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Lignin and lignification mechanisms
Gargoš, Ondřej ; Tylová, Edita (advisor) ; Schwarzerová, Kateřina (referee)
Lignin is an essential compound of all vascular plants. Recent studies have also shown its presence in non-vascular plants. Lignin is important for plant growth and development, provides a mechanical support to plant tissues and is also a major player in the response of plants to various stresses. Lignin is an aromatic heteropolymer and comprises classical lignin units - guaiacyl (G), syringyl (S) and p-hydroxyfenyl (H). The amount and ratio of these lignin units varies among plant species, organs and cell types. Nontraditional monomer units that can be deposited in lignin also increase the variety of lignin. Lignification, i.e. the formation and deposition of lignin, is a complex and precisely controlled process involving the synthesis of monolignols in the cytoplasm, their transport into the cell wall and subsequent polymerization. A number of enzymes are involved in the lignification process, and recent studies are gradually revealing the mechanisms of lignification regulation in various cells of plant body. This bachelor thesis summarizes the knowledge of the importance, synthesis and deposition of lignin, and also compares the mechanisms regulating lignification in different types of plant cells - tracheary elements, sclerenchyma and endodermal cells. An interesting phenomenon of lignification...
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Mechanisms of exodermal response to nutrient availability in the environment
Gargoš, Ondřej ; Tylová, Edita (advisor) ; Kummerová, Marie (referee)
in English The apoplastic barriers of the root (endodermis and exodermis) represent an important regulatory mechanism for the uptake of water and nutrients from the environment, ensuring its selectivity. In addition, both layers respond to stress factors by altering its rate and degree of cell wall modification, which affects the transport properties of the root and represents adaptive plants to high heterogeneity of the soil environment. Apoplastic barriers also respond to the availability of mineral nutrients. This issue has recently been intensively studied and a number of ambiguities persist. Interestingly, the deficiency of some mineral nutrients stimulates the differentiation of barriers, while the deficiency of other mineral nutrients delays the differentiation. In addition, different plant species react differently to the deficiency of the same element. Another interesting aspect is the fact that the reaction of the endodermis and exodermis is localized and takes place mainly in that part of the root system which is directly exposed to the stress factor. This phenomenon has been observed with cadmium toxicity, but more recently with local nutrient deficiencies (nitrogen and potassium) in Zea mays. This diploma thesis deals with the functional significance of localized enhancing or delaying...
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Lignin and lignification mechanisms
Gargoš, Ondřej ; Tylová, Edita (advisor) ; Schwarzerová, Kateřina (referee)
Lignin is an essential compound of all vascular plants. Recent studies have also shown its presence in non-vascular plants. Lignin is important for plant growth and development, provides a mechanical support to plant tissues and is also a major player in the response of plants to various stresses. Lignin is an aromatic heteropolymer and comprises classical lignin units - guaiacyl (G), syringyl (S) and p-hydroxyfenyl (H). The amount and ratio of these lignin units varies among plant species, organs and cell types. Nontraditional monomer units that can be deposited in lignin also increase the variety of lignin. Lignification, i.e. the formation and deposition of lignin, is a complex and precisely controlled process involving the synthesis of monolignols in the cytoplasm, their transport into the cell wall and subsequent polymerization. A number of enzymes are involved in the lignification process, and recent studies are gradually revealing the mechanisms of lignification regulation in various cells of plant body. This bachelor thesis summarizes the knowledge of the importance, synthesis and deposition of lignin, and also compares the mechanisms regulating lignification in different types of plant cells - tracheary elements, sclerenchyma and endodermal cells. An interesting phenomenon of lignification...
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