Proton extrusion by Leaf Discs ofVicia faba L.: Influence of inhibitors and phytohormones on H+ extrusion†

Petzold, U.; Dahse, I.; Jacob, Preeti T.

doi:10.1007/bf02878203

Cited by 2 publications

(4 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…WL causes leaf cells to acidify the wall solution (3,15,24). The fact that vanadate (3,15) and ATP synthesis inhibitors (5, 15) block this acidification indicates that it is mediated by the PM H+-ATPase.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization and Effect of Light on the Plasma Membrane H⁺-ATPase of Bean Leaves

Linnemeyer¹,

Volkenburgh²,

Cleland³

1990

Plant Physiol.

View full text Add to dashboard Cite

Proton excretion from bean (Phaseolus vulgaris L.) leaf cells is increased by bright white light. To test whether this could be due, at least in part, to an increase in plasma membrane (PM) ATPase activity, PM vesicles were isolated from primary leaves by phase partitioning and used to characterize PM ATPase activity and changes in response to light. ATPase activity was characterized as magnesium ion dependent, vanadate sensitive, and slightly stimulated by potassium chloride. The pH optimum was 6.5, the Km was approximately 0.30 millimolar ATP, and the activity was about 60% latent. PM vesicles were prepared from leaves of plants grown for 11 days in dim red light (growing slowly) or grown for 10 days in dim red light and then transferred to bright white-light for I day (growing rapidly). For both light treatments, ATPase specific activity was approximately 600 to 700 nanomoles per milligram protein per minute, and the latency, Km, and sensitivity to potassium chloride were also similar. PM vesicles from plants grown in complete darkness, however, exhibited a twofold greater specific activity. We conclude that the promotion of leaf growth and proton excretion by bright white light is not due to an increase in ATPase specific activity. Light does influence ATPase activity, however, both dim red light and bright white light decreased the ATPase specific activity by nearly 50% as compared with dark-grown leaves. environment and hyperpolarizing the membrane potential (19). The resulting electrochemical gradient facilitates the uptake of ions, amino acids, and sugars (19). The lightinduced proton excretion from bean leaf cells is presumed to be mediated by the PM H+-ATPase. Light might stimulate H+ excretion in at least four ways: (a) by increasing the supply of substrate (ATP); (b) by altering the cytoplasmic pH; (c) by increasing the activity of the existing enzyme (e.g. by phosphorylation of the enzyme); or (d) by increasing the amount of H+-ATPase in the PM. Both of the latter two mechanisms should result in an enhanced activity of the PM ATPase in isolated PM vesicles.Although the PM ATPase from roots and stems has been extensively studied (19), the enzyme in leaves has received only limited attention. In the study reported here, we have used the aqueous phase partitioning method (7) to isolate highly purified PM vesicles from the primary leaves of Phaseolus vulgaris L. and have characterized the ATPase in these vesicles. We have used this system to show that while light promotes the ATPase-mediated proton excretion (24), a lightinduced change in ATPase activity cannot explain this effect. MATERIALS AND METHODS

show abstract

Section: Discussionmentioning

confidence: 99%

“…The fact that vanadate (3,15) and ATP synthesis inhibitors (5, 15) block this acidification indicates that it is mediated by the PM H+-ATPase. The light-induced hyperpolarization of the membrane potential is consistent with this concept (16).…”

Section: Discussionmentioning

confidence: 99%

Characterization and Effect of Light on the Plasma Membrane H⁺-ATPase of Bean Leaves

Linnemeyer¹,

Volkenburgh²,

Cleland³

1990

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…6) suggests that photosynthesis plays an im- [Vol. Experiments performed by Petzold and Dahse (1988) using Vida faba leaf discs suggest that this role involves the supply of energy for the pumping of protons. Experiments performed by Petzold and Dahse (1988) using Vida faba leaf discs suggest that this role involves the supply of energy for the pumping of protons.…”

Section: Discussionmentioning

confidence: 99%

“…77 portant role in this ATPase-driven process. Experiments performed by Petzold and Dahse (1988) using Vida faba leaf discs suggest that this role involves the supply of energy for the pumping of protons. Substitution of 5 mM sucrose for light does not fully compensate for the drop in proton extrusion.…”

Section: Discussionmentioning

confidence: 99%

Translocation in Polytrichum Commune (Bryophyta). Iii. Loading of Sugars in Source Leaves

Thomas

Grethlein

Perou

et al. 1990

American J of Botany

View full text Add to dashboard Cite

Polytrichum commune, the common hair‐cap moss, possesses a system of long‐distance food‐conducting cells that can be traced from leaves into stems and down through underground rhizomes. Cytochemical analysis indicates that high adenosine triphosphatase activity is associated with the membranes of sugar‐conducting deuter cells in Polytrichum leaves. Incipient plasmolysis determinations reveal high solute concentrations of leaf deuters. These two lines of evidence suggest that long‐distance transport of photosynthate is initiated in this species by a process analogous to phloem loading of minor veins in leaves of flowering plants. Two sets of experimental observations suggest that sugar loading in Polytrichum is coupled with the transport of protons: the moderating effects of N‐ethylmaleimide, p‐chloromercuribenzenesulfonic acid, sodium orthovanadate, and fusicoccin on labeled sucrose uptake (as determined by liquid scintillation techniques), and correlated effects on acid flux from isolated leaves (as determined by computer‐aided titrimetry).

show abstract

Proton extrusion by Leaf Discs ofVicia faba L.: Influence of inhibitors and phytohormones on H+ extrusion†

Cited by 2 publications

References 24 publications

Characterization and Effect of Light on the Plasma Membrane H⁺-ATPase of Bean Leaves

Characterization and Effect of Light on the Plasma Membrane H⁺-ATPase of Bean Leaves

Translocation in Polytrichum Commune (Bryophyta). Iii. Loading of Sugars in Source Leaves

Contact Info

Product

Resources

About

Proton extrusion by Leaf Discs ofVicia faba L.: Influence of inhibitors and phytohormones on H+ extrusion†

Cited by 2 publications

References 24 publications

Characterization and Effect of Light on the Plasma Membrane H+-ATPase of Bean Leaves

Characterization and Effect of Light on the Plasma Membrane H+-ATPase of Bean Leaves

Translocation in Polytrichum Commune (Bryophyta). Iii. Loading of Sugars in Source Leaves

Contact Info

Product

Resources

About

Characterization and Effect of Light on the Plasma Membrane H⁺-ATPase of Bean Leaves

Characterization and Effect of Light on the Plasma Membrane H⁺-ATPase of Bean Leaves