TY  - JOUR
AU  - Levionnois, S.
AU  - Ziegler, C.
AU  - Jansen, S.
AU  - Calvet, E.
AU  - Coste, S.
AU  - Stahl, C.
AU  - Salmon, C.
AU  - Delzon, S.
AU  - Guichard, C.
AU  - Heuret, P.
PY  - 2020//
TI  - Vulnerability and hydraulic segmentations at the stem–leaf transition: coordination across Neotropical trees
T2  - New Phytol.
JO  - New Phytologist
SP  - 512
EP  - 524
VL  - 228
IS  - 2
PB  - Blackwell Publishing Ltd
KW  - drought-induced embolism resistance
KW  - hydraulic segmentation
KW  - leaf-specific conductivity
KW  - stem–leaf transition
KW  - tropical trees
KW  - vulnerability segmentation
KW  - air bubble
KW  - hydraulic conductivity
KW  - leaf
KW  - Neotropical Region
KW  - rainforest
KW  - tropical forest
KW  - vulnerability
KW  - xylem
N2  - Hydraulic segmentation at the stem–leaf transition predicts higher hydraulic resistance in leaves than in stems. Vulnerability segmentation, however, predicts lower embolism resistance in leaves. Both mechanisms should theoretically favour runaway embolism in leaves to preserve expensive organs such as stems, and should be tested for any potential coordination. We investigated the theoretical leaf-specific conductivity based on an anatomical approach to quantify the degree of hydraulic segmentation across 21 tropical rainforest tree species. Xylem resistance to embolism in stems (flow-centrifugation technique) and leaves (optical visualization method) was quantified to assess vulnerability segmentation. We found a pervasive hydraulic segmentation across species, but with a strong variability in the degree of segmentation. Despite a clear continuum in the degree of vulnerability segmentation, eight species showed a positive vulnerability segmentation (leaves less resistant to embolism than stems), whereas the remaining species studied exhibited a negative or no vulnerability segmentation. The degree of vulnerability segmentation was positively related to the degree of hydraulic segmentation, such that segmented species promote both mechanisms to hydraulically decouple leaf xylem from stem xylem. To what extent hydraulic and vulnerability segmentation determine drought resistance requires further integration of the leaf–stem transition at the whole-plant level, including both xylem and outer xylem tissue. © 2020 The Authors. New Phytologist © 2020 New Phytologist Trust
SN  - 0028646x (Issn)
UR  - http://dx.doi.org/10.1111/nph.16723
N1  - exported from refbase (http://php.ecofog.gf/refbase/show.php?record=952), last updated on Mon, 08 Feb 2021 11:15:39 -0300
ID  - Levionnois_etal2020
ER  -