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Effect of artificial light at night on ecophysiological functions of plants
Ležal, Lukáš ; Konrádová, Hana (advisor) ; Lhotáková, Zuzana (referee)
Artificial light at night, as a significant source of anthropogenic pollution, has long been overlooked, both among the general public and in the scientific community as well as at the legislature level. Steps to reduce the negative impacts of artificial light at night have been taken late and to an insufficient extent, and it was the low general awareness that was one of the motivations for the bachelor thesis on this topic. Plants are a group of organisms that receive less attention than, for example, humans, although they far exceed them in ecological importance. Artificial light at night has the potential to alter the composition of plant communities and the food webs that are linked to them, of which humans are at the top. This is done by shifting plant phenological phases, disrupting the natural perception of day and night, modifying growth patterns and morphological characteristics, increasing irradiance stress or reducing the efficiency of photosynthesis. It is through a comprehensive knowledge of the interaction of plants with artificial light at night that society can effectively protect nature and introduce the necessary new standards and technologies to ensure sustainable development.
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Circadian rhythms and photoperiodism in insects
STEHLÍK, Jan
In this thesis we present experimental data and discuss circadian rhythm regulation in the housefly, Musca domestica. Our findings suggest that, although differences in the mechanisms of circadian rhythm regulation between Musca domestica and Drosophila melanogaster are not as fundamental as was originally expected, they still provide interesting insight into the evolution of biological clocks. We also studied possible involvement of one of the circadian clock genes, timeless, in photoperiodic induction of diapause in a drosophilid fly, Chymomyza costata. We found the transcription of tim gene to be strongly disrupted in CNS of npd-mutant (non-photoperiodic-diapause) larvae. Analysis of genomic structure of tim gene revealed that the promoter of timelessnpd allele carries a large deletion, a possible cause of disruption of photoperiodic calendar function in npd-mutant larvae of C. costata.
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The photoperiodism and hibernation
Pařezová, Lucie ; Bendová, Zdeňka (advisor) ; Weissová, Kamila (referee)
Many organisms living in seasonal environments use annual changes in the length of the day for timing of their responses, such as reproduction, migration or hibernation. Hibernation allows animals to survive difficult periods associated particularly with cold temperatures and lack of food resources. This adaptation requires many physiological, morphological and behavioral changes. Some of these changes take longer, so their right timing is crucial. For most hibernators in temperate regions shortening of the photoperiod is the most reliable signal for initiation of these changes. This work describes the transduction of photoperiodic information to the melatonin signal, its effects in the pars tuberalis and the significance of this structure in seasonal physiology. A more detailed description is devoted to hibernation, and in the last chapter there is briefly mentioned photoperiodism in nonhibernating organisms. Powered by TCPDF (www.tcpdf.org)
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The photoperiodism and hibernation
Pařezová, Lucie ; Bendová, Zdeňka (advisor) ; Weissová, Kamila (referee)
Many organisms living in seasonal environments use annual changes in the length of the day for timing of their responses, such as reproduction, migration or hibernation. Hibernation allows animals to survive difficult periods associated particularly with cold temperatures and lack of food resources. This adaptation requires many physiological, morphological and behavioral changes. Some of these changes take longer, so their right timing is crucial. For most hibernators in temperate regions shortening of the photoperiod is the most reliable signal for initiation of these changes. This work describes the transduction of photoperiodic information to the melatonin signal, its effects in the pars tuberalis and the significance of this structure in seasonal physiology. A more detailed description is devoted to hibernation, and in the last chapter there is briefly mentioned photoperiodism in nonhibernating organisms. Powered by TCPDF (www.tcpdf.org)
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