Plant origin and trade-off between generative and vegetative reproduction determine germination behaviour of a dominant grass species along climatic gradients
Abstrakt
An increasing number of studies explore the effects of climate change on plants; less studies have paid attention to germination. Even less is known on a trade-off between investment to generative and vegetative reproduction.
To assess how conditions of plant origin, germination climate and seed mass affect species' germination, we studied Festuca rubra originating from localities situated along a natural climatic grid with a factorial combi-nation of temperatures and precipitations. Germination of seeds of different origin was tested in two temperature and two soil moisture regimes, simulating extremes of the climatic grid.
To study the relationship between generative and vegetative reproduction, we used previous data on vegetative traits of the species originating from the same study system. Higher seed mass and warm germination temperature contributed to higher and faster germination.
However, the effects of temperature and moisture interacted leading to low germination and high proportion of dormant seeds in warm, dry conditions. Seeds of plants originating from warm climate had higher germination than those from cold climate; the effects of original climate were partly due to differences in seed mass.
Total germination negatively correlated with plant performance variables contributing to vegetative reproduction. Both conditions of plant origin and of germination determine species' germination and the effect of plant origin can partly be explained by seed mass.
We confirmed a trade-off between generative and vegetative reproduction indicating that, depending on the actual conditions, the species is able to modify investments to generative or vegetative reproduction.