High-light stress does not impair biomass accumulation of sun-acclimated tropical tree seedlings (Calophyllum longifolium Willd. and Tectona grandis L. f.).
Plant Biol (Stuttg)
; 8(1): 31-41, 2006 Jan.
Article
em En
| MEDLINE
| ID: mdl-16435267
Studies with seedlings of tropical rainforest trees ( Calophyllum longifolium Willd.; Tectona grandis L. f.) were designed to test whether high-light stress affects photosynthetic performance and growth. Seedlings were cultivated in pots at a field site in Central Panama (9 degrees N) and separated into two groups: (1) plants exposed to full solar radiation; (2) plants subjected to automatic neutral shading (48 %) whenever visible irradiance surpassed 1000, 1200, or 1600 micromol photons m-2 s-1. After 2-4 months, chlorophyll fluorescence (Fv/Fm ratio), photosynthetic net CO2 uptake, pigment composition, alpha-tocopherol content of leaves, and plant biomass accumulation were measured. Fully sun-exposed, compared to periodically shaded plants, experienced substantial high-light stress around midday, indicated by photoinhibition of photosystem II and depressed net CO2 uptake. Higher contents of xanthophyll cycle pigments, lutein, and alpha-tocopherol showed an enhancement of photoprotection in fully sun-exposed plants. However, in all experiments, the maximum capacity of net CO2 uptake and plant dry mass did not differ significantly between the two treatments. Thus, in these experiments, high-light stress did not impair productivity of the seedlings studied. Obviously, the continuously sun-exposed plants were capable of fully compensating for any potential costs associated with photoinhibition and repair of photosystem II, reduced CO2 assimilation, and processes of high-light acclimation.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Luz Solar
/
Árvores
/
Calophyllum
/
Verbenaceae
/
Plântula
Idioma:
En
Revista:
Plant Biol (Stuttg)
Assunto da revista:
BOTANICA
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Panamá
País de publicação:
Reino Unido