Conservative water use under high evaporative demand associated with smaller root metaxylem and limited trans-membrane water transport in wheat

Rémy Schoppach, Diego Wauthelet, Linda Jeanguenin, Walid Sadok

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Efficient breeding of drought-tolerant wheat (Triticum spp.) genotypes requires identifying mechanisms underlying exceptional performances. Evidence indicates that the drought-tolerant breeding line RAC875 is water-use conservative, limiting its transpiration rate (TR) sensitivity to increasing vapour pressure deficit (VPD), thereby saving soil water moisture for later use. However, the physiological basis of the response remains unknown. The involvement of leaf and root developmental, anatomical and hydraulic features in regulating high-VPD, whole-plant TR was investigated on RAC875 and a drought-sensitive cultivar (Kukri) in 12 independent hydroponic and pot experiments. Leaf areas and stomatal densities were found to be identical between lines and de-rooted plants didn't exhibit differential TR responses to VPD or TR sensitivity to four aquaporin (AQP) inhibitors that included mercury chloride (HgCl2). However, intact plants exhibited a differential sensitivity to HgCl2 that was partially reversed by β-mercaptoethanol. Further, root hydraulic conductivity of RAC875 was found to be lower than Kukri's and root cross-sections of RAC875 had significantly smaller stele and central metaxylem diameters. These findings indicate that the water-conservation of RAC875 results from a root-based hydraulic restriction that requires potentially heritable functional and anatomical features. The study revealed links between anatomical and AQP-based processes in regulating TR under increasing evaporative demand.

Original languageEnglish (US)
Pages (from-to)257-269
Number of pages13
JournalFunctional Plant Biology
Volume41
Issue number3
DOIs
StatePublished - Feb 20 2014

Keywords

  • aquaporins
  • drought tolerance
  • hydraulic restriction
  • transpiration.

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