What is the formula of the DPD for withered (shrank) plant cells? How is that situation possible?
Ans) Withered plant cells are those that shrank because of loss of water by evaporation without enough replacement. In this situation the cell membrane retracts and detaches from the cell wall. The cell wall furthermore expands in length to stimulate the entrance of water making TP < 0. Since DPD = SF - TP and TP is negative (< 0) its formula becomes DPD = SF + |TP|.