica gel adsorption chromatography and Sephadex LH-20 chromatography. Brassinosteroid substances in separated active fractions were identified as castasterone, teasterone and 6-deoxocastasterone by HPLC. Our work is probably the first report of endogenous brassinosteroids in Oryza sativa seeds. The content of brassinosteroid in Oryza sativa seeds as converted into brassinolide was $0.5{\sim}1.5\;ng/g$ fresh weight.

• Journal of Plant Biotechnology
• /
• v.7 no.3
• /
• pp.161-167
• /
• 2005

Brassinosteroids are steroidal plant hormones and are known to modulate physiological and cellular response in a wide range of plant species. Considerable insights has been achieved of the physiological role of brassinosteroid in Brassica species in the past few years, but their effect on direct organogenesis has not been extensively studied. In this sense, under optimal basal media and growth conditions we tested the cellular and organogenic response of 24-epibrassinolide (EBL) in a variable concentration (0.1 to $5.0\;{\mu}M$) and Zeatin (Z) (1.0 to $100\;{\mu}M$) and their synergic effect on hypocotyl explants of cauliflower and broccoli. The isolated EBL accelerated cell elongation and promotes direct organogenesis. One micromolar EBL + $10\;{\mu}M$ of Z was the most efficient combination for cell elongation, cell differentiation as well as for organogenesis. A suppressing effect on root induction was confirmed for all the tested hormone levels. The general results indicate a synergic effect of EBL-Z and EBL potentates Zeatin activity, at least in certain tissues. Besides de genetic factors, we can speculate that the natural hormone concentration in the explants might affect the responses by application of exogenous growth regulators. Experiments with new plant growth regulators, like brassinolide, are important aiming to maximize or accelerate plant regeneration for in vitro multiplication or for genetic transformation.

• Journal of Plant Biotechnology
• /
• v.30 no.4
• /
• pp.411-419
• /
• 2003

The potent biosynthetic precursors, 24$\alpha$-methylcholesterol and 24$\alpha$-methylcholestanol, and the endogenous brassinosteroids (BRs), castasterone (CS) and 6-deoxocastasterone (6-deoxoCS), were identified from shoots of maize seedlings. In addition, the presence for activities of several enzymes involved in the late C6-oxida-lion pathway from 24$\alpha$-methylcholestanol to CS was demonstrated in the plants. However, activity for brassinolide (BL) synthase which catalyze the conversion of CS to BL, the last step of the late C6-oxidation pathway, was not detected in the enzyme solution obtained from the maize shoots. Together with the fact that BL was not identified from the maize shoots, these results strongly suggested that BRs in the maize shoots are biosynthesized during seedling growth and the active BR in the shoots is not BL but CS.

• Journal of Life Science
• /
• v.17 no.12
• /
• pp.1729-1733
• /
• 2007

Brassinolide insensitive associated receptor kinase 1(BAK1) is a critical component that play an important roles in signaling of brassinosteroid biosynthesis. Brassinosteroid-deficient and -insensitive mutants showed the characteristic of dwarf symptom. The nutrient deficient tomato showing stunt phenomenon was selected from soiless cultivation system using modified Sonneveld hydroponic solution. Twenty eight protein spots showing different expression levels compared to the control were isolated from extracts of stunted tomato leaves by 2D PAGE analyses. Significantly down-regulated 6 protein spots out of 28 protein spots were analyzed and sequenced by MALDI-TOF mass spectrometry. The protein spot having pI=4.5 and MW=24 kDa was identified as a signal protein, BAK1, which is directly related to brassinosteroid biosynthesis. In addition, five other protein spots were identified as BCK1, cystein proteinase, sulfutase, peroxidase and zinc finger factor respectively, and they were also signal proteins related to brassinosteroid biosynthesis. Furthermore, amplification of 500bp of BAK1 mRNA by RT-PCR using a primer set of peptide matched regions was inhibited conpared to that of the wild type. The results sugested that the BAK1 might be regulated at the transcription level in response to nutrition applications.

• Journal of Integrative Natural Science
• /
• v.1 no.1
• /
• pp.24-31
• /
• 2008

Brassinosteroids (BRs) are a special class of plant steroid hormones that are essential for normal growth and development. Part of confusion is whether BRs are unique to plants, because they have overlapping physiological roles with other better-studied hormones and with physiological responses caused by light. In systems designed to assay for cytokinins, the effects of BRs vary. We measured hypocotyl length for testing the ability of brassinolide (BL) to rescue double mutant between det2 and the photoreceptor null mutant phytochrome B (phyB). PHYB involved in controlling hypocotyl elongation in increased concentration of BL whereas phyBdet2 double mutant just partially rescue to phyB in white and red light indicated the involvement of BRs in PHYB regulated cell elongation. BRs regulated hypocotyl growth was delayed by BAP, a cytokinin treatment but inhibitory effects of BAPs on hypocotyl growth was slightly recovered by BL. The result indicated that the mode of action of BR and cytokinin is independent or sequential in the downstream light-regulated response control on hypocotyl elongation and also light modulated the action of BR and cytokinin in some extent.