A COMPARATIVE-STUDY OF THE GROWTH AND MORPHOLOGY OF 8 GRASS SPECIES FROM HABITATS WITH DIFFERENT NUTRIENT AVAILABILITIES

1. To find out which properties enable plant species to dominate in nu trient-poor habitats and which properties benefit species in nutrient- rich habitats, we studied the growth and morphology of eight perennial grass species from habitats with contrasting soil fertilities in a po t experiment under controlled conditions in a glasshouse. 2. The speci es were grown under nutrient-poor and nutrient-rich conditions. Ranked from the least responsive to the most responsive to the supply of nut rients they were: Festuca ovina, F. rubra, Anthoxanthum odoratum, F. a rundinacea, Alopecurus pratensis, F. pratensis, Arrhenatherum elatius, Lolium perenne. 3. The response correlated positively with the Ellenb erg nitrogen number of the species. No differences in initial relative growth rate were found between the species, but after 4 weeks the pla nt dry weight increased with increasing nitrogen number as a result of variation in embryo plus endosperm weight. 4. Species characteristic of nutrient-rich hayfields are taller and show a more homogeneous vert ical distribution of photosynthetic area than the species from nutrien t-poor habitats, which have most of their leaf area below 15 cm. Speci es from the nutrient-poor habitats allocated less dry matter to the ro ots and consequently more to the shoot, than species from nutrient-ric h conditions. However, leaf and root morphology seem to be most clearl y adapted to the habitat. 5. Species from nutrient-rich habitats have a higher specific leaf area (SLA) than species from nutrient-poor habi tats, while species from nutrient-poor habitats had more root length p er unit root weight (SRL) than species from nutrient-rich habitats.