PS 32-22
Does potential bud bank increase tolerance of short-lived plants to apical meristem demage?
Short-lived monocarpic plants that lose apical meristems are able, to varying degrees, to compensate or even overcompensate for biomass loss. Compensation has been shown to decrease with increasing plant injury, as limitation by axillary meristem availability becomes more important. However, compensatory growth can occur not just by axillary branching, but also by the activation of adventitious meristems, which largely serve as a potential bud bank. Soil nutrients, dormant axillary meristem availability, and competition can influence plant tolerance to damage. However, the role of potential bud banks (adventitious meristems initiated only after injury) is not known.
We studied 22 species of annual or biennial monocarpic herbs that have been reported as being capable of adventitious sprouting from the hypocotyl and/or roots, belonging to a total of 389 populations in various habitats and environmental conditions in Central Europe, mainly in the Czech Republic. In each plant individual, basic growth characteristics and degree of injury were recorded. Each community was described using phytosociological relevés. Environmental characteristics of the studied populations were assessed using Ellenberg indicator values (EIVs) for light, humidity and nitrogen.
Results/Conclusions
Examining of all studied short-lived monocarpic herbs, we found that, with increasing injury severity, the number of resprouting axillary branches decreased, while the number of resprouting adventitious shoots increased. For axillary branching, of the studied environmental factors, only vegetation cover had a significant effect, and this was only for injured plants, for which it was positively correlated with the number of resprouting axillary branches. In intact plants, adventitious sprouting was supported by nutrients and moisture and suppressed by light, whereas in injured plants, light and plant cover negatively affected adventitious sprouting.
Synthesis: Our results imply that although soil nutrients and competition influence plant tolerance to damage marginally, potential bud banks enable plants to overcome meristem limitation from severe damage, and, therefore, to better tolerate it. Moreover, such tolerance should help plants with this ability cope with disturbance events (e.g., grazing, mowing) associated with severe damage. Whether these plants preferentially inhabit habitats prone to recurrent disturbance remains to be examined, as do the costs associated with potential bud banks.