Plants are sessiles. So they have to developp many strategies to cope with physical, chemical or biological stimuli which appear in their environment. Our study aims to understand how plant can interact with those stimuli and which vectors facilite this communication. First, in-vitro experimentation was developed by a group of American students in order to identify four components responsible of the communication between plants. Then, we developed models to predict the nature of the signal based on the response time observed in the american’s experiment. The results showed that it is possible for all plants continuously emit similar signals in amounts proportional to the quality of their environment and thus create a signal gradient characterizing the soil quality gradients but this is unlikely from an evolutionary point of view because it means that the plant spends energy to increase competition in his environment