Water potential wilting

As a consequence of the general reduction in metabolic activity, a significant reduction in the net photosynthetic rate, chlorophyll a and b contents (with an increase in chlorophyll alb ratio), and in the efficiency of water use and intrinsic water use were reported [67]. Furthermore, the decreased leaf water potentials cause visible wilting, having as a consequence an increase in the ABA concentration in the shoots. Different crop species have specific responses to hypoxia. 

In the majority of crop plants that have been studied proline accumulation in leaf tissue occurs only in response to severe water stress and is usually accompanied by visible wilting. A reduction in leaf water potentials to —10... 

Also the plants are able to use only the portion of water which is in the pF range below 4.2 4.5. This limiting value of the potential coincides with the so-called wilting point, for the osmotic apparatus of most cultivated plants is incapable to suck more strongly bound water from the soil. 

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