ABSTRACT
Many yield determining physiological processes in plants respond to water stress. Most of these processes are dynamic and their activities may fluctuate with time according to internal and external factors. Yield integrates many of these physiological processes in a complex way and it is, thus, difficult to interpret how do plants accumulate, combine, and display the everchanging and indefinite physiological processes over the entire life cycle of the crop. Moreover, as far as water stress is concerned, severity, duration, and timing of stress, as well as responses, which may take place after stress removal, and interaction between stress and other factors may be extremely variable. It would thus be very inconceivable, from a practical point of view, to study the response of physiological processes to the dynamic changes in plant water stress and accordingly conclude how the final yield will respond. The more pragmatic approach for determining the response of plant productivity to dynamic changes in water stress should thus be based directly on the yield or its components.
