Leaf and whole-plant water relations of the Patagonian conifer Austrocedrus chilensis: implications on its drought resistance capacity

GYENGE, J.; MARIA ELENA FERNANDEZ; DALLA SALDA, G.; SCHLICHTER, T.

Annals of Forest Science

Año: 2005 vol. 62 p. 297 - 302

Physiological studies have suggested that A. chilensis would survive during drought avoiding water stress through an early stomatal closure. However, there are no studies that have explored other potential mechanisms related to drought resistance or avoidance. The objectives were: (1) to measure hydraulic resistance, vulnerability to cavitation and leaf water relations, and (2) to compare these characteristics between different provenances. Pressure-volume curves demonstrate that A. chilensis has high osmotic potentials at full turgor, high water potentials at turgor loss point, low modulus of elasticity, and did not present elastic or osmotic adjustments after drought. Compared to other gymnosperms, A. chilensis has a high total plant resistance but also a high vulnerability to cavitation. We found no differences between the studied provenances in these variables. Our results confirm that A. chilensis is a drought-avoidance species, and suggest that phenotypic morphological differentiation between populations allows the species to survive throughout its broad distribution.