IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
No time for candy: passionfruit (Passiflora edulis) plants down-regulate damage-induced extra floral nectar production in response to light signals of competition
Autor/es:
IZAGUIRRE, M. M.; MAZZA, C. A.; ASTIGUETA, S.; CIARLA, A.; BALLARÉ, C. L.
Revista:
OECOLOGIA
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2013 vol. 173 p. 213 - 221
ISSN:
0029-8549
Resumen:
Plant fitness is often defined by the combined effects of herbivory and
competition, and plants must strike a delicate balance between their
ability to capture limiting resources and defend against herbivore
attack. Many plants use indirect defenses, such as volatile compounds
and extrafloral nectaries (EFN), to attract canopy arthropods that are
natural enemies of herbivorous organisms. While recent evidence suggests
that upon perception of low red to far-red (R:FR) ratios, which signal
the proximity of competitors, plants down-regulate resource allocation
to direct chemical defenses, it is unknown if a similar
phytochrome-mediated response occurs for indirect defenses. We evaluated
the interactive effects of R:FR ratio and simulated herbivory on nectar
production by EFNs of passionfruit (Passiflora edulis f. flavicarpa).
The activity of petiolar EFNs dramatically increased in response to
simulated herbivory and hormonal treatment with methyl jasmonate (MeJA).
Low R:FR ratios, which induced a classic ?shade-avoidance? repertoire
of increased stem elongation in P. edulis,
strongly suppressed the EFN response triggered by simulated herbivory or
MeJA application. Strikingly, the EFN response to wounding and light
quality was localized to the branches that received the treatments. In
vines like P. edulis, a local response
would allow the plants to precisely adjust their light harvesting and
defense phenotypes to the local conditions encountered by individual
branches when foraging for resources in patchy canopies. Consistent with
the emerging paradigm that phytochrome regulation of jasmonate
signaling is a central modulator of adaptive phenotypic plasticity, our
results demonstrate that light quality is a strong regulator of indirect
defenses.