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Jak anatomické a ekofyziologické charakteristiky podrostních bylin temperátních doubrav souvisí s jejich reakcí na sucho
Joura, Libor
Trees modify the environmental conditions for the growth of the shrub and herb layer. Nowadays, the tree layer in forest stands is changing at an unprecedented speed due to the influence of management and the influence of increasing natural mortality. Dense forest stands are considered a refuge for herbs from increased temperature due to global climate change. On the other hand, the surface temperature of leaves in thinned forest stands is indeed higher, but it also gives the possibility of active defense against drought or pathogens. In the diploma thesis, the effect of drought stress and lack of sunlight on anatomical parameters and their correlation with physiology was investigated in selected species of understory herbs growing in temperate oak forests, specifically in the Asarum europaeum L. and Hepatica nobilis Schreb. As a result of drought stress, Asarum europaeum experienced changes in the size of the xylem area of the petiole and the total area of the lumen of the petiole vessels. Furthermore, in the size of the surface area of the vessel lumen, which also changed due to the lack of sunlight. Drought stress had a significant effect on the size of the leaf area in the Asarum europaeum. In the Hepatica nobilis, drought stress had an effect mainly on the diameter of the lumen of the vessels, where stressed plants had a larger diameter of the lumen of the vessels. Drought stress also had a significant effect on the number of vessels in both species. The effect of drought and lack of sunlight had no significant effect on the observed correlations between anatomical and ecophysiological parameters. The Asarum europaeum approaches an isohydric survival strategy. It has a higher degree of stomatal regulation, forms a more efficient but sparser xylem due to a higher diameter of the lumen of the vessels and a larger area of the xylem of the petiole. Hepatica nobilis also forms a large vessel lumen diameter, but the xylem is characterized by lower hydraulic conductivity. It therefore forms a safer and denser xylem, corresponding to an anisohydric strategy. The herbaceous layer carries considerable ecological importance for the structure and function of forest ecosystems. It would be beneficial to perceive the herbaceous and tree layer as a more connected and compact unit. Forest management should consider the importance of the herb layer and also its demands in terms of light and water availability. Trees will thus benefit from the contribution of herbs from the point of view of better nutrient dynamics, the ability to moderate soil erosion or from improving the flow of water through the forest floor.
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Comparison of leaf area index dynamics and radiation use efficiency of C3 crops in the Czech Republic
Tripathi, Abishek ; Pohanková, Eva ; Trnka, Miroslav ; Klem, Karel
Leaf area index (LAI) and radiation use efficiency (RUE) are key parameters for plant growth and productivity.\nBecause of irregularities in weather conditions, accurate estimation of crop production requires\nunderstanding relationships between weather, LAI, RUE, and final production. It is thus important to\nstudy how the LAI dynamics, leaf area duration (LAD), and RUE are related to aboveground biomass production\nfor different crops. In our study, we compared aboveground dry mass production, LAI dynamics,\nRUE, and LAD in three C3 crops (spring barley [SB], winter wheat [WW], and oilseed rape [OSR]) in the\nCzech Republic. LAI was measured on the basis of transmitted photosynthetically active radiation, LAD\nwas calculated by counting the number of days in the growing season, RUE was measured using Beer’s\nlaw, and the aboveground dry mass was estimated at the time of harvest. Results of our study showed high\nbiomass production and RUE in SB while there was highest maximum LAI (LAImax) and LAD in OSR. We\nconcluded that LAI dynamics or LAImax do not fully reflect the crop production and that RUE may be considered\nas a better indicator for aboveground dry mass production.
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Guideline for leaf area index estimation in non-mixed forest tree stands
Pokorný, Radek
This guideline introduces theory and methodological approaches for LAI estimation in forest stands, especially those which are user-friendly in the field as well as sufficiently accurate. These approaches include indirect methods, which use instruments with optical sensors. This guideline fills the gaps in the information given in the instruction manuals to these instruments. It gives a detailed description of how to assess whether the current conditions for LAI measurement are suitable, how to establish a grid of measurement points in a stand and what corrections to apply, etc. in order to obtain the desired value of LAI effectively and accurately.
Fulltext: content.csg -  PDF
Plný tet: Stanovení indexu listové plochy v nesmíšených porostech lesních dřevin_metodika_Pokorný R. - PDF
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ECOLOGY APPLICATIONS IN THE GLASSHOUSE WITH THE SOLAR GRIDS
LESKOVCOVÁ, Martina
This Bachelor´s thesis is concerned with an observation of plants, especially generic beans (Phaseolus vulgaris L.), which were grown in front of varicoloured walls of greenhouse with solar rasters four years ago. It was supposed, according to a way of reflected solar radiation from the coloured walls, a different growth ability of plants in regard for leaf areas, a gross biomass, some of growth parameters of leaves and a photosyntetic rate as well. There was not discovered any possibility of influence of the walls relating to leaf areas, a weight of biomass and the photosyntetic rate. The influence was only set down in some of the parameters of leaves.
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