Plants are constantly tailoring their responses to current
environmental conditions via a complex array of chemical
regulators that integrate developmental and physiological programs
across the plant body. Environmental stimuli are often
highly localized in nature, but the subsequent plant response is
often elicited throughout the entire organism. For example, soil
is a highly heterogeneous environment and the root encounters
stimuli that are presented in a patchy manner. Thus, factors including
dry or waterlogged regions of the soil, variations in the
osmotic environment, and stresses such as elevated levels of salt
are all likely to be encountered locally by individual root tips, but
the information may have to be acted on by the plant as a whole.