Identification of root hair inducing substance which was derived from shoot apex and analysis of the role of this substance in low pH induced root hair formatin.

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High density of root hairs were induced on a lettuce root when a lettuce seedling was cultured at pH 4.In this phenomenon, supply of unknown substance which should be derived form shoot apex was essential.In this study, identification and characterization of this substance was performed.At first, proper plant materials were determined.Not only young seedling but also aged grown plant contained this substance.Therefore, 1 month old grown seedlings were chosen as a starting materials.Next, extraction methods were investigated. Acetone extraction was about 30 times eWcientx to compare with water extraction.For the bioassay, tiny acrylic resin culturing wares were constructed.Activity of acetone extracts was not influenced by heat treatment(100 C, 10 mm).This results ggested that the active substance was heat stable.Result of solvent fractionation using water-ethyl acetate indicated that the substance was fractionated in water phase.Next, resultant of solvent fractionation was partially purified by C18 pre-column.When the substance was solved in pH6 water, the substance could not be adsorbed on the column.The substance solved in pH3 water could be adsorbed on the column, and eluted by 20% acetonitrile.Using anion exchange pre-column, the substance could be eluted in the acidic fraction.These results suggested that the substance should be a week organic acid.Advanced isolation of the acidic fraction by C18 column HPLC exhibited that the substance was isolated in the single peak at 18.5-21.5% acetonitrile fraction.