Grafts et al. 



— 74 — 



Water in Plants 



ysis and full turgor. It is curved because the relation betwe^en osmotic 

 pressure and change in volume is hyperbolic (OP2 = OPi~), where 

 subscript 1 represents the initial state and 2 the subsequent state. 



JOQ 



1-04 



/.OS 



l/Z 



/■24 



""/To 



roz 104 ^06 /od flo 

 Relative Cell volume 



Fir 20 -Three forms of TP-volume curves for plant cells. A, curve for cells 

 havS waUs of htgh tensile strength. B and C, curves showing complex relations 

 between elasticity and tensile strength. 



Starting at the condition of limiting plasmolysis (relative cell volume 

 1.0) the DPD is high and equals the osmotic pressure of the cell contents 

 There is no turgor at this point. As water is taken up by the cell turgor 

 increases due to' the opposing force which the cell wall exerts on the cell 

 contents. 



