Wolfram Hartung

TL;DR: It is proposed that the activation of inactive ABA pools by polymerized AtBG1 is a mechanism by which plants rapidly adjust ABA levels and respond to changing environmental cues.

TL;DR: It is shown that guard cells possess the entire ABA biosynthesis pathway and that it appears upregulated by positive feedback by ABA, highlighting the primacy of abscisic acid (ABA) in the stomatal response to drying air.

TL;DR: It is concluded that, by regulating the extent of apoplastic barriers and their chemical composition, plants can effectively regulate the uptake or loss of water and solutes.

TL;DR: Evidence is reviewed for a variety of long-distance signaling pathways involving hormones and nutrient ions moving in the xylem sap that allow regulation of plant growth, development and functioning, and particularly shoot water status, as distinct from stress lesions in growth and other processes as a reaction to perturbations such as soil drying.

TL;DR: The significance of reflection coefficients (sigma(ABA), permeability coefficients of membranes (P(S)(ABA)) and apoplastic barriers for ABA is discussed and the factors that modify the intensity of the ABA signal in the xylem are of particular interest.