Abstrakt
One of the strategies employed by plants to counter weed control is to survive and resprout from belowground organs (the tolerance strategy). This strategy is possible because of the existence of specialized organs like rhizomes, roots with adventitious buds, or tubers.
These organs have multiple functions: clonal growth, resprouting, and vegetative propagation. Such functions are facilitated by the ability to store carbohydrates and reserve meristems in order to produce new aboveground shoots and new fine roots after seasonal dormancy or disturbance.
Weeds usually combine the tolerance strategy with other strategies, namely with avoidance and resistance strategies, typical for short-lived weeds dependent on seed reproduction. Which strategy becomes the most important depends on weed control practices, plant traits, and environmental conditions.
Weeding practices can be characterized as a type of disturbance regime with specific timing, predictability, severity, and frequency. Plant traits contributing to tolerance strategies also include the quantity of stored carbohydrates and size of the budbank.
Regeneration after weeding, however, may also be affected by other factors like plant ontogeny or soil nitrogen availability. Weeding represents a strong selective pressure leading to selection of the best adapted genotypes.
While low intensity mechanical weeding selects for tolerance strategies, i.e., weeds resprouting from specialized organs, high intensity mechanical weeding selects for avoidance strategies, i.e. weeds regenerating from seeds. Finally, the use of herbicides favors short-lived weeds producing easily dispersed seeds that allow for the spread of resistant genotypes.