Diurnal photoperiods and rhythmicity of the phototropic bending response in hypocotyls of sunflower, Helianthus annuus L. seedlings
Research on phototropic (PT) bending in sunflower (Helianthus annuus L. cv. Kondi (Syngenta)) seedling hypocotyls presented herein focused on a comparison of diurnal and free-running photoperiods with the aim of explaining the development of diurnal rhythmicity. PT bending magnitudes and lag phase d...
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University of Belgrade, University of Novi Sad
2021-01-01
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doaj-3de114be9b414afc97ea693fab4bb1982021-07-19T07:08:31ZengUniversity of Belgrade, University of Novi SadArchives of Biological Sciences0354-46641821-43392021-01-0173223724610.2298/ABS210205018V0354-46642100018VDiurnal photoperiods and rhythmicity of the phototropic bending response in hypocotyls of sunflower, Helianthus annuus L. seedlingsVinterhalter Dragan0https://orcid.org/0000-0001-9324-1767Vinterhalter Branka1https://orcid.org/0000-0001-8502-7285Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, SerbiaDepartment of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, SerbiaResearch on phototropic (PT) bending in sunflower (Helianthus annuus L. cv. Kondi (Syngenta)) seedling hypocotyls presented herein focused on a comparison of diurnal and free-running photoperiods with the aim of explaining the development of diurnal rhythmicity. PT bending magnitudes and lag phase duration exhibited strong daily rhythmicity in all diurnal photoperiods, contrasting with the uniform PT bending response to constant light (CL) conditions. Plants had a daytime maximum for PT bending magnitudes in experiments starting around midday and a minimum in the dark period in those starting 4 h after dusk. Plants could compensate for large differences in the daytime duration of diurnal photoperiods. They required the first 4 h of darkness to recover and synchronize the PT bending and to start increasing the magnitudes of PT bending. The daily pattern of lag phase duration changes was similar but inverted, showing that synchronization also occurred during nighttime. Darkness was not required for PT bending under CL conditions, however, during diurnal photoperiods it enabled the establishment of diurnal rhythmicity and synchronized changes in PT bending capacity to occur when needed, providing maximal values at midday and minimal during the nighttime. Under prolonged duration of daytime corresponding to the start of CL condition, plantlets rapidly abandoned circadian regulation, their PT bending response becoming arrhythmic.http://www.doiserbia.nb.rs/img/doi/0354-4664/2021/0354-46642100018V.pdfphototropismsunflowerphotoperiodsdiurnal rhythmicitycircadian regulation |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Vinterhalter Dragan Vinterhalter Branka |
spellingShingle |
Vinterhalter Dragan Vinterhalter Branka Diurnal photoperiods and rhythmicity of the phototropic bending response in hypocotyls of sunflower, Helianthus annuus L. seedlings Archives of Biological Sciences phototropism sunflower photoperiods diurnal rhythmicity circadian regulation |
author_facet |
Vinterhalter Dragan Vinterhalter Branka |
author_sort |
Vinterhalter Dragan |
title |
Diurnal photoperiods and rhythmicity of the phototropic bending response in hypocotyls of sunflower, Helianthus annuus L. seedlings |
title_short |
Diurnal photoperiods and rhythmicity of the phototropic bending response in hypocotyls of sunflower, Helianthus annuus L. seedlings |
title_full |
Diurnal photoperiods and rhythmicity of the phototropic bending response in hypocotyls of sunflower, Helianthus annuus L. seedlings |
title_fullStr |
Diurnal photoperiods and rhythmicity of the phototropic bending response in hypocotyls of sunflower, Helianthus annuus L. seedlings |
title_full_unstemmed |
Diurnal photoperiods and rhythmicity of the phototropic bending response in hypocotyls of sunflower, Helianthus annuus L. seedlings |
title_sort |
diurnal photoperiods and rhythmicity of the phototropic bending response in hypocotyls of sunflower, helianthus annuus l. seedlings |
publisher |
University of Belgrade, University of Novi Sad |
series |
Archives of Biological Sciences |
issn |
0354-4664 1821-4339 |
publishDate |
2021-01-01 |
description |
Research on phototropic (PT) bending in sunflower (Helianthus annuus L. cv. Kondi (Syngenta)) seedling hypocotyls presented herein focused on a comparison of diurnal and free-running photoperiods with the aim of explaining the development of diurnal rhythmicity. PT bending magnitudes and lag phase duration exhibited strong daily rhythmicity in all diurnal photoperiods, contrasting with the uniform PT bending response to constant light (CL) conditions. Plants had a daytime maximum for PT bending magnitudes in experiments starting around midday and a minimum in the dark period in those starting 4 h after dusk. Plants could compensate for large differences in the daytime duration of diurnal photoperiods. They required the first 4 h of darkness to recover and synchronize the PT bending and to start increasing the magnitudes of PT bending. The daily pattern of lag phase duration changes was similar but inverted, showing that synchronization also occurred during nighttime. Darkness was not required for PT bending under CL conditions, however, during diurnal photoperiods it enabled the establishment of diurnal rhythmicity and synchronized changes in PT bending capacity to occur when needed, providing maximal values at midday and minimal during the nighttime. Under prolonged duration of daytime corresponding to the start of CL condition, plantlets rapidly abandoned circadian regulation, their PT bending response becoming arrhythmic. |
topic |
phototropism sunflower photoperiods diurnal rhythmicity circadian regulation |
url |
http://www.doiserbia.nb.rs/img/doi/0354-4664/2021/0354-46642100018V.pdf |
work_keys_str_mv |
AT vinterhalterdragan diurnalphotoperiodsandrhythmicityofthephototropicbendingresponseinhypocotylsofsunflowerhelianthusannuuslseedlings AT vinterhalterbranka diurnalphotoperiodsandrhythmicityofthephototropicbendingresponseinhypocotylsofsunflowerhelianthusannuuslseedlings |
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