Differential utilization of a shallow - water pulse by six shrub species in the Patagonian steppe
A field experiment was performed to improve understanding of the functional diversity of western Patagonian shrubs. Anarthrophyllum rigidum, Adesmia volckmanni, Berberis heterophylla, Mulinum spinosum, Schinus poligamus and Senecio filaginoides were compared in their capacity to absorb water from a 10-mm pulse enriched in deuterium and applied at the beginning of the dry summer. Xylem-water enrichment 14 days after watering was rather subtle, but the upper-soil signal was clear enough to distinguish shallow from deeper absorption. According to a linear mixing model, the proportion of surface-pulse water relative to total water uptake was maximum for Senecio [29-38 percent] and Mulinum [22-32 percent], both relatively shallow-rooted species, intermediate for Berberis [16-17 percent] and Schinus [6-9 percent], and negligible for the two N-fixing Fabaceae: Adesmia [less than 1 percent] and Anarthrophyllum [ less than 3 percent], despite this last one having a dimorphic [tap. +. shallow] root system. It is hypothesized that shallow-water pulses may be more profitable in terms of nitrogen than of water, and thus constitute a higher-quality resource for those species only able to use N from soil sources.
| Main Authors: | , |
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| Format: | Texto biblioteca |
| Language: | eng |
| Subjects: | MIXING MODELS, NITROGEN FIXATION, PLANT WATER UPTAKE, PULSED RESOURCES, ROOT DISTRIBUTION, STABLE ISOTOPES, AGRICULTURAL ECONOMICS, DEUTERIUM, FUNCTIONAL CHANGE, LEGUME, PLANT WATER RELATIONS, ROOT SYSTEM, SHALLOW WATER, SHRUB, SOIL NITROGEN, STABLE ISOTOPE, STEPPE, PATAGONIA, ADESMIA, ADESMIA VOLCKMANNII, ANARTHROPHYLLUM, BERBERIS, BERBERIS HETEROPHYLLA, FABACEAE, MULINUM, MULINUM SPINOSUM, SCHINUS, SENECIO, SENECIO FILAGINOIDES, |
| Online Access: | http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=46641 |
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