Environmental contaminants like polycyclic aromatic hydrocarbons can influence many biochemical and physiological processes in plants. The effect of 0.1, 1 and 5 mg l -1 of fluoranthene (FLT) in combination with indole-3-acetic acid (IAA, 0.1 mg l -1 ) or a combination of IAA and N 6 -benzyladenine (BA, both 0.1 mg l -1 ) on the growth and production of ethylene, ethane and CO 2 in Pisum sativum L. cultivated for 21 days in vitro was investigated. In 21 days old plants also net photosynthesis rate, content of FLT and cytokinins were evaluated. FLT 5 mg l -1 significantly inhibited the growth of pea after 21 days in both IAA and IAA ? BA treatments, increased production of ethylene (by 11% in IAA and 14% in IAA ? BA treatments, respectively) and ethane (by 28 and 18%) and decreased production of CO 2 (by 23 and 29%). The net photosynthesis rate decreased in response to FLT concentration by up to 51% under saturating irradiation (600-1,200 lmol m -2 s -1 ), as found in IAA ? BA ? FLT 5 mg l -1 treatment. The content of FLT in pea plant shoots well correlated with increasing FLT treatment in both IAA and IAA ? BA medium. The content of cytokinins in pea shoots changed in response to FLT treatment. FLT 5 mg l -1 caused a rise in level of trans-zeatin (by 16% in IAA and 9% in IAA ? BA treatments, respectively), dihydrozeatin riboside (by 27 and 50%), benzyladenine (by 3 and 80%), benzyladenine riboside (by 44 and 17%) and meta-topolin riboside (by 139 and 214%), no change in isopentenyladenine level and a decrease in metatopolin level (by 33% in IAA and 36% in IAA ? BA treatments, respectively). Cultivation of plants in vitro allowed not only to assess their growth, photosynthetic activity and the level of cytokinins, but also to extend the knowledge about the effect of PAHs on production of gaseous stress indicators like ethylene, ethane and CO 2 . Recorded changes in all studied parameters show, that persistent organic pollutants like PAHs can negatively influence plant growth and development.

This study confirmed the considerable effect of polycyclic aromatic hydrocarbon fluoranthene (FLT; 0.01, 0.1, 1, 4 and 7 mg/l) exposure on the germination of seeds, growth and root morphology of seedlings in Zea mays and Pisum sativum. Seed germination was significantly inhibited at FLT≥0.01 mg/l in maize and at ≥1 mg/l in pea. The amount of released ethylene after 3 days of germination was significantly increased in both species at FLT≥0.1 mg/l. After 7 days of seedling cultivation a significant decrease in the dry weight of roots and shoots occurred in maize at FLT≥0.1 mg/l while in pea similar effect was observed at ≥1 mg/l. The total length of primary and lateral roots was significantly reduced by FLT≥1 mg/l in maize and by 4 and 7 mg/l in pea. The length of the non-branched part of the primary root was significantly reduced by FLT≥0.1 mg/l in maize and ≥0.01 mg/l in pea. In both species the number of lateral roots was significantly increased at FLT≤1 mg/l and inhibited at concentrations of 4 and 7 mg/l. Fluoranthene content in roots and shoots of both species positively correlated with the FLT treatment.

The paper deals with problems associated with preparation and collection of samples when estimating the production of ethylene and content of ACC (1-aminocyclopropane-1-carboxylic acid) in plants by means of gas chromatography. A proper method of sampling can significantly influence not only the reliability of obtained data but also their interpretation. Attention was paid to cultivation of plant material, sampling vessels, conditions of ethylene production, sampling procedure, and storage of gaseous samples. The estimation of ACC as a precursor of ethylene is more laborious but it supplements the information about the endogenous level of ethylene in a given part of the plant organism. The authors describe the sampling procedure, methods of sample preservation, extraction and purification, and also the method of oxidation of ACC to ethylene. In the final part of this study the authors evaluate the time consumption and difficulty of individual methods and describe their advantages and disadvantages as compared with other, alternative methods.

This study compares effects of 2,3,5-triiodobenzoic acid (TIBA) and flavonoid quercetine (Q). In spite of the fact that both these compounds are inhibitors of the polar transport of auxin, a number of experiments demonstrated that their properties are different. If the flax seedlings were decapitated and one cotyledon was removed, the axillary bud of the remaining cotyledon grew up more intensively while TIBA (0.5% applied in the form of a lanolin paste on the remaining cotyledon) induced a correlative reversal so that axillars of removed cotyledons grew up more intensively. However, when Q (0.5%) was applied on the remaining cotyledon in the form of a lanolin paste, this inhibition was not significant. In the lamina-deprived petioles of apple trees TIBA accelerated abscission while Q caused an inhibiting effect similar to that of auxin. TIBA applied on epicotyls of pea seedlings inhibited their growth by 35% while Q only by 15%. As far as the release of ethylene by pea seedlings is concerned, both compounds showed promoting effects similar to the effect of auxin.

1 Výzkumný ústav pivovarský a sladařský, a.s., Sladařský ústav Brno, Mostecká 7, 614 00 Brno / Research Institute of Brewing and Malting, PLC, Malting Institute Brno, Mostecká 7, 614 (2007)(2008)(2009), byly prováděny ve skleněných lahvích (3 800 ml) uzavřených pryžo-vou membránou. V těchto pokusech byl zkoušen vliv různé koncentrace ethylenu na kvalitativní ukazatele sladu. Vzhledem k malému objemu použitých nádob (2.000 ks obilek), však docházelo k rychlým změnám ve složení vzduchu, především k prudkému poklesu koncentrace kyslíku a nárůstu koncentrace CO 2 . U obilek pak probíhalo anaerobní dýchání s nepříznivým vlivem na kvalitu vyrobeného sladu. Úprava složení mezizrnného plynu byla dosahována použitím vhodných sorbentů [1].Naším cílem bylo navázat na předchozí výzkum a eliminovat výše uvedené nevýhody. Proto jsme se rozhodli provést experiment v mikrosladovně. Produkce ethylenu byla zajištěna jednoduchým, ale účin-ným způsobem. Využili jsme přirozené schopnosti plodů jablek produkovat ethylen. Plody byly přidány do podlísčí, a tak vytvořily požadovanou koncentraci ethylenu (200 až 300 nl.l -1 ) v ovzduší skříně mikrosladovny.  2 LITERÁRNÍ PŘEHLEDDormance je založena geneticky [2] a pokusy konané při posklizňové úpravě zrna působením vyšších či nižších teplot dormanci obilek výrazně neovlivnily [3, 4, 5]. Přesto bylo v posledních letech při sledování problematiky interakce dormance a zvýšení kvality výroby sladu ověřeno, získáno a upřesněno několik informací.V průběhu dormance, která ovlivňuje kvalitu sladu, obsah abscisové kyseliny a produkce ethylenu klesá [6]. Při procesu klíčení obilky uvolňují do prostředí oxid uhličitý za současné spotřeby kyslíku, a různé množství ethylenu a ethanu podle stupně dormance či stresových ovlivnění [1]. Tyto plyny v mezizrnném vzduchu zpětně působí na klí-čení obilek -na růst kořenů a koleoptile -střelky. Oxid uhličitý nepřímo [2007][2008][2009] were conducted in glass bottles (3 800 ml) closed with a rubber membrane. The effect of different ethylene concentrations on malt quality parameters was studied. Considering a small volume of the containers used (2,000 pcs of caryopses), air composition quickly changed, first of all sharp decrease in oxygen concentration and increase in CO 2 concentration. Respiration of caryopses was anaerobic with an unfavorable impact on the quality of produced malt. The inter-grain gas composition was adjusted with appropriate sorbents [1].The aim of this study was to continue in previous research and eliminate disadvantages stated above. Therefore we decided to carry out the experiment in a micromalting house. Ethylene production was ensured by a simple but effective manner. We used the natural ability of apples to produce ethylene. Added fruits formed the required concentration of ethylene (200 to 300 nl.l -1 ) in the air of maicromalting box.  2 SURVEY OF LITERATUREDormancy is of genetic nature [2] and it was not markedly influenced by higher of lower temperatures used in the course of experiments with post-harvest treatment of kernel...