2.7.2. Plant Kin Recognition

Kin recognition is simply the ability of an individual to distinguish the relationship between genetically close related kin and non-kin. The kin recognition of plants has very important ecological and evolutionary significance. Increasing evidence shows that plants' recognition of neighboring allogenous and heterogeneous plants is mostly mediated by chemicals [131,132]. When plants are attacked by herbivores, they will emit volatile signals to surrounding plants. Some plants, such as *A. tidentata*, suffered less damage than other plants that receive volatile signals from non-self-wounds [133,134]. This shows that VOCs play a role in plant self- and non-self-recognition. Because VOCs are the simplest and fastest chemical signal that can send to neighboring plants, plant recognition of volatiles helps plants to establish corresponding response strategies in the early stages of competition. This can avoid wasting resources in the competition between self and relatives as much as possible [130]. After a series of studies recently, although the kin recognition of plants is ubiquitous, most studies show that some plants do not have kin recognition behaviors in order to avoid meaningless competition [27,135–137]. Plants' kin recognition has always been a hot topic in the study of behavioral ecology and evolution. From the perspective of genetic recognition, it is of great theoretical and practical significance to re-examine the ecological interaction of individual crops and groups and the environment.
