Timing is everything in ecology, and because plants provide the foundation for most land-based food webs, the timing of their activities profoundly orchestrates the majority of ecological interactions. Most photosynthetic and growth processes are under circadian control, but many additional processes--approximately 30-40% of all genes—are under circadian control, and yet the Darwinian fitness impact of being “in synch” with the environment has not been systematically studied for any organism.We have developed a toolbox for a native tobacco plant, Nicotiana attenuata, that allows us to “ask the plant” which genes, proteins or metabolites are regulated in particular plant-mediated ecological interactions; identify “the genes that matter” for a given interaction; silence or ectopically express these genes, and conduct field releases with the transformed plants at a nature preserve in the Great Basin Desert to rigorously test hypotheses of gene function. By taking advantage of both our understanding of what it takes for this plant to survive in nature, and the procedures established to disentangle the skein of subtle interactions that determine its performance, we will systematically examine the importance of synchronous entrained endogenous rhythms at all life stages: longevity in the seed bank, germination, rosette growth, elongation, flowering and senescence. Specifically, we propose to silence a key components (starting with NaTOC1) of the plant’s endogenous clock to shorten the plant’s circadian rhythm, both constitutively and with strong dexamethasone-inducible promoters, at all life stages. With a combination of real-time phenotype imaging, metabolite and transcriptome analysis, and ecological know-how, the research will reveal how plants adjust their physiologies to the ever-changing panoply of environmental stresses with which they must cope; by creating arrhythmic plants, we will understand why so many processes are under circadian control.