Instability of Alien Chromosome Introgressions in Wheat Associated with Improper Positioning in the Nucleus

Alien introgressions introduce beneficial alleles into existing crops and hence, are widely used in plant breeding. Generally, introgressed alien chromosomes show reduced meiotic pairing relative to the host genome, and may be eliminated over generations. Reduced pairing appears to result from a failure of some telomeres of alien chromosomes to incorporate into the leptotene bouquet at the onset of meiosis, thereby preventing chiasmate pairing. In this study, we analysed somatic nuclei of rye introgressions in wheat using 3D-FISH and found that while introgressed rye chromosomes or chromosome arms occupied discrete positions in the Rabl’s orientation similar to chromosomes of the wheat host, their telomeres frequently occupied positions away from the nuclear periphery. The frequencies of such abnormal telomere positioning were similar to the frequencies of out-of-bouquet telomere positioning at leptotene, and of pairing failure at metaphase I. This study indicates that improper positioning of alien chromosomes that leads to reduced pairing is not a strictly meiotic event but rather a consequence of a more systemic problem. Improper positioning in the nuclei probably impacts the ability of introgressed chromosomes to migrate into the telomere bouquet at the onset of meiosis, preventing synapsis and chiasma establishment, and leading to their gradual elimination over generations

How alpine heathlands response to the snow cover change on the ski slope? Long-lasting ski slope impact case study from the Hrubý Jeseník Mts (Central Europe)

The distribution and duration of snow cover are important variables that affect ecosystem processes in the alpine zone. The establishment of ski resorts dramatically change their surrounding environment and ski slopes represent significant anthropogenic impact in the mountains. We assessed the changes in environmental factors, phenology, growth, and reproductive performance of bilberry (Vaccinium myrtillus), a dominant species of alpine heathlands, caused by a “nature-friendly” managed ski slope (i.e., without artificial snow and machine grading) at permanent plots established on the ski slope under operations (inside the ski slope) and on an unaffected control area (outside the ski slope). A lower mean temperature and a shorter time of great temperature fluctuation during snow melting, a longer time span of snow cover, and a higher snow water equivalent were observed inside the ski slope compared to outside it. Due to changed environmental conditions, the beginning of growth was postponed, and a delay in phenological development was observed in the bilberry at the ski slope. However, bilberry ripened both inside and outside the ski slope in a similar period and showed similar cover and even higher flower and fruit densities inside the ski slope compared with natural surroundings. The persistence of bilberry was not deteriorated and its performance was even better inside the ski slope. On the ski slope, managed snow cover can reduce the potential vegetation shifts due to expected impact of the climate warming. That should be taken into account in conservation and management planning

Biology and Yield of Rocket (<i>Eruca sativa</i> Mill.) under Field Conditions of the Czech Republic (Central Europe)

Five rocket (Eruca sativa (L.) Mill.) varieties and accessions were cultivated under field conditions in the Czech Republic (Central Europe) and subsequently studied for variation in morphology and yield. Two cultivation techniques (treatments) were tested during the growing seasons in 2010 and 2011: directly sown seeds in the field and plantlets cultivated in a glasshouse and later transplanted to the field. There were analysed four morphological parameters of the leaf rosette (leaf shape in outline, leaf margin, leaf apex and leaf colour), marketable yield, nonmarketable parts, and rosette radius. Plants from plantlets transplanted to the field in spring terms (April) yielded a substantially higher marketable yield and had a higher rosette radius in contrast to plants from directly sown seeds. Conversely, for the summer terms (late August, September) the direct sowing technique produced higher marketable yield in comparison with plantlets treatment. Plants cultivated from directly sowed seeds reached a marketable yield on average from 15 to 60 g per plant while transplanted plants produced on average from 10 to 49 g per plant. It is evident that cultivation of rocket under field conditions of the Czech Republic is possible and provides, when using the appropriate sowing term, more or less stable yields of marketable parts. Details on variation in yield parameters of individual varieties and accessions are presented

Mosses of art objects in the public space of selected central Moravian cities

V této práci jsme se zaměřili na průzkum bryoflóry uměleckých objektů ve veřejném prostoru tří středomoravských měst (Olomouc, Přerov a Prostějov). Studované objekty jsou spojené převážně s obdobím od konce druhé světové války do roku 1989, tedy s dobou, která nejvíce obohatila intravilány měst tehdejšího Československa uměleckou výzdobou. Na umělecká díla je nahlíženo přírodovědným pohledem a jsou chápána jako sekundární stanoviště kolonizovaná mechy. Přítomnost mechů byla prokázána na 30 % objektů. Celkově jsme nalezli 32 druhy mechů. Mezi nejčastější druhy patřily Tortula muralis, Orthotrichum diaphanum a Bryum argenteum. Z vzácnějších druhů byl zaznamenán výskyt druhů Orthotrichum striatum, Schistidium confusum a Syntrichia latifolia. Ve studii je diskutován kolonizační potenciál mechů a jejich role v kolonizačním procesu, druhová skladba a podmínky prostředí, jež měly signifikantní vliv na druhové složení.Mosses are an integral but neglected part of vegetation in the urban environment. However, studies of the bryoflora on art objects in the public space are scarce. We therefore focused on the composition and environmental determinants of the bryoflora of art objects in the public space of three central Moravian cities (Olomouc, Přerov and Prostějov). The art objects are mainly connected with the period from the end of the Second World War to 1989, that is, with the time that most enriched the cities of former Czechoslovakia with art in the public space. The works of art are perceived from a natural scientific point of view, and they are seen as secondary habitats colonized by mosses. We proved the presence of mosses on 30% of the objects. The most common species were Tortula muralis, Orthotrichum diaphanum and Bryum argenteum. Among rarer species, the occurrence of Orthotrichum striatum, Schistidium confusum and Syntrichia latifolia has been reported. We discussed the colonization potential of mosses and their role in the colonization process, together with the environmental conditions that had a significant effect on species composition. Light conditions were identified as the only significant environmental´factor affecting the bryoflora on the art objects examined