Université de Fribourg

Cytotypes of Centaurea stoebe found to differ in root growth using growth pouches

Collins, Alexandra R. ; Thalmann, Daniela ; Müller-Schärer, Heinz

In: Weed Research, 2013, p. -

Centaurea stoebe is native to Europe and Western Asia and was introduced into North America in the late 19th century, where it has become highly invasive. In its native range, C. stoebe occurs in two cytotypes, namely diploids (2n = 18) and tetraploids (2n = 36), but only the tetraploid form has been identified in the invaded range. We used special growth pouches to determine whether diploid and...

Université de Fribourg

Altitudinal differences in flower traits and reproductive allocation

Fabbro, Thomas ; Körner, Christian

In: Flora - Morphology, Distribution, Functional Ecology of Plants, 2004, vol. 99(1), p. 70

We tested whether alpine plants increase their effort to attract pollinators to compensate for assumed pollinator scarcity at high altitude. A three times larger fraction of the shoot was allocated to flowers in alpine plants (30 species, 2700m asl) compared to lowland plants (20 species, 600m asl), while leaf mass fraction did not differ between the altitudes. At high elevation, a three times...