English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In Amazing numbers in biology, Flindt reports a giant, 128 meter-talleucalyptus, and a 135 meter-tall sequoia. However, the explanation of themaximum altitude of the crude sap ascent and consequently the main reason ofthe maximum size that trees can reach is not well understood. According to treespecies, the crude sap is driven in xylem microtubes with diameters rangingbetween 50 and 400 micrometers. The sap contains diluted salts but its physicalproperties are roughly those of water; consequently, hydrodynamic, capillarityand osmotic pressure yield a crude sap ascent of a few tens of meters only.Today, we can propound a new understanding of the ascent of sap to the top ofvery tall trees thanks to a new comparison between experiments associated withthe cohesion-tension theory and the disjoining pressure concept. Here we showthat the pressure in the water-storing tracheids of leaves can be stronglynegative whereas the pressure in the xylem microtubes of stems may remainpositive when, at high level, inhomogeneous liquid nanolayers wet the xylemwalls of microtubes. The nanofluidic model of crude sap in tall trees disclosesa stable sap layer up to an altitude where the pancake layer thickness coexistswith the dry xylem wall and corresponds to the maximum size of tallest trees.In very thin layers, sap flows are widely more significant than those obtainedwith classical Navier-Stokes models and consequently are able to refillstomatic cells when phloem embolisms supervene. These results drop an inklingthat the disjoining pressure is an efficient tool to study biological liquidsin contact with substrates at a nanoscale range.

The nanofluidics can explain ascent of water in tallest trees