Abstract
Both ion fluxes and changes of cytosolic pH take an active part in the signal transduction of different environmental stimuli. Here we studied the anoxia-induced alteration of cytosolic K+ concentration, [K+]cyt, and cytosolic pH, pHcyt, in rice and wheat, plants with different tolerances to hypoxia. The [K+]cyt and pHcyt were measured by fluorescence microscopy in single leaf mesophyll protoplasts loaded with the fluorescent potassium-binding dye PBFI-AM and the pH-sensitive probe BCECF-AM, respectively. Anoxic treatment caused an efflux of K+ from protoplasts of both plants after a lag-period of 300–450 s. The [K+]cyt decrease was blocked by tetraethylammonium (1 mM, 30 min pre-treatment) suggesting the involvement of plasma membrane voltage-gated K+ channels. The protoplasts of rice (a hypoxia-tolerant plant) reacted upon anoxia with a higher amplitude of the [K+]cyt drop. There was a simultaneous anoxia-dependent cytosolic acidification of protoplasts of both plants. The decrease of pHcyt was slower in wheat (a hypoxia-sensitive plant) while in rice protoplasts it was rapid and partially reversible. Ion fluxes between the roots of intact seedlings and nutrient solutions were monitored by ion-selective electrodes and revealed significant anoxia-induced acidification and potassium leakage that were inhibited by tetraethylammonium. The K+ efflux from rice was more distinct and reversible upon reoxygenation when compared with wheat seedlings.
Highlights
A wide range of signal perception and transduction systems in plant cells is responsible for distinguishing and triggering a correct adaptive response [1,2]
Ion fluxes between the roots of intact seedlings and nutrient solutions were monitored by ion-selective electrodes and revealed significant anoxia-induced acidification and potassium leakage that were inhibited by tetraethylammonium
Earlier we provided a comparison of calcium signaling during anoxia in two well-known agricultural plants such as rice and wheat, which differ in tolerance to oxygen limitation [35]
Summary
A wide range of signal perception and transduction systems in plant cells is responsible for distinguishing and triggering a correct adaptive response [1,2]. Plant cells carefully maintain a low Ca2+ concentration in the cytosol and a significant gradient between the cell wall and a number of organelles This balance is actively regulated by a variety of membrane transport systems (recently reviewed in [6]). A signaling role of potassium is well documented for salt stress [18] Oxygen deficiency is another stress factor that affects K+ efflux and causes severe damage to plant organisms [26,27,28,29,30]. We investigated the ion changes after reoxygenation as well It is of special interest how proton and Ca2+ accumulation inside cells and active potassium efflux would reflect processes during long-time stress applications and regulate the ion exchange with an external medium
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
