Background
The authors write that "alternatively to shifts in abundance and distribution, plants may persist in a changing climate through evolutionary adaptation and phenotypic plasticity," citing Jump and Penuelas (2005), Gienapp et al. (2008), Nicotra et al. (2010) and Hoffmann and Sgro (2011).

What was done
In a study designed to further investigate these two phenomena, Frei et al. grew low (1200 m a.s.l.) and high (1800 m a.s.l.) altitude plants of three montane grassland species (Trifolium montanum L., Ranunculus bulbosus L. and Briza media L.) in controlled-climate chambers maintained at the elevated temperatures predicted for future conditions and in control treatments corresponding to current ambient conditions, while all other environmental parameters were kept identical.

What was learned
The three Swiss scientists report that "the three species exhibited trait plasticity with respect to temperature," and they say in particular that their observed "plasticity in growth and flowering phenology determines the ability of the study species to respond to elevated temperature by buffering against detrimental effects of rapid climate change and allowing time for evolutionary adaptation."

What it means
In their final word on the subject, Frei et al. state that the plants' "selection on several traits suggests that the three species have the potential for evolutionary changes, which might allow them to adapt to a future climate."

References
Gienapp, P., Teplitsky, C., Alho, J.S., Mills, J.A. and Merila, J. 2008. Climate change and evolution: disentangling environmental and genetic responses. Molecular Ecology 17: 167-178.

Hoffmann, A.A. and Sgro, C.M. 2011. Climate change and evolutionary adaptation. Nature 470: 479-485.

Jump, A.S. and Penuelas, J. 2005. Running to stand still: adaptation and the response of plants to rapid climate change. Ecology Letters 8: 1010-1020.

Nicotra, A.B., Atkin, O.K., Bonser, S.P., Davidson, A.M., Finnegan, E.J., Mathesius, U., Poot, P., Purugganan, M.D., Richards, C.L., Valladares, F. and van Kleunen, M. 2010. Plant phenotypic plasticity in a changing climate. Trends in Plant Science 15: 684-692.