|
|
Auxin transport in algae
Skokan, Roman ; Petrášek, Jan (advisor) ; Bíšová, Kateřina (referee)
Phytohormone auxin plays an important role in regulating plant development. Directional (polar) cell-to-cell auxin transport creates auxin gradients within plant tissues, which trigger a specific developmental response. The vast majority of available data concerns angiosperms. Lower land plants have been much less explored in this regard, but the important auxin-related mechanisms (including polar auxin transport) are already present in mosses. To uncover the origins of auxin action, one must focus on green algae, especially of clade Streptophyta, which are the direct ancestors of all land plants. In this study, the possible effects of auxins, both native and synthetic, were investigated on two algae: basal, unicellular Chlorella lobophora and advanced, filamentous Spirogyra sp. The latter received comparably more attention, since it belongs to a clade now acknowledged as a sister group to land plants. Chlorella lobophora culture growth was irresponsive to synthetic auxin NAA. The average Spirogyra sp. cell length was, however, changed by auxins at high concentrations. By conducting accumulation assays of radioactively labelled auxins and HPLC analysis, auxin metabolism and transport was investigated in Spirogyra sp. This alga was able to metabolize the plant-native IAA, but not synthetic auxins...
|
|
|
Využitie muntantov ramosus pri štúdiu fytohormonálnej regulácie vetvenia stonky u hrachu
Polko, Peter
This thesis deals with effect of phytohormonal application on apical dominance, stem anatomy and expression of PsPIN1 in garden pea (Pisum sativum) variety Paloma and from this variety derived mutant rms4. In this thesis effect of decapitation, exogenous application of auxin (IAA, in a form of lanoline paste) and strigolactone (GR24, in a form of admixture in nutrient solution) on growth activity of axillary buds from nodes 1st to 4th was studied. After decapitation (above 4th node) "wild-type" plants reacted by increased intensity of axillary buds growth in almost all observed nodes and application of IAA inhibited growth of axillary buds to level of intact plants. In rms4 plants response on decapitation was only observed in axillary buds of the 4th node along with there was observation of insensivity to IAA in other observed nodes. GR24 inhibited growth of axillary buds in a small extent in "wild-type" plants and in rms4 mutants there was no observation of this inhibitory effect of strigolactone. Furthermore this thesis deals with effect of decapitation on [3H] - IAA transport from axillary bud in to young plants stems. Polar auxin transport capacity in stem is slightly higher in rms4 mutant and after decapitation axillary buds exported more auxin compared to "wild-type" plants. De novo vascular differentiation was observed 5 days after application of IAA in stem of both genotypes. Expression of PsPIN1 increased after IAA treatment both in Paloma and in rms4 mutant. This increase was higher in rms4 mutant compared to variety Paloma.
|
|
|
Auxin transport in algae
Skokan, Roman ; Petrášek, Jan (advisor) ; Bíšová, Kateřina (referee)
Phytohormone auxin plays an important role in regulating plant development. Directional (polar) cell-to-cell auxin transport creates auxin gradients within plant tissues, which trigger a specific developmental response. The vast majority of available data concerns angiosperms. Lower land plants have been much less explored in this regard, but the important auxin-related mechanisms (including polar auxin transport) are already present in mosses. To uncover the origins of auxin action, one must focus on green algae, especially of clade Streptophyta, which are the direct ancestors of all land plants. In this study, the possible effects of auxins, both native and synthetic, were investigated on two algae: basal, unicellular Chlorella lobophora and advanced, filamentous Spirogyra sp. The latter received comparably more attention, since it belongs to a clade now acknowledged as a sister group to land plants. Chlorella lobophora culture growth was irresponsive to synthetic auxin NAA. The average Spirogyra sp. cell length was, however, changed by auxins at high concentrations. By conducting accumulation assays of radioactively labelled auxins and HPLC analysis, auxin metabolism and transport was investigated in Spirogyra sp. This alga was able to metabolize the plant-native IAA, but not synthetic auxins...
|
guest ::
