Isolation of root hairs from seedlings of Pisum sativum. Identification of root hair specific proteins by in situ labeling

A procedure was developed which allows the large‐scale isolation of root hairs from seedlings of Pisum sativum. L. cvs. Kleine Rheinländerin and Rosa Krone. The method may yield up to 50 g fresh weight of root hairs per 3.104 seedlings. In a modified form considerable amounts of root hair material may be harvested, even after incubation of the roots in aqueous solutions. Thus, detailed biochemical studies on the root hair system have become feasible. The occurrence of specific proteins in membrane fractions of P. sativum root hairs was demonstrated as follows: Incubation of root hairs in situ with 3‐azidonaphthalene‐2,7‐disulfonate – a strongly anionic, photoactivated fluorescent marker – followed by gel electrophoresis of membrane fractions showed the presence of root‐hair specific proteins which, since the system was intact, suggests that they are on the outer surface of the cells.