TY - JOUR A1 - Petru, Martina A1 - Tielbörger, Katja A1 - Belkin, Ruthie A1 - Sternberg, Marcelo A1 - Jeltsch, Florian T1 - Life history variation in an annual plant under two opposing environmental constraints along an aridity gradient N2 - Environmental gradients represent an ideal framework for studying adaptive variation in the life history of plant species. However, on very steep gradients, largely contrasting conditions at the two gradient ends often limit the distribution of the same species across the whole range of environmental conditions. Here, we study phenotypic variation in a winter annual crucifer Biscutella didyma persisting along a steep gradient of increasing rainfall in Israel. In particular, we explored whether the life history at the arid end of the gradient indicates adaptations to drought and unpredictable conditions, while adaptations to the highly competitive environment prevail at the mesic Mediterranean end. We examined several morphological and reproductive traits in four natural populations and in populations cultivated in standard common environment. Plants from arid environments were faster in phenological development, more branched in architecture and tended to maximize reproduction, while the Mediterranean plants invested mainly in vertical vegetative growth. Differences between cultivation and field in diaspore production were very large for arid populations as opposed to Mediterranean ones, indicating a larger potential to increase reproduction under favorable conditions. Our overall findings indicate two strongly opposing selective forces at the two extremes of the aridity gradient, which result in contrasting strategies within the studied annual plant species Y1 - 2006 UR - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/31419 UR - http://www3.interscience.wiley.com/journal/117966123/home ER -