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dc.contributor.advisorDillenburg, Lucia Rebellopt_BR
dc.contributor.authorJost, Monique Salardipt_BR
dc.date.accessioned2022-06-11T05:02:33Zpt_BR
dc.date.issued2019pt_BR
dc.identifier.urihttp://hdl.handle.net/10183/240128pt_BR
dc.description.abstractDepending on light availability, plants may adopt two antagonistic developmental patterns: photomorphogenesis in the light and skotomorphogenesis in the darkness. Skotomorphogenesis is characterized by the use of the reserves to promote mostly stem elongation in order to seek light, while delaying leaf production and development of the photosynthetic apparatus. Despite being well described in angiosperms, it is poorly addressed in gymnosperms. This study aims to characterize this process in Araucaria angustifolia, an endangered conifer from South America, by imposing darkness to their aerial environments and forcing shoots to initially develop belowground. Seeds were either sown close to the soil surface or deep into the soil. Half of these seeds had access to light and half remained in the darkness. These plants were grown for 147 days, and then measured for several growth parameters. There was an increased investment on stem elongation at the expenses of leaf production when light was not available. Leaves that developed in the dark were smaller, lighter, and more widely spaced than those that developed in the light. Photomorphogenic shoots were greener and accumulated much more chlorophylls than the whitish skotomorphogenic ones. Darkness had no effect in the rate of consumption of seed reserves and on total dry mass accumulation. True leaves were not produced when shoots developed belowground, and these shoots were colorless, wider and invested more in dry mass in order to elongate when compared to shoots that extended aboveground. Skotomorphogenesis in A. angustifolia was characterized by a developmental pattern that increases the chances of plants reaching for light while saving as much carbon as possible. Darkness imposed by seed burial was also associated to the physical resistance offered by the soil, thus altering some aspects of the skotomorphogenesis.en
dc.format.mimetypeapplication/pdfpt_BR
dc.language.isoengpt_BR
dc.rightsOpen Accessen
dc.subjectDesenvolvimentopt_BR
dc.subjectDevelopmenten
dc.subjectPinheiropt_BR
dc.subjectDarknessen
dc.subjectAraucaria angustifoliapt_BR
dc.subjectBrazilian pineen
dc.titleCaracterização da escotomorfogênese em plântulas de araucaria angustifolia (araucariaceae)pt_BR
dc.typeTrabalho de conclusão de graduaçãopt_BR
dc.identifier.nrb001112364pt_BR
dc.degree.grantorUniversidade Federal do Rio Grande do Sulpt_BR
dc.degree.departmentInstituto de Biociênciaspt_BR
dc.degree.localPorto Alegre, BR-RSpt_BR
dc.degree.date2019pt_BR
dc.degree.graduationBiotecnologiapt_BR
dc.degree.levelgraduaçãopt_BR


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