Communication between Two <i>Lactuca</i> Species

Abstract

There is increasing evidence of plant communication and behavior. We examine how two Lactuca species, L. sativa and L. serriola , communicate with themselves and one another via root exudates. We exposed both species to their own, to the same species, and to the other species root exudates. We then measured the length of their primary root as a proxy for competitive effort. L. serriola produced longer roots when exposed to its own exudates relative to when exposed to L. sativa ’ s . In contrast, L. sativa produced shorter roots when exposed to its own root exudates. These results indicate kin recognition in these species. Further, the results show that L. sativa , a domesticated species, shares resources well with conspecifics. In contrast , L. serriola , a sparsely distributed species, is more competitive with conspecifics than with other species. We argue that artificial selection and domestication of L. sativa , from its progenitor L. serriola , modif y how the species interprets and respond to exudate cues from neighboring plants.