Relationship between the Al resistance of grasses and their adaptation to an infertile habitat
Résumé
Background and Aims Original data on Al resistance, relative growth rate and leaf traits of five European grasses as well as literature data on Al resistance, habitat preference and traits of grasses were considered to determine whether (a) Al resistance is correlated to a growth conservative strategy and (b) species occurrence could be useful to assess Al toxicity in meadows on acid soils. Methods The Al resistance of 15 species was represented by the Al activity in nutrient solution that resulted in a 50 % decrease in root length, {Al3+}(50), or, for published values, in root or plant biomass. The correlations between Al resistance and acidity or nitrogen indices and the correlation between Al resistance and selected traits (relative growth rate, leaf dry matter content, specific leaf area and leaf thickness) were calculated. Principal component analysis was used for the characterization of the relationships between Al resistance and measured traits. Key Results The {Al3+}(50) values of the resistant species Molinia caerulea and Sieglingia decumbens were 13 and 26 mu m {Al3+}(50), respectively. The known Al resistance of 15 species that were mainly of the intermediate strategy competitor-stress tolerator-ruderal (C-S-R) type and of the S type was correlated with Ellenberg's nitrogen and acidity indices. For the whole set of species, the correlation between Al resistance and traits was not significant. Conclusion The Al resistance of the C-S-R species was variable and independent of their traits. S-type species, adapted to acid soils and with traits of conservative strategy, displayed Al resistance. The large difference in Al resistance between grasses may help assess Al soil toxicity by using the abundance of grasses.
Mots clés
Al resistance
acid soils
plant functional traits
grassland
Arrhenatherum elatius
grasses
Festuca rubra
Helictotrichon sulcatum
Molinia
caerulea
Sieglingia decumbens
Relative growth-rate
organic-acid exudation
dry-matter content
leaf-area
aluminum tolerance
interspecific variation
chemical-composition
soil acidity
high-level
plants