Abstract/Summary

The growth and development of Fragaria vesca, as a model plant system, was investigated to better understand the control of perenniality in plants. Experiments revealed that conditions prior to and during the resumption of vegetative growth in the spring could alter the order of emergence of runners and flowers. Under natural conditions, rapid terminal shoot apical meristem growth occurred during the spring and early summer, followed by a marked decline from June; experimental study suggested this was likely to be a response to runner development. Environment was found to regulate the fate of axillary buds: low temperature (11°C) and short days (10h) promoted branch crown development, whereas at high temperatures (>18°C) runners were initiated regardless of photoperiod. Autumn conditions induced flowering and F. vesca ecotypes varied in their timing of flower initiation (inferred from emergence); a possible relationship to latitude was confounded by response variation between years in one ecotype. There was also ecotypic variation in runnering and typically those that flowered earlier runnered less. Detailed experiments on one ecotype showed that spring flower emergence and vegetative growth had a more complex response to winter chilling than that reported for many tree species, raising the question of the suitability of F. vesca as a model perennial. Greater chill accumulation advanced runner and flower emergence during forcing; the influence of warm periods during chilling was inferred using a range of chill models. Overall, the research highlights the importance of studying plant development in the natural context. An experimental approach is proposed to allow better understanding of plant ecological development, and suggestions provided for the possible implications of predicted climate change.