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The influence of roots on the chemical properties of the apoplast and the rhizosphere
Puldová, Kristýna ; Fendrych, Matyáš (advisor) ; Šámalová, Markéta (referee)
Chemical properties of the apoplast and rhizosphere are crucial for plant development and its overall well-being. Apoplast includes space outside the plasma membrane and its content, such as gas, water, and solutes. Changes in apoplast properties significantly influence various processes. One of them is cellular growth - the pH-dependent extension of cell walls. The rhizosphere is the soil environment near and under the influence of roots. It is characterised by abiotic factors like the availability of nutrients and toxic compounds. It is also a space with a high representation of microbiome communities. Plants can significantly influence the chemical properties of both apoplast and rhizosphere to improve their growth conditions. This thesis summarises the most important mechanisms of plants' roots that change these chemical properties, focusing on the model plant Arabidopsis thaliana. It shows how and where these mechanisms intersect and in which way they influence each other. Emphasis is placed on the process of growth regulation and mechanisms of increasing nutrient availability. Keywords: apoplast, rhizosphere, H+ ATPase, root growth, rhizodeposition, root exudates, nutrients, microbiome
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Visualization of root apoplastic pH in plants
Wernerová, Daša ; Fendrych, Matyáš (advisor) ; Paris, Nadine (referee)
Plant oriented movements, or tropisms allow the plant to actively respond to environmental stimuli to get more light, better access to nutrients and to grow roots deeper into the soil. Gravitropism drives the growth of roots along the gravity vector. Perception of gravity is triggered by the sedimentation of statoliths in columella root cap, but the exact signalling pathway behind this process is not known. Perception of gravity results in an unequal redistribution of the phytohormone auxin in the outer cell layers which leads to different rate of growth on the root's upper and lower side and bending of the root. The changes in auxin redistribution are accompanied by changes in apoplastic pH. Knowing an exact pattern of these pH changes could shed light on the mechanisms laying behind the gravitropic response pathway. While microelectrodes can be used to measure pH precisely, they are not suitable for the long-term imaging of growing roots. In the past few years, several pH sensitive dyes and genetically encoded sensors emerged. These can be used for long-term live in vivo imaging of pH changes in growing roots. In this thesis, I analysed the performance of several published pH sensitive genetically encoded sensors and available dyes in the roots of Arabidopsis thaliana. I observed that dyes varied...
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Visualization of root apoplastic pH in plants
Wernerová, Daša ; Fendrych, Matyáš (advisor) ; Paris, Nadine (referee)
Plant oriented movements, or tropisms allow the plant to actively respond to environmental stimuli to get more light, better access to nutrients and to grow roots deeper into the soil. Gravitropism drives the growth of roots along the gravity vector. Perception of gravity is triggered by the sedimentation of statoliths in columella root cap, but the exact signalling pathway behind this process is not known. Perception of gravity results in an unequal redistribution of the phytohormone auxin in the outer cell layers which leads to different rate of growth on the root's upper and lower side and bending of the root. The changes in auxin redistribution are accompanied by changes in apoplastic pH. Knowing an exact pattern of these pH changes could shed light on the mechanisms laying behind the gravitropic response pathway. While microelectrodes can be used to measure pH precisely, they are not suitable for the long-term imaging of growing roots. In the past few years, several pH sensitive dyes and genetically encoded sensors emerged. These can be used for long-term live in vivo imaging of pH changes in growing roots. In this thesis, I analysed the performance of several published pH sensitive genetically encoded sensors and available dyes in the roots of Arabidopsis thaliana. I observed that dyes varied...
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