Journal Article

Nitrogen and potassium effects on xylem cavitation and water-use efficiency in poplars

H. P. Harvey and R. van den Driessche

in Tree Physiology

Volume 19, issue 14, pages 943-950
Published in print December 1999 | ISSN: 0829-318X
Published online December 1999 | e-ISSN: 1758-4469 | DOI: http://dx.doi.org/10.1093/treephys/19.14.943
Nitrogen and potassium effects on xylem cavitation and water-use efficiency in poplars

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Effects of N and K nutrition on drought and cavitation resistance were examined in six greenhouse-grown poplar clones: Populus trichocarpa (Torr. & Gray) and its hybrids with P. deltoides Bartr. and P. euramericana (Dole) Guinier, before and after preconditioning to water stress. Both tendency to cavitate and water-use efficiency (WUE) increased when N supply was increased, whereas K supply had little impact on cavitation. Mean xylem vessel diameters increased from 36.6 μm at low-N supply to 45.2 μm at high-N supply. Drought-hardy clones, which were relatively resistant to cavitation, had the smallest mean vessel diameters. Vulnerability to cavitation had a weakly positive relationship with vessel diameter, and a negative correlation with transpiration. Drought hardening offered no protection against cavitation in a subsequent drought. Under drought conditions, increasing N supply increased leaf loss and decreased water potentials, whereas increasing K supply decreased leaf loss. Drought-resistant clones exhibited similar WUE to drought-susceptible clones, but had smaller, more numerous stomata and greater leaf retention under drought conditions.

Keywords: cottonwood; embolism; Populus deltoides; P. euramericana; P. trichocarpa

Journal Article.  0 words. 

Subjects: Plant Sciences and Forestry

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