• Applied Biological Chemistry
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• v.40 no.4
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• pp.357-360
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• 1997

The biological activity of monoglycerides, diglycerides, triglycerides and free fatty acids were investigated by the rice inclination test that is specific bioassay for brassinosteroids. The experimental results revealed that some diglycerides, triglycerides and free fatty acids as well as monoglycerides showed positive response. ${\alpha}-Monoolein$ and diolein as active principles showed higher activity than indole-3-acetic acid at the same concentration. From the results, it can be confirmed that the active principles are related to olein which especially have a high activity.

• Applied Biological Chemistry
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• v.33 no.4
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• pp.307-314
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• 1990

Brassinosteroid-like substances in two japonica type Korean rices were investigated. The extracts from the shoots at the maximum tillering stage were purified by solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 chromatography, charcoal adsorption chromatography, preparative TLC, Bondesil chromatography and HPLC of normal phase and reverse phase, successively. Biological activity of each purification step were monitored by the rice lamina inclination test. Two cultivars tested in this experiment produced brassinosteroids and endogenous brassinosteroids showing similiarity between two cultivars.

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