Responses of Mentha suspension-cultured cells to 2,4-dichlorophenoxyaceticacid and accumulation of esterified phenolic acids in their cell walls

Two distinct types of cell growth of suspension-cultured Mentha were formed when the cells maintained in the medium containing 1000 mu gl(-1) 2,4-D we re subcultured into different 2,4-D concentrations. Few cell elongation of Mentha (average cell length: 34 similar to 40 mu m) was observed after divi sion in the medium containing 1 similar to 200 mu gl(-1) 2,4-D; and signifi cant cell elongation (average cell length: 95 similar to 130 mu m) was obse rved after cell division in the medium containing 500 similar to 2000 mu gl (-1) 2,4-D. A close correlation between culture medium and water content in the cells indicated that 2,4-D promoted cell elongation by water uptake. A mounts of phenolic acid in cell walls were much higher in unelongated cell walls than in elongated ones during the cultivation, and there was a close correlation between the amounts and the level of PAL activity in elongated and unelongated cells. However, there was no significant difference in cell wall components and its neutral sugar composition between elongated and un elongated cells.