Archiv Volume III

 

Šebánek, J.: History of the physiology of plant movements in view of research at Mendel University and other scientific institutions in Brno. Folia univ. agric. et silvic. Mendel. Brun., 2010, Vol. III, No. 1

In 1880, with his research into plant movements, which lasted half a century, Darwin initiated the path to the discovery of the plant hormone auxin. Coleoptiles of oat seedlings (Avena sativa) and other grasses growing towards a one-sided light source showed positive phototropism, i.e. they bended in the direction of the light. It is because the coleoptile on the dark side grows faster because more growth-stimulating auxin flows there. In coleoptiles or roots in horizontal position, due to gravitation, auxin flows to the lower side and this side of the coleoptile then grows faster and the coleoptile turns upwards (negatively gravitropic). However the root is very sensitive to auxin, and on the lower side auxin inhibits its growth and the root curves downwards (positively gravitropic). This explanation of tropisms formulated by Cholodny and Went in 1929 remained to be a hypothesis for 70 years only to be confirmed in the past decade on the basis of molecular biological methods, particularly in the model plant Arabidopsis thaliana. Perception of gravity in the root is due to the sedimentation of starch grains in the root cap as a result of the relocation of protein PIN3 to the lower side enabling the flow of auxin to this side. Protein ARG1, and abscisic acid, cytokinins and Ca2+ are also important. In terms of gravity the starch grains are also important in the coleoptile and stem and for the movement of PIN protein along with relocation of auxin to the lower side. In the case of phototropism Bruinsma and Hasegawa assumed that the accumulation of inhibitors on the side turned to the light source is important and in some cases they dispute the relocation of auxin.

The monograph also devotes attention to nasties, particularly to thigmonasty in Mimosa pudica. Investigations into its stimulating substance led to the discovery of a new group of plant hormones, so-called turgorins. Research into thigmonasty was advanced by the discovery of TCH genes in Arabidopsis. The starchless mutants of this model plant made it possible to study the dependence of circumnutation movements on gravitation.

The two Czech schools of botany in Brno went down in the history of understanding plant movements; the plant hormone school founded by Prof. Dostál at the present Mendel University and the cinematographic botany school of J. Calábek, professor of the same University. In Dostál's school plant movements were explored in order to obtain more profound information about plant morphogenesis. For instance the changes in the curving of the apical parts of the eyes in potato tubers (Solanum tuberosum) disclosed the relationship to stem apical dominance. In a similar way the curving reactions of hypocotyl seedlings of flax (Linum usitatissimum) made it possible to learn the growth-regulating effects of cotyledons. Suitable applications of plant hormones helped to prove the hormonal nature of hook-like curvatures of the tips of pea seedlings (Pisum sativum) and flower stems of poppy (Papaver somniferum).

Calábek's school studied the autonomous (circumnutation) and twining movements of plants by means of film. Differences between the two were seen in the Ipomoea purpurea and Humulus lupulus plants, the stem tips at first curving in ellipsoidal rotations to the right or left. When they turned into twining movements the stem turned downwards to a horizontal position and began a circular trajectory; in hop always to the right and in Ipomoea to the left. The acceleration of growth did not affect the speed of rotation; it is therefore an independent phenomenon and not a mere accompanying phenomenon of growth. A one-sided light source disturbed the circumnutation rhythm in seedlings of pine (Pinus silvestris). The amplitudes of circumnutation movements of pine hypocotyls are much more marked than the movements of hypocotyls of spruce (Picea abies).

Keywords: hormonal essence of tropisms; tropisms and molecular biology; Arabidopsis thaliana; morphogenesis and plant movements; hook-like bending of stem tips; changing of circumnutation into twining movement

Martinková Kuchyňková, H.: Visual exposure: Calculation methodology of the landscape indicator in geographical information systems. Folia univ. agric. et silvic. Mendel. Brun., 2010, Vol. III, No. 2

In this paper, we deal with the selected landscape indicator of visual exposure and its possible use for evaluating some visual landscape characteristics. At the beginning we give a self-contained overview about two themes: at first, about landscape indicators and their use within the process of landscape character assessment and then about selected visual landscape characteristics and the possibilities of their evaluation within geographical information systems.

In this project, we deal in detail with the landscape indicator of visual exposure together with its use in practice. For this determination we prepare a simple program in the software ArcGIS Desktop 9.3, ArcInfo licence. Mentioned simple program called "model" was created by the arranging of several relevant tools in a row. Constructed model is possible to redistribute and re-use repeatedly for different case study areas.

This project, in which two alternatives of visual exposure were examined, was based on visibility analysis in geographical information systems. Two basic input layers are used here. There are digital surface model of the case study area and a huge amount of input points -- observer viewpoints. The two alternatives differ in the second input layer. A regular grid layer of viewpoints was used for alternative A, and viewpoints based on the actual use of frequented sites were used for alternative B.

With respect to the results of the two alternatives, the calculation of alternative A, based upon a regular grid of viewpoints, led to increased categories of higher visual exposure. In addition, alternative A also better reflected the actual landscape structure and also the selection of input viewpoints was not influenced by actual land use.

At the end the whole procedure was verified using the case study area of Frenstat pod Radhostem, in the Czech Republic. The visualization of the acquired results was done in 3-dimensional space using software ArcScene and was used for comparison with a photograph of the real conditions.

Keywords: landscape indikator; landscape character assessment; digital terrain model; ArcGIS Desktop; Frenstat pod Radhostem; Czech Republic

Balík, J.: Anthocyanin pigments in grapes and wines. Folia univ. agric. et silvic. Mendel. Brun., 2010, Vol. III, No. 3
This paper deals with the occurrence of anthocyanin pigments in grapes and about their importance for colour parameters of red and rosé wines. The author presents data about contents of anthocyanins in some selected varieties of Vitis vinifera L. and about anthocyanin composition in some selected interspecific hybrids. Anthocyanins are characterized with regard to their chemical structure, biosynthesis and properties. The author describes analytical methods and procedures of an instrumental evaluation of wine colouring. Changes of anthocyanin pigments and colour parameters of red and rosé wines are evaluated with regard to the applied technology of vinification of grapes and to the process of treatment and ageing of wine. The highest content of anthocyanin pigments was determined in grapes of the varieties Neronet, Dornfelder and Cabernet Moravia. The content of anthocyanin pigments was dependent on variety, vintage and health condition of grapes. Diglucosidic anthocyanins particularly malvidin-3,5-diglukoside was found out in grapes of interspecific hybrids Golubok, Kaberon, and Regent. Fermentative maceration of anthocyanins from grape skins has been already described as a process consisting of three markedly different stages. A statistically highly significant correlation existing between concentration losses of anthocyanins on the one hand and produced yeast biomass on the other was corroborated. As compared with unfiltered control, losses of anthocyanins and colour intensity of red wine were higher after the cross-flow filtration than in case of sheet filtration. It was demonstrated that sensory changes in colour intensity resulted from clarification of red and rosé wine by means of bentonite. The estimated rate constants of a decrease in concentration of monomeric anthocyanins during the ageing of wine agreed with measured values of the kinetic equation of the first-order reaction. In the course of storage of rosé wine samples in bottles it was identified pyranoanthocyanins. Temperature and duration of storage of rosé wines showed a more significant effect on the measured colour characteristics than the light exposure.
Keywords: grapes; grape varieties; vinification; wine ageing; red wines; rosé wines; anthocyanins; colour of wines

Ulrich, R., Janata, P., Mikita, T., Klimánek, M., Suchomel, J.: Practical applicatbility of satelite navigation systems for navigation and logistics of logging and hauling machines. Folia univ. agric. et silvic. Mendel. Brun., 2010, Vol. III, No. 4

GPS is not the only satellite navigation system but at present, it is certainly the most widely used system. GPS is able to ensure the coverage of the whole Earth's surface by navigation signals making possible to determine the position nearly anywhere on the Earth. Therefore, it is called a global navigation system enabling to determine a three-dimensional position, the speed of movement and to obtain an accurate time signal for all users.

To increase the effectiveness of work some harvesters and forwarders are additionally equipped with the GPS system. The accuracy of GPS systems used in these machines is particularly affected by the type of used receivers and specific properties of the forest environment. The whole project was divided in three interconnected parts. In the first part, effects of stand characteristics on the accuracy of GPS measurements were evaluated. After the first partial realization outputs, the second stage of the project followed where results of the first output became a basis for the configuration of reference GIS GPS receivers in logging and hauling machines. The contents of the second part of the project consisted in testing the GPS accuracy to optimize logging and hauling activities in forest stands. The last part uses all findings from previous parts to prepare methodology and introductory analysis to create navigation software for the movement of machines on the working area.

Advantages of the navigation system: Operators of logging and hauling machines are continuously informed on the machine position according to information from GPS if there is a sufficient signal at the locality at least from four satellites. The forwarder operator can plan passages along hauling lines on the basis of data converted from a harvester to prevent passages with half load or no-load or reverse running with a load. The forwarder need not follow at once the harvester to haul all logs in winter because even logs of assortments hidden under snow are well depicted on a display. Thus, no forgotten logs remain in the forest (dispersed incidental felling). The operator has an immediate view of the machine position in the stand and the size of already processed area. The navigation system ensures better orientation of operators of logging and hauling machines under complicated terrain conditions. It also prevents accidental felling outside the stand boundary and makes possible the forwarder operator to find all produced logs. There are possibilities to keep accurate records of wood assortments for particular JPRL (forest units), especially when more neighbouring parts of stands with indistinct boundary are processed. The direction and the spacing of hauling lines are observed without necessity to mark them. Piles of assortments are placed on truck landings for easier hauling. A technological card in digital form is printed out for the forest owner before the start of felling operations (the correspondence of data with PC on logging and hauling machines).

Keywords: navigation in a stand; digital stand map; GPS system; hardware and software in the PC of machines; stand preparation on a PC; data transfer between users

 
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ISSN 1803-2109 (Print)