Alterations of Intracellular pH in Response to Low Temperature Stresses

Abstract

In chilling-sensitive plants, the inactivation of the vacuolar H+-ATPase is one of the primary cellular events directly resulting from cold exposure. We demonstrate here that cold-induced inactivation of the proton translocating enzyme is closely linked to the rapid acidification of the cytoplasm and the concomitant alkalization of the vacuoles, suggesting an important role of the enzyme in maintaining homeostasis of the cellular pH in a cold environment. The stability of the vacuolar H+-ATPase to cold both in vivo and in vim is distinctly different between species sensitive and insensitive to cold. These findings provide further insight into the way in which the vacuolar H+-ATPase is involved in cold adaptation of plants. In addition, the temperature reduction and the concentration of the cytoplasm as a consequence of freeze-induced dehydration may also result in changes in the cellular pH. In fact, we demonstrate here that the cytoplasm is markedly acidified upon freezing; in particular, in cells of less hardy plants. Freeze-induced acidification is presumably due to changes in the physicochemical properties of the cytoplasm and the changes in the permeability of the vacuolar membrane both of which result from severe dehydration. The physiological significance of freeze-induced acidification of the cytoplasm is discussed.

Kinetics of net H+, Ca2+, K+, Na+, , and Cl– fluxes associated with post‐chilling recovery of plasma membrane transporters in Zea mays leaf and root tissues

“…There is much evidence in the literature that cold inactivation of H + transporting systems is among the most sensitive membrane‐transport processes, especially in chilling‐sensitive species (Kennedy and Gonsalves 1988, Yoshida 1991, 1994, Marschner 1995, Yoshida et al. 1999, Kasamo et al.…”

Effect of temperature on growth, proton extrusion and membrane potential in maize (Zea mays L.) coleoptile segments

“…7B). Several mechanisms, including decrease in H + pump activity or net H + and Ca 2+ uptake by plant tissues, have been suggested as explanations for membrane potential depolarization under cold stress (Minorsky 1989;Ding and Pickard 1993;Yoshida et al 1999;Shabala and Shabala 2002). However, the fact that net H + uptake took place at 108C (Fig.…”

Chilling and Freezing Stresses in Plants: Cellular Responses and Molecular Strategies for Adaptation

“…Recent data suggest that also the protein fraction and the lipid composition asymmetry of transmembrane bilayer could be involved in cold adaptation [19]. For instance, cold-induced changes have been reported in the lipid-protein ratio of thylakoid membranes, in the activity of plasma membrane H+-ATPase and in tonoplast enzymes [20][21][22]. At genomic level, stable genomic changes are inducible by environmental stresses.…”