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Drought stress, growth and nonstructural carbohydrate dynamics of pine trees in a semi-arid forest.

  • Klein T Institute of Botany, University of Basel, Basel, Switzerland Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel tamir.klein@unibas.ch.
  • Hoch G Institute of Botany, University of Basel, Basel, Switzerland.
  • Yakir D Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel.
  • Körner C Institute of Botany, University of Basel, Basel, Switzerland.
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  • 2014-09-05
Published in:
  • Tree physiology. - 2014
carbon balance
carbon transport
phloem
tree rings
Carbohydrate Metabolism
Desert Climate
Droughts
Israel
Pinus
Plant Roots
Plant Shoots
Stress, Physiological
English In trees exposed to prolonged drought, both carbon uptake (C source) and growth (C sink) typically decrease. This correlation raises two important questions: (i) to what degree is tree growth limited by C availability; and (ii) is growth limited by concurrent C storage (e.g., as nonstructural carbohydrates, NSC)? To test the relationships between drought, growth and C reserves, we monitored the changes in NSC levels and constructed stem growth chronologies of mature Pinus halepensis Miller trees of three drought stress levels growing in Yatir forest, Israel, at the dry distribution limit of forests. Moderately stressed and stressed trees showed 34 and 14% of the stem growth, 71 and 31% of the sap flux density, and 79 and 66% of the final needle length of healthy trees in 2012. In spite of these large reductions in growth and sap flow, both starch and soluble sugar concentrations in the branches of these trees were similar in all trees throughout the dry season (2-4% dry mass). At the same time, the root starch concentrations of moderately stressed and stressed trees were 47 and 58% of those of healthy trees, but never <2% dry mass. Our results show that all the studied trees maintain a fairly good coordination between C supply and demand, and even during prolonged drought there is more than one way for a tree to maintain a positive C balance.
Language
  • English
Open access status
bronze
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Persistent URL
https://folia.unifr.ch/global/documents/124389
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