This title appears in the Scientific Report :
2019
Old year rings may provide water storage capacity by cavitating first
Old year rings may provide water storage capacity by cavitating first
The sapwood of temperate trees comprises many year rings. Conduits in the current year ring commonly are assumed to conduct most flow. Those in older rings, conversely, are assumed to be less efficiently connected to new leaves, and may have become more susceptible to cavitation. We hypothesize that...
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Personal Name(s): | Windt, Carel (Corresponding author) |
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Contributing Institute: |
Pflanzenwissenschaften; IBG-2 |
Imprint: |
2019
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Conference: | XIM4 4th Xylem meeting Padua, Padua (Italy), 2019-09-25 - 2019-09-27 |
Document Type: |
Conference Presentation |
Research Program: |
Plant Science |
Publikationsportal JuSER |
The sapwood of temperate trees comprises many year rings. Conduits in the current year ring commonly are assumed to conduct most flow. Those in older rings, conversely, are assumed to be less efficiently connected to new leaves, and may have become more susceptible to cavitation. We hypothesize that older year rings thus will hold more dead-end conduits, conduct less flow and cavitate before the current year xylem does, releasing stored water. To test this hypothesis we used MRI relaxometry and flowmetry, utilizing both a traditional high field imager and a mobile, battery driven one. MRI cannot always resolve singular xylem conduits, especially if it is a mobile device. We here propose and demonstrate MRI methods to nonetheless detect water filled conduits and quantify the flow conducting area – or loss thereof. Large beech trees were exposed to drought. Initially, all xylem regions that contained water filled vessels also exhibited flow. Stagnant water in old or current year rings could not be detected. Cavitation did however start in the oldest year rings first, supporting our hypothesis. Observations in beech and spruce saplings confirmed this observation. However, release of water from old year rings did not appear to slow the spread of cavitation. |