title: Love thy neighbour: facilitation through an alternative signalling modality in plants.
abstract: BACKGROUND
  Both competitive and facilitative interactions between species play a fundamental role in shaping natural communities. A recent study showed that competitive interactions between plants can be mediated by some alternative signalling channel, extending beyond those channels studied so far (i.e. chemicals, contact and light). Here, we tested whether such alternative pathway also enables facilitative interactions between neighbouring plant species. Specifically, we examined whether the presence of a 'good' neighbouring plant like basil positively influenced the germination of chilli seeds when all known signals were blocked. For this purpose, we used a custom-designed experimental set-up that prevented above- and below-ground contact and blocked chemical and light-mediated signals normally exchange by plants.
  
  
  RESULTS
  We found that seed germination was positively enhanced by the presence of a 'good' neighbour, even when the known signalling modalities were blocked, indicating that light, touch or chemical signals may not be indispensible for different plant species to sense each other's presence.
  
  
  CONCLUSIONS
  We propose that this alternative signalling modality operates as a general indicator of the presence of heterospecifics, enabling seeds to detect and identify a neighbour prior to engaging in a more finely-tuned, but potentially more costly, response.
authors: Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, WA 6009, Australia. monica.gagliano@uwa.edu.au
authors: Monica
authors: M
authors: Gagliano
authors: Michael
authors: M
authors: Renton
mesh_terms: D002212:Capsicum / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects; D017753:Ecosystem; D018525:Germination / Q000528:radiation effects; D008027:Light; D018649:Ocimum basilicum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects
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