http://www.cnr.it/ontology/cnr/individuo/prodotto/ID294034
Multilayer canopy systems: plant energy dissipation and photoprotection mechanisms along the vertical profile - Fagus sylvatica L. as a model (Abstract/Poster in atti di convegno)
- Type
- Label
- Multilayer canopy systems: plant energy dissipation and photoprotection mechanisms along the vertical profile - Fagus sylvatica L. as a model (Abstract/Poster in atti di convegno) (literal)
- Anno
- 2014-01-01T00:00:00+01:00 (literal)
- Alternative label
Scartazza Andrea (1), Di Baccio Daniela (1), Bertolotto Pierangelo (1), Gavrichkova Olga (1), Matteucci Giorgio (1,2) (2014)
Multilayer canopy systems: plant energy dissipation and photoprotection mechanisms along the vertical profile - Fagus sylvatica L. as a model
in AGROCOP Conference, Porano (Italy), 16-17 October
(literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
- Scartazza Andrea (1), Di Baccio Daniela (1), Bertolotto Pierangelo (1), Gavrichkova Olga (1), Matteucci Giorgio (1,2) (literal)
- Note
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
- 1 Institute of Agro-environment and Forest Biology (IBAF), CNR - Italy
2 Institute for Agricultural and Forestry Systems in the Mediterranean (ISAFoM), CNR - Italy (literal)
- Titolo
- Multilayer canopy systems: plant energy dissipation and photoprotection mechanisms along the vertical profile - Fagus sylvatica L. as a model (literal)
- Abstract
- Acclimation of leaf photosynthesis to different light environments is a fundamental factor that
influences photosynthetic capacity and, consequently, productivity. Light interception and nitrogen
content (N) are main factors driving carbon (C) assimilation at the leaf scale, and many hypotheses
and models on the acclimation of leaf photosynthetic capacity have been formulated. Most of these
studies focus on shade and sun leaves, but do not take into account the vertical irradiance gradient
as a continuum under which plasticity of leaf structure and photosynthetic capacity can be
expressed. On the other hand, the metabolic functionality of leaves along the vertical profile of treelike
plants may reflect the different environmental conditions under which other plant species grow
and develop in the multilayer canopy of agroforestry systems. Indeed, under optimal nutrient and
water supply, in mixed-cropping systems or in Multiple Cropping Systems (MCS) the main
competition factor becomes the light exposure and interception by leaves. In this perspective, the
study of leaf response to the variable light conditions of the different layers along the vertical
profile of a deep canopy, such as that of a beech forest, can represent a valuable model. In Southern
Europe the beech forest canopy shows high plasticity to cope with heat and drought, due to a high
adaptability of the leaf photosynthetic capacity to micro-climate changes over days or weeks and to
climate fluctuations during the season. It is conceivable that the beech leaves have developed highly
specialized mechanisms to regulate the photosynthetic capacity and the light use efficiency at the
canopy level under different environmental conditions. We studied the different structure and
metabolic functionality of leaves along the vertical profile of a beech canopy, in order to clarify the
morpho-physiological and molecular mechanisms underlying the adaptability of the different
canopy layers to variable light regimes. With this aim, determinations of leaf structure (leaf mass
per unit area - LMA, thickness and density), N distribution, gas exchange and chlorophyll
fluorescence, photosynthetic pigments and antioxidant status were performed along three canopy
layers of a beech (Fagus sylvatica L.) forest near Collelongo (Abruzzo region, Central Italy), where
a permanent experimental facility (Selva Piana) was installed since 1991. Results revealed a
progressive increase of the maximal carboxylation rate (Vcmax), light driven electron transport rate
(Jmax) and CO2 assimilation rate from the bottom to the upper canopy layers, associated to a gradient
in LMA and N content per unit of leaf area. The light response curves of the actual efficiency of
PSII photochemistry (?PSII) and non-photochemical quenching (NPQ), suggested a different
strategy in the radiative and non-radiative energy dissipation capacity depending on the canopy
layer position along the vertical profile. This leaf differential response corresponded to qualiquantitative
variations in photosynthetic pigment composition. In particular, the highest light
exposure determined an enhancement of the Chl a/Chl b ratio and ?-carotene content. The
xanthophyll (V+A+Z) pool, closely related to the leaf energy dissipation and photo-protective
capacity, progressively increased with the increasing height of the canopy layer (bottom,
intermediate, upper). Modifications of the leaf antioxidative system gave insights on the nature and
action of defence/adaptation plant mechanisms to the multilayer canopy environments. Applications
for managing of MCS are discussed. (literal)
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