Chlorogenic Acid Is Essential For Root Hair Formation In The Lettuce Seedlings.

Abstract

Low pH condition (pH4) induced root hair formation in the lettuce seedlings. Decapitation of shoot inhibited root hair formation. Root hair formation in isolated roots was recovered by addition of shoots water extracts. These results suggested that shoots contained some substances those were necessary for root hair formation. Addition of cytokinin could induce root hair formation in isolated roots. Behavior of the active substance in water extracts on C₁₈ Sep-Pak column differed from that of cytokinin. 3-O-caffeoylqunic acid (chlorogenic acid, CGA) was identified as the primarily active substance by HPLC isolation and LC-MS, NMR analysis. Application of 10^-5M CGA could induce root hair formation in both isolated roots at pH4 and intact plants at pH6. The content of CGA in the isolated roots was one forth of the intact seedlings root in pH4 medium. These data suggested that CGA was essential for root hair formation in lettuce seedlings.