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Abstract Detail

Wood: Biology of a Living Tissue

Steppe, Kathy [1].

The role of living cells in water transport and storage.

Living cells in xylem and phloem play a vital role in the plant’s functioning. A central quantity that makes them so essential is turgor. Turgor, or the positive pressure in living cells, intimately links tissue water and carbon balances through osmotic pressure. It is also the exclusive driving force for cell wall expansion and growth, and controls cell formation, deposition and assembly of new cell wall material. Understanding dynamics in turgor is thus critical to understand growth and drought physiology of plants. Turgor not only decreases with intensified drought as predicted by the Höfler diagram, but also changes dynamically within a day, because living cells act as internal water reserves that are depleted daily and subsequently replenished overnight to overcome temporal imbalances between water loss by leaf transpiration and water uptake by roots. Water released from living cells serves as an important buffering system (hydraulic capacitance) for smoothing abrupt changes in xylem water potential. Vulnerability of a plant to drought stress thus hinges on the interplay between its sensitivity to cavitation and its hydraulic capacitance.
And then there are these green living cells beneath the bark that are often ignored in the international debate on drought and mortality mechanisms, but which may have far-reaching implication of how plants cope with water deficit. Refixation of respired CO2 by photosynthesis in these chlorophyll-containing cells provides carbon locally, which has been emphasized to become increasingly important under drought, when supply of photosynthate from leaves dwindles due to stomatal closure and impaired phloem translocation.
The goal of this talk is to provide an overview of the fascinating new findings about the role of living cells in water transport and storage, and its contribution toward maintenance of the functional integrity of xylem in plants.

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1 - Ghent University, Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Coupure links 653, Ghent, B-9000, Belgium

water relations
hydraulic capacitance
woody tissue photosynthesis

Presentation Type: Symposium Presentation
Session: SY09, Wood: Biology of a Living Tissue
Location: Oglethrope Auditorium/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 8:45 AM
Number: SY09003
Abstract ID:280
Candidate for Awards:None

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