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Transport of humic substances through plant cuticle
Hývnarová, Lucie ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
In my bachelor thesis I deal with the transport of lignohumate through the plant cuticle. Specifically, I deal with transport through the leaf cuticle, which is divided into upper and lower cuticles. The difference between the upper and lower cuticles is that the lower cuticle contains vents. To study this transport, it was first necessary to separate the cuticles from the leaf. I used two methods of chemical isolation, which is more aggressive, but it is less time consuming (3 days) and a chemical method that is softer but takes longer (about 6 weeks). I created diffuse vapors from the separated cuticles, which consist of a source gel, where the lignohumate agarose gel and the intake gel are purely agarose gel. In these diffuse pairs, the time profile of the concentration profiles was monitored by UV-VIS spectrometry for 10 days and diffusion of the source gel into the uptake gel was monitored. Based on Fick's laws and their solution for diffusion in a pair of infinite media, the diffusion coefficient of lignohumate in the hydrogel was determined and the effect of isolated cuticles as a barrier at the interface between the two hydrogels was assessed. The results show that lignohumate diffuses best through the lower cuticle, which was separated by a chemical isolation method. Chemical isolation is much more drastic than the enzymatic method because zinc chloride is used, which is corrosive and damages cellulose. Thus, in this isolation, the cuticle structure is damaged and thereby reduced, resulting in increased membrane permeability.
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Plant cuticle
Voloshina, Mariia ; Schwarzerová, Kateřina (advisor) ; Synek, Lukáš (referee)
The cuticle is a lipidic structure covering plant aerial organs, providing mechanical rigidity and acting as a protective barrier. It contains the cutin polyester and waxes, which are derived from very-long-chain fatty acids. These compounds are synthesised in two separate pathways. The cuticular biosynthetic machinery is incredibly complex and employs a multitude of enzymes, some of which are functionally redundant, are present in different tissues or catalyse reactions with substrates of various chain lengths. The mechanisms of how these compounds are transported and how the cuticle is assembled rely on ABC transporters, LTP lipid carrier proteins, cutin synthases, and cutinsomes. Knowledge of these highly dynamic processes is very fragmented and the integrated model of cutin synthesis is yet to be elucidated. A tight connection between the cuticle and the cell wall, conventionally seen as two separate entities, has also been implied. The complexity of these mechanisms is also reflected in their transcriptional and post-transcriptional regulation. While SHINE and MIXTA-like transcriptional factors and the WW-domain protein CFL1 regulate the cuticle's synthesis throughout a plant's development, ABA-dependent MYB transcriptional factors are important during abiotic stress. Recent research also...
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Transport of humic substances through plant cuticle
Hývnarová, Lucie ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
In my bachelor thesis I deal with the transport of lignohumate through the plant cuticle. Specifically, I deal with transport through the leaf cuticle, which is divided into upper and lower cuticles. The difference between the upper and lower cuticles is that the lower cuticle contains vents. To study this transport, it was first necessary to separate the cuticles from the leaf. I used two methods of chemical isolation, which is more aggressive, but it is less time consuming (3 days) and a chemical method that is softer but takes longer (about 6 weeks). I created diffuse vapors from the separated cuticles, which consist of a source gel, where the lignohumate agarose gel and the intake gel are purely agarose gel. In these diffuse pairs, the time profile of the concentration profiles was monitored by UV-VIS spectrometry for 10 days and diffusion of the source gel into the uptake gel was monitored. Based on Fick's laws and their solution for diffusion in a pair of infinite media, the diffusion coefficient of lignohumate in the hydrogel was determined and the effect of isolated cuticles as a barrier at the interface between the two hydrogels was assessed. The results show that lignohumate diffuses best through the lower cuticle, which was separated by a chemical isolation method. Chemical isolation is much more drastic than the enzymatic method because zinc chloride is used, which is corrosive and damages cellulose. Thus, in this isolation, the cuticle structure is damaged and thereby reduced, resulting in increased membrane permeability.
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