title: Hydrolase treatments help unravel the function of intervessel pits in xylem hydraulics.
abstract: Intervessel pits are structures that play a key role in the efficiency and safety functions of xylem hydraulics. However, little is known about the components of the pit membrane (PM) and their role in hydraulic functions, especially in resistance to cavitation. We tested the effect of commercial chemicals including a cellulase, a hemicellulase, a pectolyase, a proteinase and DTT on xylem hydraulic properties: vulnerability to cavitation (VC) and conductance. The effects were tested on branch segments from Fagus sylvatica (where the effects on pit structure were analyzed using TEM) and Populus tremula. Cellulose hydrolysis resulted in a sharp increase in VC and a significant increase in conductance, related to complete breakdown of the PM. Pectin hydrolysis also induced a sharp increase in VC but with no effect on conductance or pit structure observable by TEM. The other treatments with hemicellulase, proteinase or DTT showed no effect. This study brings evidence that cellulose and pectins are critical components underpinning VC, and that PM components may play distinct roles in the xylem hydraulic safety and efficiency.
authors: INRA, UMR547 PIAF, 5 Chemin de Beaulieu, 63039, Clermont-Ferrand, Cedex 02, France; Clermont Université, Université Blaise-Pascal, UMR547 PIAF, BP 10448, 63000, Clermont-Ferrand, France.
authors: Anaïs
authors: A
authors: Dusotoit-Coucaud
authors: Nicole
authors: N
authors: Brunel
authors: Aude
authors: A
authors: Tixier
authors: Hervé
authors: H
authors: Cochard
authors: Stéphane
authors: S
authors: Herbette
mesh_terms: D001692:Biological Transport / Q000187:drug effects; D002482:Cellulose / Q000378:metabolism; D029964:Fagus / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism / Q000494:pharmacology; D006867:Hydrolases / Q000378:metabolism* / Q000494:pharmacology; D006868:Hydrolysis; D046529:Microscopy, Electron, Transmission; D010368:Pectins / Q000378:metabolism; D018514:Plant Structures / Q000378:metabolism* / Q000648:ultrastructure; D011133:Polysaccharide-Lyases / Q000378:metabolism / Q000494:pharmacology; D032107:Populus / Q000378:metabolism; D011312:Pressure; D014867:Water / Q000378:metabolism*; D052584:Xylem / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D014867:Water; D010368:Pectins; D002482:Cellulose; D006867:Hydrolases; D006026:Glycoside Hydrolases; C023305:hemicellulase; D011133:Polysaccharide-Lyases; C027349:pectin lyase