when the ph outside the cells is maintained below that of the cytoplasm ( ph 7 ) , auxin can be accumulated by the cells : in the initial phase of uptake , the direction of the auxin concentration gradient allows both passive carrier-mediated anion influx ( inhibited by 2,4d ) and a passive diffusion of undissociated acid molecules into the cells .
C0010834
cytoplasm
C0007634
cells