Stomatal factors and vulnerability of stem xylem to cavitation in poplars

The relationships between the vulnerability of stem xylem to cavitation, stomatal conductance, stomatal density, and leaf and stem water potential were examined in six hybrid poplar (P38P38, Walker, Okanese, Northwest, Assiniboine and Berlin) and balsam poplar (Populus balsamifera) clones. Stem xyle...

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Bibliographic Details
Published in:Physiologia plantarum 2011-10, Vol.143 (2), p.154-165
Main Authors: Arango-Velez, Adriana, Zwiazek, Janusz J., Thomas, Barb R., Tyree, Melvin T.
Format: Article
Language:English
Subjects:
Biological and medical sciences
Droughts
Fundamental and applied biological sciences. Psychology
Plant Leaves - metabolism
Plant Leaves - physiology
Plant physiology and development
Plant Stems - metabolism
Plant Stems - physiology
Plant Stomata - metabolism
Plant Stomata - physiology
Plant Transpiration
Populus - metabolism
Populus - physiology
Soil - chemistry
Species Specificity
Stress, Physiological
Water - metabolism
Xylem - metabolism
Xylem - physiology
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Summary:The relationships between the vulnerability of stem xylem to cavitation, stomatal conductance, stomatal density, and leaf and stem water potential were examined in six hybrid poplar (P38P38, Walker, Okanese, Northwest, Assiniboine and Berlin) and balsam poplar (Populus balsamifera) clones. Stem xylem cavitation resistance was examined with the Cavitron technique in well‐watered plants grown in the greenhouse. To investigate stomatal responses to drought, plants were subjected to drought stress by withholding watering for 5 (mild drought) and 7 (severe drought) days and to stress recovery by rewatering severely stressed plants for 30 min and 2 days. The clones varied in stomatal sensitivity to drought and vulnerability to stem xylem cavitation. P38P38 reduced stomatal conductance in response to mild stress while the balsam poplar clone maintained high leaf stomatal conductance under more severe drought stress conditions. Differences between the severely stressed clones were also observed in leaf water potentials with no or relatively small decreases in Assiniboine, P38P38, Okanese and Walker. Vulnerability to drought‐induced stem xylem embolism revealed that balsam poplar and Northwest clones reached loss of conductivity at lower stem water potentials compared with the remaining clones. There was a strong link between stem xylem resistance to cavitation and stomatal responsiveness to drought stress in balsam poplar and P38P38. However, the differences in stomatal responsiveness to mild drought suggest that other drought‐resistant strategies may also play a key role in some clones of poplars exposed to drought stress.
ISSN:0031-9317
1399-3054
DOI:10.1111/j.1399-3054.2011.01489.x