INVESTIGADORES
GHERMANDI Luciana
artículos
Título:
Defoliation frequency affects morphophysiological traits in the bunchgrass Poa
Autor/es:
GITTINS, C.; BUSSO, C., G. BECKER; L. GHERMANDI & SIFFREDI,G.L.
Revista:
PHYTON - INTERNATIONAL JOURNAL OF EXPERIMENTAL BOTANY BA ARGENTINA
Editorial:
FUNDACION ROMULO RAGGIO
Referencias:
Año: 2010 p. 55 - 69
ISSN:
0031-9457
Resumen:
Abstract. Poa ligularis is an important forage in Patagonian
rangelands. Populations of this perennial bunchgrass have been severely
affected by overgrazing. We propose that increased defoliation
frequencies will decrease (1) aerial- and belowground dry matter
production, (2) root survival, and (3) concentration and content of
total non-structural crown + root carbohydrates, and (4) increase root
mortality. Five defoliation frequencies (plus 1 control) were applied
in a representative grassland of the Occidental District in Patagonia
during two consecutive growing seasons. All four hypotheses were
rejected. Aerial and belowground dry matter production increased
from one to two or three defoliations. Root production and dynamics
were not affected by the study defoliation frequencies. Total nonstructural
carbohydrate (TNC) concentration (%) and content (g/
plant) in crown + roots were increased when defoliations augmented
from three to five times (%, 2002-2003), or from two to three
times (% and g/plant, 2003-04) during the growing cycle, but TNC
contents in 2002-03. These results suggest that TNC availability in
crown and roots, and plant vigor on P. ligularis in dry Patagonia are
favored by light to moderate defoliation frequencies (no more than
two or three defoliations annually) immediately before internode
elongation to 5 cm stubble height each.
favored by light to moderate defoliation frequencies (no more than
two or three defoliations annually) immediately before internode
elongation to 5 cm stubble height each.
rangelands. Populations of this perennial bunchgrass have been severely
affected by overgrazing. We propose that increased defoliation
frequencies will decrease (1) aerial- and belowground dry matter
production, (2) root survival, and (3) concentration and content of
total non-structural crown + root carbohydrates, and (4) increase root
mortality. Five defoliation frequencies (plus 1 control) were applied
in a representative grassland of the Occidental District in Patagonia
during two consecutive growing seasons. All four hypotheses were
rejected. Aerial and belowground dry matter production increased
from one to two or three defoliations. Root production and dynamics
were not affected by the study defoliation frequencies. Total nonstructural
carbohydrate (TNC) concentration (%) and content (g/
plant) in crown + roots were increased when defoliations augmented
from three to five times (%, 2002-2003), or from two to three
times (% and g/plant, 2003-04) during the growing cycle, but TNC
contents in 2002-03. These results suggest that TNC availability in
crown and roots, and plant vigor on P. ligularis in dry Patagonia are
favored by light to moderate defoliation frequencies (no more than
two or three defoliations annually) immediately before internode
elongation to 5 cm stubble height each.
favored by light to moderate defoliation frequencies (no more than
two or three defoliations annually) immediately before internode
elongation to 5 cm stubble height each.
Poa ligularis is an important forage in Patagonian
rangelands. Populations of this perennial bunchgrass have been severely
affected by overgrazing. We propose that increased defoliation
frequencies will decrease (1) aerial- and belowground dry matter
production, (2) root survival, and (3) concentration and content of
total non-structural crown + root carbohydrates, and (4) increase root
mortality. Five defoliation frequencies (plus 1 control) were applied
in a representative grassland of the Occidental District in Patagonia
during two consecutive growing seasons. All four hypotheses were
rejected. Aerial and belowground dry matter production increased
from one to two or three defoliations. Root production and dynamics
were not affected by the study defoliation frequencies. Total nonstructural
carbohydrate (TNC) concentration (%) and content (g/
plant) in crown + roots were increased when defoliations augmented
from three to five times (%, 2002-2003), or from two to three
times (% and g/plant, 2003-04) during the growing cycle, but TNC
contents in 2002-03. These results suggest that TNC availability in
crown and roots, and plant vigor on P. ligularis in dry Patagonia are
favored by light to moderate defoliation frequencies (no more than
two or three defoliations annually) immediately before internode
elongation to 5 cm stubble height each.
favored by light to moderate defoliation frequencies (no more than
two or three defoliations annually) immediately before internode
elongation to 5 cm stubble height each.
P. ligularis in dry Patagonia are
favored by light to moderate defoliation frequencies (no more than
two or three defoliations annually) immediately before internode
elongation to 5 cm stubble height each.