Wstepne badania nad wartoscia biologiczna pylku, stosunkami zapylania oraz zawiazywaniem owocow u wybranych odmian wisni w warunkach centralnej Polski

Preliminary experiments were carried out in spring 2006. The percentage of fruit set of ‘Schattenmorelle IR-2’, ‘Koral’, ‘Debreceni Bötermö’, ‘Újfefértói Fürtos’ and ‘Karneol’ was higher after open pollination compared with self-pollination. The cultivar Vowi had an inconsiderably higher percentage of fruit set after self-pollination compared with open pollination. The percentage of fruit set in ‘Debreceni Bötermö’ and ‘Újfehértói Fürtos’ was about 25 % higher after pollination by ‘Schattenmorelle IR-2’ and ‘Koral’ compared with the percentage of fruit set after cross – pollination of both cultivars with each other. In general, they did not appear to be good pollinators with each other. The highest quality of pollen was observed for the following cultivars: ‘Schattenmorelle IR-2’, ‘Koral’ and Vowi and the lowest result was obtained in ‘Újfehértói Fürtos’. The highest yield was given by the following cultivars: Vowi, Schattenmorelle IR-2 and Koral.W ciągu dwuletnich badań nad żywotnością pyłku i zdolnością jego kiełkowania u 6 odmian wiśni zaobserwowano różnice międzyodmianowe badanych cech biologicznych pyłku. Najwyższy procent żywotnego i kiełkującego pyłku stwierdzono u odmian: Łutówka IR-2, Koral i Vowi. Odmiana Újfehértói Fürtös (Groniasta z Újfehértói) posiadała najniższy procent żywotnego i kiełkującego pyłku. Wstępne badania nad stosunkami zapylania, przeprowadzone wiosną 2006 roku, również wykazują różnice pomiędzy poszczególnymi odmianami. Dwie odmiany węgierskie: Debreceni Bötermö i Újfehértói Fürtös, które w rodzimych warunkach zachowują się jak odmiany samopłodne, w warunkach centralnej Polski do uzyskania zadowalającego plonu potrzebują obecności zapylaczy. Dobrymi zapylaczami dla tych odmian okazały się: ‘Koral’ i ‘Łutówka IR-2’. Drzewa odmian: Koral, Łutówka IR-2 oraz Vowi wydały zadowalający plon po zapyleniu kwiatów własnym pyłkiem. Jednak u drzew wszystkich odmian z wyjątkiem ‘Vowi’, procent zawiązanych owoców był wyższy w przypadku wolnego zapylenia niż w przypadku zapylenia własnym pyłkiem. Najwyższy plon w 2006 roku uzyskano z drzew odmian Vowi, Łutówka IR-2 i Koral. W 2007 roku kwiaty i zawiązki owoców wiśni zostały uszkodzone przez przymrozki wiosenne. Z tego powodu oszacowanie procentu zawiązanych owoców w poszczególnych kombinacjach zapyleń jak również oszacowanie plonu było niemożliwe. Najbardziej ucierpiały odmiany: Debreceni Bötermö i Újfehértói Fürtös, jak również odmiany niemieckie. Najmniej wrażliwa na przymrozki okazała się odmiana Łutówka IR-2

The effect of environmental parameters and cyanobacterial blooms on phytoplankton dynamics of a Portuguese temperate Lake

Abstract The increasing occurrence of cyanobacterial blooms in freshwaters is of great concern due to the ability of many cyanobacteria to produce cyanotoxins. In the present work, the eutrophied Vela Lake (Central Portugal), used for recreational purposes and as a water source for agriculture, was monitored every fortnight between 2000 and 2001. Phytoplankton diversity and densities were measured and correlated to environmental parameters. A seasonal phytoplanktonic succession was observed and it was mainly correlated with conductivity, temperature, total suspended solids and nutrients availability (particularly phosphorus). Diatoms were dominant during winter months (inferior temperatures and higher nutrients availability) followed by green algae in early spring and then cyanobacteria from late spring until early autumn (less nutrient availability and higher temperatures). A massive cyanobacterial bloom of Aphanizomenon flos-aquae occurred early in May 2001 and was preceded by the lowest nitrogen levels measured in the water during all the study period. At the time of this bloom senescence, dissolved oxygen was severely depleted and a massive death of ichthyofauna was recorded. A Microcystis aeruginosa bloom was also detected in July 2001 and it occurred following a rapid decrease in abundance of green algae and diatoms. By considering not only the environmental parameters but also the occurrence of cyanobacterial blooms as explanatory variables in a canonical correspondence analysis, the variance explained for the phytoplanktonic assemblage during the study period was increased in about 7% achieving a total of 61.0%, indicating a correlation that may be due to the known competitive advantage and/or allelopathy of the bloom-forming cyanobacteria towards microalgae

Trait‐based approach using in situ copepod images reveals contrasting ecological patterns across an Arctic ice melt zone

International audienceImaging techniques are increasingly used in ecology studies, producing vast quantities of data. Inferring functional traits from individual images can provide original insights on ecosystem processes. Morphological traits are, as other functional traits, individual characteristics influencing an organism's fitness. We measured them from in situ image data to study an Arctic zooplankton community during sea ice break‐up. Morphological descriptors (e.g., area, lightness, complexity) were automatically measured on ∼ 28,000 individual copepod images from a high‐resolution underwater camera deployed at more than 150 sampling sites across the ice‐edge. A statistically‐defined morphological space allowed synthesizing morphological information into interpretable and continuous traits (size, opacity, and appendages visibility). This novel approach provides theoretical and methodological advantages because it gives access to both inter‐ and intra‐specific variability by automatically analyzing a large dataset of individual images. The spatial distribution of morphological traits revealed that large copepods are associated with ice‐covered waters, while open waters host smaller individuals. In those ice‐free waters, copepods also seem to feed more actively, as suggested by the increased visibility of their appendages. These traits distributions are likely explained by bottom‐up control: high phytoplankton concentrations in the well‐lit open waters encourages individuals to actively feed and stimulates the development of small copepod stages. Furthermore, copepods located at the ice edge were opaquer, presumably because of full guts or an increase in red pigmentation. Our morphological trait‐based approach revealed ecological patterns that would have been inaccessible otherwise, including color and posture variations of copepods associated with ice‐edge environments in Arctic ecosystems