IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Phosphorus reserves increase grass regrowth after defoliation
Autor/es:
OYARZÁBAL, M.; OESTERHELD, M.
Revista:
OECOLOGIA
Editorial:
SPRINGER
Referencias:
Año: 2009 vol. 159 p. 717 - 724
ISSN:
0029-8549
Resumen:
Accumulation of P above levels that promote
growth, a common plant response called luxury consumption,
can be considered as a form of reserve to support
future growth when the nutrient can subsequently be mobilized.
However, the eVect of P reserves on regrowth following
defoliation has not been demonstrated. We tested the
hypothesis that P luxury consumption increases plant tolerance
to defoliation. We performed two experiments with
four grass species from a continuously grazed temperate
grassland in the Flooding Pampa (Argentina). The Wrst
experiment, aimed at generating P luxury consumption by
fertilization, resulted in one species (Sporobolus indicus)
showing luxury consumption. In this way, we were able to
obtain plants of S. indicus with similar biomass but contrasting
amounts of P reserves. The second experiment
evaluated the subsequent regrowth following defoliation on
a P-free medium of these plants diVering in P reserves.
Regrowth was larger for plants that had shown P luxury
consumption during a previous period than for plants with
lower levels of P reserves. During regrowth these plants
showed a clear pattern of P remobilization from the stubble,
crown, and root compartments to the regrowing tissue, in
addition to a likely reutilization of P present in leaf-growth
zones. This work is the Wrst showing that high levels of P
reserves can confer tolerance to defoliation by promoting
compensatory growth under P deWciency.Vect of P reserves on regrowth following
defoliation has not been demonstrated. We tested the
hypothesis that P luxury consumption increases plant tolerance
to defoliation. We performed two experiments with
four grass species from a continuously grazed temperate
grassland in the Flooding Pampa (Argentina). The Wrst
experiment, aimed at generating P luxury consumption by
fertilization, resulted in one species (Sporobolus indicus)
showing luxury consumption. In this way, we were able to
obtain plants of S. indicus with similar biomass but contrasting
amounts of P reserves. The second experiment
evaluated the subsequent regrowth following defoliation on
a P-free medium of these plants diVering in P reserves.
Regrowth was larger for plants that had shown P luxury
consumption during a previous period than for plants with
lower levels of P reserves. During regrowth these plants
showed a clear pattern of P remobilization from the stubble,
crown, and root compartments to the regrowing tissue, in
addition to a likely reutilization of P present in leaf-growth
zones. This work is the Wrst showing that high levels of P
reserves can confer tolerance to defoliation by promoting
compensatory growth under P deWciency.Wrst
experiment, aimed at generating P luxury consumption by
fertilization, resulted in one species (Sporobolus indicus)
showing luxury consumption. In this way, we were able to
obtain plants of S. indicus with similar biomass but contrasting
amounts of P reserves. The second experiment
evaluated the subsequent regrowth following defoliation on
a P-free medium of these plants diVering in P reserves.
Regrowth was larger for plants that had shown P luxury
consumption during a previous period than for plants with
lower levels of P reserves. During regrowth these plants
showed a clear pattern of P remobilization from the stubble,
crown, and root compartments to the regrowing tissue, in
addition to a likely reutilization of P present in leaf-growth
zones. This work is the Wrst showing that high levels of P
reserves can confer tolerance to defoliation by promoting
compensatory growth under P deWciency.Sporobolus indicus)
showing luxury consumption. In this way, we were able to
obtain plants of S. indicus with similar biomass but contrasting
amounts of P reserves. The second experiment
evaluated the subsequent regrowth following defoliation on
a P-free medium of these plants diVering in P reserves.
Regrowth was larger for plants that had shown P luxury
consumption during a previous period than for plants with
lower levels of P reserves. During regrowth these plants
showed a clear pattern of P remobilization from the stubble,
crown, and root compartments to the regrowing tissue, in
addition to a likely reutilization of P present in leaf-growth
zones. This work is the Wrst showing that high levels of P
reserves can confer tolerance to defoliation by promoting
compensatory growth under P deWciency.S. indicus with similar biomass but contrasting
amounts of P reserves. The second experiment
evaluated the subsequent regrowth following defoliation on
a P-free medium of these plants diVering in P reserves.
Regrowth was larger for plants that had shown P luxury
consumption during a previous period than for plants with
lower levels of P reserves. During regrowth these plants
showed a clear pattern of P remobilization from the stubble,
crown, and root compartments to the regrowing tissue, in
addition to a likely reutilization of P present in leaf-growth
zones. This work is the Wrst showing that high levels of P
reserves can confer tolerance to defoliation by promoting
compensatory growth under P deWciency.Vering in P reserves.
Regrowth was larger for plants that had shown P luxury
consumption during a previous period than for plants with
lower levels of P reserves. During regrowth these plants
showed a clear pattern of P remobilization from the stubble,
crown, and root compartments to the regrowing tissue, in
addition to a likely reutilization of P present in leaf-growth
zones. This work is the Wrst showing that high levels of P
reserves can confer tolerance to defoliation by promoting
compensatory growth under P deWciency.Wrst showing that high levels of P
reserves can confer tolerance to defoliation by promoting
compensatory growth under P deWciency.Wciency.