Journal Article

FZJ-2022-05811

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Stomatal conductance tracks soil-to-leaf hydraulic conductance in faba bean and maize during soil drying

Müllers, Y.FZJ* ; Postma, J. A.FZJ* ; Poorter, H.FZJ* ; van Dusschoten, D. (Corresponding author)FZJ*

2022
Oxford University Press Oxford

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Please use a persistent id in citations: http://hdl.handle.net/2128/33173  doi:10.1093/plphys/kiac422

Abstract: Although regulation of stomatal conductance is widely assumed to be the most important plant response to soil drying, the picture is incomplete when hydraulic conductance from soil to the leaf, upstream of the stomata, is not considered. Here, we investigated to what extent soil drying reduces the conductance between soil and leaf, whether this reduction differs between species, how it affects stomatal regulation, and where in the hydraulic pathway it occurs. To this end, we noninvasively and continuously measured the total root water uptake rate, soil water potential, leaf water potential, and stomatal conductance of 4-week-old, pot-grown maize (Zea mays) and faba bean (Vicia faba) plants during 4 days of water restriction. In both species, the soil–plant conductance, excluding stomatal conductance, declined exponentially with soil drying and was reduced to 50% above a soil water potential of −0.1 MPa, which is far from the permanent wilting point. This loss of conductance has immediate consequences for leaf water potential and the associated stomatal regulation. Both stomatal conductance and soil–plant conductance declined at a higher rate in faba bean than in maize. Estimations of the water potential at the root surface and an incomplete recovery 22 h after rewatering indicate that the loss of conductance, at least partly, occurred inside the plants, for example, through root suberization or altered aquaporin gene expression. Our findings suggest that differences in the stomatal sensitivity among plant species are partly explained by the sensitivity of root hydraulic conductance to soil drying.

Keyword(s): Biology (2nd)

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Contributing Institute(s):

1. Pflanzenwissenschaften (IBG-2)

Research Program(s):

1. 2171 - Biological and environmental resources for sustainable use (POF4-217) (POF4-217)

Appears in the scientific report 2022

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Database coverage:
; ; ; BIOSIS Previews ; Biological Abstracts ; Clarivate Analytics Master Journal List ; Current Contents - Agriculture, Biology and Environmental Sciences ; Current Contents - Life Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; National-Konsortium ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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