HAL Id: hal-01512113
https://hal.archives-ouvertes.fr/hal-01512113
Submitted on 21 Apr 2017
HAL is a multi-disciplinary open access
archive for the deposit and dissemination of
sci-entific research documents, whether they are
pub-lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d’enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.
Impact of water stress-induced embolism on bud
survival in Populus nigra sprouts
Tete Severien Barigah, Marc Bonhomme, David Lopez, Amidou Traore,
Jean-Stéphane Venisse, Hervé Cochard, Eric Badel
To cite this version:
Tete Severien Barigah, Marc Bonhomme, David Lopez, Amidou Traore, Jean-Stéphane Venisse, et
al.. Impact of water stress-induced embolism on bud survival in Populus nigra sprouts. International
Symposium on Wood Structure in Plant Biology and Ecology, Apr 2013, Naples, Italy. 2013.
�hal-01512113�
Aims
Impact of water stress-induced embolism on bud survival in Populus nigra L. sprouts
T.S. Barigah
1,2, M. Bonhomme
1,2, D. Lopez
1,2, A. Traoré
3, J.-S. Venisse
1,2, H. Cochard
1,2and E. Badel
1,2tete.barigah@clermont.inra.fr
1INRA, UMR 547 PIAF, 5 chemin de Beaulieu, F-63039 Clermont-Ferrand Cedex 02, France
2Clermont Université, Université Blaise-Pascal, UMR 547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France 3INRA, UR 0370 QuaPA, F-63122 Saint Genès Champanelle
Material and methods
Results and conclusions
The aims of this study were to collect information on how the buds are hydraulically supplied from the bearer stem and on the impact of water stress on bud survival.
We submitted young Populus nigra potted trees to water stress for several weeks and carried out measurements of bud metabolic activity, transcript expression of aquaporins, xylem water potential of the bearer stem together with local water status within the bud and tissues in the bearer shoot node.
We found that bud respiration rate was closely correlated to its water content and decreased concomitantly in buds and their surrounding bearer tissues. Modulation of aquaporin expressions (PIP, TIP and XIP subfamilies) seemed to be linked to water movements in living cells. Both buds and trees died simultaneously beyond a threshold water content and respiration rate. Nuclear magnetic resonance (NMR) imaging provided relevant local information about the water reservoirs in the stem, their dynamics and their interconnections (Barigah et al, 2013). This study provides insights into a possible water distribution between connected tissues within water stressed plants, hydraulic trade-offs between the meristematic zone integrity, and the hydration of the bud and its surrounding tissues.
Patterns of predawn leaf water potential (a), percent loss of conductivity of the stem (b), bud heat rate and respiration rate (c) and normalized proton density (d) over the sampling periods of time. Leaf water potential was not available after leaf shedding.
Three-dimensional MRI mapping of the shoot segments containing the bud. Bright discs show the capillary glass filled with doped water that allows the grey level calibration. At the terminal drought stage, the cambium remained hydrated, while the bud was already dry and dead (resolution:39µm).
Cytological observations (x 10) of the stem anatomy. Transverse slice (25 µm thick) shows the large connection between the bud and parenchyma tissue that surrounds the pith.
Three-dimensional visualization of the normalized proton density (MRI measurements) in the bud and the stem during a water stress event (4 weeks). The proton density reflects the quantity of water contained in the tissues. These observations enlighten a large hydraulic connection between the bud and the parenchyma tissue that surrounds the pith and the connection of the bud with the cambial area. The cambium was the most highly hydrated tissue (resolution: 39µm).
Barigah TS, M Bonhomme, D Lopez, A Traore, M Douris, J-S Venisse, H Cochard, E Badel, 2013 - Modulation of bud survival in Populus nigra sprouts in response to water stress-induced embolism. Tree Physiology, 33(3): 261-274.
Reference
Real-time PCR cycler
Monitoring of mRNA accumulation of PIP, TIP and XIP aquaporin subfamilies in bark, wood and buds. Only PIP1;1 out of the 32 expressed aquaporin genes did not show significant differential expression (water stressed vs well-watered control) after 28 days of water stress.
Bud survival is vital to sustain tree growth across seasons but the lack of water supply may induce weakness that could lead to tree death.
Introduction
Young potted poplar trees Time Domain Reflectometer MRI scanner Pressure chamber Xylem Embolism Meter Microcalorimeter
ΨΨΨΨp , M P a -3 -2 -1 0 B u d r e s p ir a ti o n , n m o lCO 2 g -1 s -1 0 10 20 30 H e a t ra te , µ W m g -1 0 2 4 6 8 10 Respiration rate Heat rate
Water stress duration, Day
0 10 20 30 40 50 60 N o rm a li z e d p ro to n d e n s it y 0.0 0.1 0.2 0.3 Bark Cambium Xylem Pith Bud P e rc e n t L o s s C o n d u c ti v it y , % 0 20 40 60 80 100 a b c d f= 100.5/(1+exp(-(x-16.3)/5.0)); r2=0.92, p = 0.0017 p = 0.0032 a b b b 0 10 20 30 40 50 60 70 80 100 90 A rb it ra ry u n it s Bud Wood Bark ab PIP1;1 0.52±0.21 -0.55±0.72 0.39±0.15 aabb bab bab TIP1;5 0.49±0.11 1.69±0.88 -0.26±0.18 a ab ab PIP2;1 2.37±0.32 0.52±0.48 1.15±0.11 c bab c a d XIP3;2 --3.40±0.88 -b a Bud control Bud drought Wood control Wood drought Bark control Bark drought No detectable expression F o ld c h a n g e 0 10 20 30 40 50 60 70 80 100 90 A rb it ra ry u n it s Bud Wood Bark ab PIP1;1 0.52±0.21 -0.55±0.72 0.39±0.15 aabb bab bab TIP1;5 0.49±0.11 1.69±0.88 -0.26±0.18 a ab ab PIP2;1 2.37±0.32 0.52±0.48 1.15±0.11 c bab c a d XIP3;2 --3.40±0.88 -b a Bud control Bud drought Wood control Wood drought Bark control Bark drought No detectable expression F o ld c h a n g e
