The research on pre-diapause feeding of C. septempunctata L. adults was carried out from 1998 to 2002 in the Tiber Valley, in the Botanical Garden of Perugia University, and in the Sibillini Mountains National Park (Central Italy). The species reproduces in spring feeding mostly on aphids infesting Graminaceae. In the second half of June, newly emerged adults have various migratory behaviours. Some of them remain in the valley while some leave the cereals and fly to other crops, where they feed both on 15 aphid species (e.g., Aphis gossypii Glov. on melon, Aphis fabae Scop. on sugarbeet), and also on pollens of wild plants such as Carduus nutans L., and fungi spores. However, most of the adults migrate to mountain pastures to find different food sources. During this migration, strong south-western storms often force the ladybirds to shelter in urban habitats. When the sunny weather returns again, due to the mistral (north-western wind), the adults continue the flight in swarms to mountain areas. In 1999, on Mt. Vettore (2478 m) we witnessed a "shower" of ladybirds, some of which hid in the turf. When reaching high altitude locations still covered with snow (Lake Pilato, 1940 m, on Mt. Vettore), the adults, exhausted by the long flight, usually remain motionless on the snow. Due to the warming of the sun they sink to a depth of 5-6 cm, so that they remain trapped in the frozen snow during the night. At this site C. septempunctata was found together with Vibidia duodecimguttata (Poda) and Leptinotarsa decemlineata (Say). We investigated the gut content of adults from this location. After aggregation, the hungry adults disperse to flowering plants at lower elevations where they feed on 8 aphid species (e.g. broom aphid) and pollens of several plants (e.g., Laserpitium garganicum Tem., Centaurea rupestris L., Cachrys ferulacea L. The first mating was observed on broom. At "Pian Grande" location, adults were found in crop fields (lentil, mustard) and wild pastures (cornflower, gentian) mating and feeding on aphids, pollens, nectar and fungal spores. Haymaking forces ladybirds to move towards higher locations in search of food. Echinops ritro L., Eryngium amethystinum L., Carlina acaulis L., Cirsium eriophorum (L.), Galium verum L. and Euphorbia cyparissias L. were major food sources at 1800 m altitude. Gut content of C. septempunctata adults showed that pre-diapause diet consisted of aphids, pollen of Compositae and Umbelliferae, and spores of fungi (e.g., Alternaria spp., Cladosporium spp.). There was no statistical difference between the number of adults containing remains of aphids, fungal spores, and pollens. We found four significant correlations between the different food sources observed. In August some adults stopped feeding and in diapause condition sheltered under stones and among leaves or seed capsules of plants where they had fed. Others migrated to nearby woods and aggregated between juniper needles.
The Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is known to thrive principally in shrubby and arboreal habitats. This study focuses on the occurrence of this exotic species and its seasonal abundance in various field crops. The abundance of adults, larvae and pupae of H. axyridis was evaluated over a three-year period, from 2009 to 2011, in four important agronomical crops (wheat, corn, broad bean and potato) in Belgium. From May to September, 48 1-m² quadrats were visually inspected in each of the fields sampled on several farms every seven days. H. axyridis colonized and reproduced in all of the four crops studied, with the largest numbers recorded in corn and broad bean crops. Larvae and adults of H. axyridis were recorded mainly in corn and to a much less extent in wheat and potato crops. From 2009 to 2011, the mean weekly abundance of H. ayxridis remained constant except in corn crops, where the recorded densities of all the immature stages and adults were higher in 2011 than in 2009. The population dynamics of aphids and H. axyridis are well described by a symmetric logistic function (S-shape) of cumulative population size. H. axyridis was not always recorded where aphids were abundant, e.g. aphids were abundant on wheat where no H. axyridis were recorded. H. axyridis start reproducing after the peak in aphid population, suggesting that H. axyridis is able to complete its development by feeding on alternative prey such as larvae and pupae of the same and other species of ladybird and other aphidophagous species. H. axyridis is often considered to be bivoltine but it only completes one generation per year in field crops. The second generation generally develops late in the season in other habitats., Axel Vandereycken ... [et al.]., and Obsahuje seznam literatury
The review is done to summarise the history of the discoveries of the many anatomical, agronomical, and physiological aspects of C4 photosynthesis (where the first chemical products of CO2 fixation in illuminated leaves are four-carbon dicarboxylic acids) and to document correctly the scientists at the University of Arizona and the University of California, Davis, who made these early discoveries. The findings were milestones in plant science that occurred shortly after the biochemical pathway of C3 photosynthesis in green algae (where the first chemical product is a three-carbon compound) was elucidated at the University of California, Berkeley, and earned a Nobel Prize in chemistry. These remarkable achievements were the result of ground-breaking pioneering research efforts carried out by many agronomists, plant physiologists and biochemists in several laboratories, particularly in the USA. Numerous reviews and books written in the past four decades on the history of C4 photosynthesis have focused on the biochemical aspects and give an unbalanced history of the multidisciplinary/multinstitutional nature of the achievements made by agronomists, who published much of their work in Crop Science. Most notable among the characteristics of the C4 species that differentiated them from the C3 ones are: (I) high optimum temperature and high irradiance saturation for maximum leaf photosynthetic rates; (II) apparent lack of CO2 release in a rapid stream of CO2-free air in illuminated leaves in varying temperatures and high irradiances; (III) a very low CO2 compensation point; (IV) lower mesophyll resistances to CO2 diffusion coupled with higher stomatal resistances, and, hence, higher instantaneous leaf water use efficiency; (V) the existence of the so-called "Kranz leaf anatomy" and the higher internal exposed mesophyll surface area per cell volume; and (VI) the ability to recycle respiratory CO2 by illuminated leaves.
The aim of this study was to clarify the diet of Ceratomegilla notata (Laicharting), a common species in different mountain habitats of the Palearctic region. In Italy it is found only in alpine ecosystems between 800-1700 m. In these areas, up to 1200 m, various crops (e.g., maize, potatoes) are present. The high meadows are cut for hay. From 2002 to 2003 investigations on the foraging behaviour of this ladybird were carried out in mountain habitats (six near Villabassa, in Bolzano province, and six near Soraga, in Trento province) and in the "Paradisia" Botanic Garden (Gran Paradiso National Park). C. notata adults and larvae were found on the flowering plants, especially those infested by aphids. The study of their diet was done taking random D-Vac samples of 20 adults and 20 larvae/habitat every 15 days, between July and September. The influence of the haymaking on C. notata populations was also evaluated.
In agricultural fields the ladybirds prey on Rhopalosiphum maidis (Fitch), R. padi (L.) on maize and on Acyrthosiphon pisum (Harris) and Therioaphis luteola (Born.) on Trifolium pratense L. In the natural pastures, adults and larvae feed on Cavariella theobaldi G. & B. found on Heracleum sphondylium (Umbelliferae), Sitobion avenae L. on Avena sativa L., Megoura viciae (B.) and A. pisum on Vicia cracca L., Uroleucon jaceae (L.) on Cirsium arvense Scop., U. cichorii (Koch) on Hypochaeris radicata L. and Macrosiphum weberi Born. on Scabiosa sp. A study of the gut contents revealed the presence of aphids, Umbelliferae pollens and spores of fungi (e.g., Alternaria spp., Helminthosporium spp., Puccinia spp.). Statistically significant associations between different food sources were more frequent for adults than for larvae in both 2002 and 2003. Thrips are an important prey of this ladybird in the absence of aphids. C. notata is an important aphidophagous species in Alpine habitats.
Presented are results of simulations of root water uptake applying a macroscopic model of water transport in Soil - Plant - Atmosphere - Continuum. As a simulation tool is used the software package GLOBAL, based on the solution of the one-dimensional Richards equation. The main objective is to examine the contribution of root extraction functions (sink terms) based on different root morphological parameters to the changes in the soil water content profiles during the vegetation period of three crops. The root extraction functions are estimated using dry mass, length and surface area density distributions of all (total) and the fine roots (< 0.5 mm) of spring barley, winter rye and maize. It was observed that the ''root mass'' extraction curves slightly deviate from the ''length'' and ''surface area'' ones, especially in the topsoil and for the crops with a longer vegetation period. Nevertheless, the resulted differences in the soil water content distributions were small. The role of ''fine roots'' distribution was also examined. Calculating the water storage, it was found that the deviations were within the error of direct measurements. The sensitivity of the models based on the Richard´s equation to the different root extraction functions was found to be low, which reflected in small differences in soil water content distributions. Hence, any of the studied root morphological parameters can be successfully applied for simulations of root uptake at macro scale. and Práca obsahuje výsledky simulácie odberu vody koreňmi rastlín makroskopickým modelom pohybu vody v systéme pôda - rastlina - atmosféra, ak boli funkcie odberu vody koreňovým systémom určené z rozdelení rôznych charakteristík koreňového systému. Použili sme simulačný model GLOBAL, založený na riešení jednorozmerného tvaru rovnice Richardsa. Cieľom práce bolo určiť funkcie odberu vody koreňovým systémom rastlín, s využitím rozdelenia rôznych charakteristík koreňového systému tej istej rastliny a ich vplyv na vlhkostné profily v pôde počas ontogenézy rastlín. Simulácia bola vykonaná pre tri porasty - jarný jačmeň, ozimnú raž a kukuricu. Funkcie odberu vody boli vypočítané z údajov o rozdelení hmotnosti suchých koreňov, ich mernej dĺžky a merného povrchu pre všetky korene a pre ''jemné'' korene (< 0,5 mm v priemere). Ukázalo sa, že funkcie odberu založené na rozdelení hmotnosti koreňov sa nevýrazne odlišovali od tých, ktoré boli vypočítané s použitím ''dĺžky'' a ''povrchu'' koreňov v orničnej vrstve pôdy a pre porasty s dlhším vegeračným obdobím. Aj rozdiely medzi funkciami odberu s využitím rozdelenia rôznych vlastností ''jemných'' a všetkých koreňov boli v medziach presnosti merania. Z toho vyplýva, že ľubovoľný z použitých rozdelení parametrov koreňov (hmotnosť, dĺžka, povrch) môže byť použitý na výpočet odberových funkcií pre simuláciu pohybu vody v systéme PRAT a následnú simuláciu makroskopickými modelmi, založenými na riešení rovnice Richardsa.