AI Article Synopsis

  • The study examined leaf hydraulics, gas exchange, and carbon storage in two tree species, Pinus edulis (isohydric) and Juniperus monosperma (anisohydric), focusing on how their hydraulic function relates to carbohydrate dynamics.
  • J. monosperma exhibited lower leaf hydraulic vulnerability compared to P. edulis, maintaining leaf hydraulic conductance better throughout the growing season, especially during dry conditions.
  • The results showed that P. edulis had lower photosynthesis rates and nonstructural carbohydrate content, indicating that its isohydric strategy may lead to carbon reserve depletion during the growing season.

Article Abstract

Leaf hydraulics, gas exchange and carbon storage in Pinus edulis and Juniperus monosperma, two tree species on opposite ends of the isohydry-anisohydry spectrum, were analyzed to examine relationships between hydraulic function and carbohydrate dynamics. Leaf hydraulic vulnerability, leaf water potential (Ψl ), leaf hydraulic conductance (Kleaf ), photosynthesis (A), stomatal conductance (gs) and nonstructural carbohydrate (NSC) content were analyzed throughout the growing season. Leaf hydraulic vulnerability was significantly lower in the relatively anisohydric J. monosperma than in the more isohydric P. edulis. In P. edulis, Ψl dropped and stayed below 50% loss of leaf hydraulic conductance (P₅₀) early in the day during May, August and around midday in September, leading to sustained reductions in Kleaf . In J. monosperma, Ψl dropped below P₅₀ only during August, resulting in the maintenance of Kleaf during much of the growing season. Mean A and gs during September were significantly lower in P. edulis than in J. monosperma. Foliar total NSC was two to three times greater in J. monosperma than in P. edulis in June, August and September. Consistently lower levels of total NSC in P. edulis suggest that its isohydric strategy pushes it towards the exhaustion of carbon reserves during much of the growing season.

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http://dx.doi.org/10.1111/nph.13170DOI Listing

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