preprints.org > biology and life sciences > biochemistry and molecular biology > doi: 10.20944/preprints202405.1690.v1

Preprint Review Version 1 Preserved in Portico This version is not peer-reviewed

Version 1 : Received: 26 May 2024 / Approved: 27 May 2024 / Online: 27 May 2024 (06:38:06 CEST)

The power of movement in plants” by Charles Darwin details many examples of oscillatory growth exemplified more recently at the single cell level by pollen tube tip oscillations and associated ion fluxes, particularly Ca²⁺and H⁺. That implies an underlying growth oscillator based on the recent discovery that classical AGPs bind Ca²⁺ at the cell surface. The juxtaposition of AGPs with three other components embedded in the plasma membrane is evidence of a Ca²⁺ cycle that generates cytosolic Ca²⁺. It involves Ca²⁺ channels, auxin efflux “PIN” proteins and an auxin-activated proton pump that dissociates AGP-Ca²⁺ on demand. While the apparent simplicity of this system satisfies Occam’s Razor its hypothetical role as a global growth oscillator demands rigorous experimental appraisal. The wide ramifications extend from pollen tubes to stomatal guard cells. Stomata act as crucial components of a water hypercycle that contributes to homeostasis of a warming planet by regulating evaporative cooling, reflective cloud cover generated by vast forests and the high albedo of snow-capped mountains including polar ice-caps . The Gaia hypothesis of James Lovelock and Lynn Margulis is a brilliant metaphor.

climate change; stomata; growth oscillator; arabinogalactan protein; Gaia hypothesis

Biology and Life Sciences, Biochemistry and Molecular Biology

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