Experimental evidence for benefit of self discrimination in roots of a clonal plant

Abstract

Some plants express self discrimination in their roots, which allows them to preferentially reduce antagonistic interactions and increase facilitative interactions with genetically identical ramets or individuals. However, our understanding of how self discrimination contributes to reproduction in plants is limited. Here, we report that self discrimination is adaptive in the clonal plant Kalanchoë daigremontiana. Plants were grown with a self or nonself plant for 30 days. Furthermore, root allocation patterns associated with self and non-self plants and their root exudates were investigated in a split-root experiment. Biomass of shoot, root, and plantlets and number of plantlets per plant were examined. Plants expressed root behaviour that is specific to the non-self condition: plants developed more roots when growing with a non-self plant than when growing with a self plant. Similar root behaviour was observed in the root exudate experiment, in which it reduced both root growth and clonal reproduction in non-self competitor plants. As a result, plants competing with a clonal self plant produced more clonal plantlets than plants competing with a non-self plant. These experimental results provide evidence that self discrimination through root exudation is adaptive for K. daigremontiana plants.