Nutrient contents and eYciencies of beech and spruce saplings as inXuenced by competition and O3/CO2 regime.
Nenhuma Miniatura disponível
Data
2009
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
Saplings of Fagus sylvatica and Picea abies
were grown under conditions of intra and interspeciWc competition
in a 2-year phytotron study under combinations of
ambient and elevated ozone (+O3 which is 2 £ O3, but
<150 nl l¡1) as well as carbon dioxide concentrations
(+CO2 which is amb. CO2 + 300 l CO2 l¡1) in a full factorial
design. Saplings were analysed for various mineral
nutrients in diVerent plant organs as well as biomass production
and crown development. The study was based on
the assumption that nutritional parameters important for
growth and competitiveness are aVected by stress defence
under limiting nutrient supply. The hypotheses tested were
(1) that nutrient uptake-related parameters (a) as well as
eYciencies in nutrient use for above-ground competition
(b) of beech rather than spruce are impaired by the exposure
to elevated O3 concentrations, (2) that the eYciency in
nutrient uptake of spruce is enhanced by elevated CO2
concentrations in mixed culture, and (3) that the ability to
occupy above-ground space at low nutrient cost is co-determinant
for the competitive success in mixed culture. Clear
nitrogen deWciencies were indicated for both species during
the 2-year phytotron study, although foliar nitrogen-biomass
relationships were not so close for spruce than for beech.
O3 stress did not impair nutrient uptake-related parameters
of beech; thus hypothesis (1a). was not supported. A negative
eVect of elevated O3 (under amb. CO2) on the N and P based
eYciencies in above-ground space occupation (i.e. lower
crown volume per unit of N or P invested in stems, limbs
and foliage) of beech supported hypothesis (1b). It appeared
that ozone stress triggered a nutrient demand for stress
defence and tolerance at the expense of above-ground competition
(trade-oV). Crown volume of beech under O3 stress
was stabilized in monoculture by increased nutrient uptake.
In general, the +CO2-treatment was able to counteract the
impacts of 2 £ O3. Elevated CO2 caused lower N and S
concentrations in current-year foliage of both tree species,
slightly higher macronutrient amounts in the root biomass
of spruce, but did not increase the eYciencies in nutrient
uptake of spruce in mixed culture. Therefore hypothesis (2)
was not supported. At the end of the experiment spruce
turned out to be the stronger competitor in mixed culture as
displayed by its higher total shoot biomass and crown volume.
The amounts of macronutrients in the above-ground biomass
of spruce individuals in mixed culture distinctly exceeded
those of beech, which had been strongly reduced by interspeciWc
competition. The superior competitiveness of spruce
was related to higher N and P-based eYciencies in aboveground
space occupation as suggested in hypothesis (3).
Descrição
Palavras-chave
Competition, Nutritional status, Nutrient contents, Nutrient effciencies
Citação
RODENKIRCHEN, H. et al. Nutrient contents and effciencies of beech and spruce saplings as influenced by competition and O3/CO2 regime. European Journal of Forest Research, v. 128, p. 117-128, 2009. Disponível em: <https://link.springer.com/article/10.1007%2Fs10342-008-0221-y>. Acesso em: 20 de jul. 2017.