Fig. 3.

Scheme of some root responses to osmotic-induced dehydration. Early and delayed responses are deduced from experiments applying osmotic stress and comprise events occurring within minutes (early) to several days (delayed) (data from Aroca et al., 2012). Dehydration is perceived by putative osmosensors [AtHKT1, CRE, AQPs (a sensor role of AQPs; Hill et al., 2004)]. AtHKT1 and CRE are analogous to the yeast osmosensor SLN1 activating the MAPK cascade. Decreased root hydraulic conductance due to reduced AQP activity (phosphorylation/dephosphorylation events) is an early response to protect cells from dehydration. The MAPK cascade may be implicated in root osmotic adjustment under water deficit, with plasma membrane AQPs genes being induced after root osmotic adjustment (delayed response). Lines and arrows are as in Fig. 1 legend.