Touchy feely Arabidopsis

Arabidopsis thaliana Plants in dense veget­a­tion com­pete for resources, includ­ing light, and optim­ize their growth based on neigh­bor detec­tion cues. The best stud­ied of such beha­vi­ors is the shade-avoidance syn­drome that pos­i­tions leaves in optim­ally lit zones of a veget­a­tion. Although prox­im­ate veget­a­tion is known to be sensed through a reduced ratio between red and far-red light, we show here through com­pu­ta­tional mod­el­ing and manip­u­lat­ive exper­i­ments that leaves of the rosette spe­cies Arabidopsis thali­ana first need to move upward to gen­er­ate suf­fi­cient light reflec­tion poten­tial for sub­sequent occur­rence and per­cep­tion of a reduced red to far-red ratio. This early hyponastic leaf growth response is not induced by known neigh­bor detec­tion cues under both cli­mate cham­ber and nat­ural sun­light con­di­tions, and we identify a unique way for plants to detect future com­pet­it­ors through touch­ing of leaf tips. This sig­nal occurs before light sig­nals and appears to be the earli­est means of above-ground plant–plant sig­nal­ing in hori­zont­ally grow­ing rosette plants.”

Plant neigh­bor detec­tion through touch­ing leaf tips pre­cedes phyto­chrome sig­nals. PNAS USA 20 August 2012, doi: 10.1073/pnas.12054371


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