Seasonal variability in flower lifespan in common chicory (Cichorium intybus L.)

Abstract

Flower opening and closure is a crucial process in pollinator attraction. The duration of flower lifespan, the time between flower opening and closure, represents a trade-off between pollinator attraction and the cost of flower maintenance caused by increased respiration and transpiration rates, particularly when ambient temperature is high. Moreover, flower lifespan can decrease rates of autonomous self-pollination. We examined whether flower lifespan in common chicory (Cichorium intybus) is determined by pollinator availability and/or by abiotic factors such as temperature and day length. Plants were investigated in one study site in East Slovakia during the summer and autumn seasons of 2016 and 2019, respectively. Individual flower opening and closure and pollinator availability were recorded during the flowering season and across various hand-pollination treatments including self-pollination, cross-pollination, no pollination and an unmanipulated control. Flower lifespan was positively correlated to time of the season as well as to lower pollinator abundance. Unpollinated flowers remained open for a longer period than self-pollinated, cross-pollinated and control flowers. The time of the season has stronger impact on flower lifespan than the onset of pollination. Findings in this study indicate that seasonal changes characterized by daytime temperature, day length and pollinator availability need to be taken into account in research of flowering time.