Unformatted text preview: Root tip placed horizontally Migration of statoliths as root curves downward Statoliths at cell base Model of statolith movement when cells are rotated • One explanation for statolith movement is that hydrostatic pressure differences exerted by the protoplast (which includes the amyloplasts) trigger cell wall expansion. • Another explanation is that Ca + + channels in the plasma membrane that connect to the cytoskeleton and to the cell wall open in response to hydrostatic pressure changes in the membrane. Opening the channels would permit movement of Ca ++ that could trigger the signal transduction pathways needed to activate auxin for the promotion of the differential cell expansion....
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- Fall '09