CHARACTERISTICS AND GROWTH-KINETICS OF ADVENTITIOUS ROOTS EMERGING OUT OF CELL AGGREGATES DERIVED FROM HORSERADISH HAIRY ROOTS

The effect of NAA (1-naphthaleneacetic acid) treatment on emergence of adventitious roots was examined in the process of root regeneration u sing cell aggregates derived from horseradish hairy roots. The number of emerging roots was significantly larger from those cell aggregates with increasing amounts of NAA absorbed by the cells. The cell aggrega tes with absorbed NAA of 11.3 to 17.1 x 10(-3) kg/kg-dry cells formed 3.4 to 3.7 x 10(5) roots per M2-aggregate surface area during the cult ure period of 456 h, indicating an 8- to 9-fold increase over that of cell aggregates without the treatment. The large number of available r oots emerging from cell aggregates with the NAA treatment consequently led to enhanced rates of root growth and sugar consumption in a batch culture for root regeneration. The kinetic behavior of root regenerat ion culture was described successfully on the basis of a model of bran ching root growth.