User:Alexjustdoit/sandbox

A growing number of plants in recent years have been shown to distinguish kin and non-kin roots and signals in their environment. This is a further development from self and non-self recognition, in that we are seeing plants actively alter their behavior in an altruistic manner. Current research done by Karban et al. indicates that Artemisia tridentata responds more strongly to volatile signals from not only clones, but also close genomic relatives when compared to distant relatives and strangers. The herbivory induced volatiles triggered closely related plants to prepare for potential herbivory at a greater level than distant relatives. Chemical signals from roots have similarly been shown to mediate kin recognition in Deschampsia caespitosa when exposed to exudates from a variety of related and unrelated plants. Exudates were collected from siblings, D. caespitosa within the same community, a different species of plants within the community, D. caespitosa from another population, and a different species from a different community. The isolated exudates were then applied to the soil of seedling D. caespitosa. Root length density averaged 77% greater when exposed to unrelated chemical exudates over siblings. However, changes due to exudate application were not wholly localized, with some increased branching throughout the whole root system. A very similar experiment by Biedrzycki et al. finds that newly germinated seedlings in a sterile and highly controlled environment exhibit recognition toward root exudates, concluding that a soluble chemical exudate contains identity cues rather than any direct communication between plant roots. The immediate implications of this are obvious, plants can act selectively to improve the fitness of the species, at least within a community, but there may be other uses as well. File et al. showed that kinship recognition could play a role in mycorrhizal symbiosis. When Ambrosia artemisiifolia L. were grown in pairs and controlled for soil nutrients, mycorrhizal (Glomus intraradices) colonization, and growth was heavily dependent on the relatedness of the two individuals. Interestingly, the authors found no evidence of kinship recognition between the plants themselves, and postulate that the plasticity of the mycorrhizal symbiosis is itself the mechanism by which the two plants engage in kinship recognition.