Respiration und Freigabe von Aethylen in Beziehung zu den verschiedenen Entwicklungsphasen der Knollenbildung bei Kartoffeln

Zusammenfassung Die Geschwindigkeit der Respiration, die Freisetzung an Aethylen sowie die Gewichtszunahme an Knollen wurde w?hrend der Vegetation in der Zeit von Juni bis Oktober bei drei Kartoffelsorten (Resy, Karin, Kamyk) unter gleichen Anbaubedingungen geprüft. Die Anfangsphase der Knollenbildung wird durch eine starke Erh?hung der Respirationsaktivit?t und Freisetzung von Aethylen charakterisiert. In der Phase der Hemmung der Wachstumsaktivit?t der Pflanze vermindert sich dann die St?rke der Respiration sowie die Menge an Aethylen, das Knollengewicht steigt weiter an. Die Reihenfolge des Maximums der Respiration und Freisetzung an Aethylen ist nicht gleich, d.h. das Maximum der Respiration wird bei der Sorte Kamyk erreicht. Demgegenüber liegt das Maximum der Freisetzung von Aethylen bei der Sorte Karin. Die H?he der Respiration und die Freisetzung von Aethylen in Beziehung zum Knollengewicht scheint sortenspezifisch zu sein.     

Eradication of potato viruses A and S by thermotherapy and sprout tip culture

Summary Potato viruses A and S have been eradicated from varietiesJara andRajka by applying thermotherapy combined with nutrient culture of excised sprout tips.     

Long-term effect of straw and farmyard manure on soil organic matter in field experiment in the Czech Republic

The effect of long-term (45 years) mineral and organic fertilization on soil organic matter (SOM) quantity (organic C and N content) and quality (hot-water-soluble C content, microbial biomass C content, hydrophobic organic components of SOM, soil enzyme activities) was determined in a field experiment established in Trutnov (North Bohemia, sandy loam, Eutric Cambisol). Six treatments were chosen for investigation: unfertilized control, mineral fertilization (NPK), straw N, farmyard manure (FYM) and straw and FYM completed with mineral NPK. Soil samples were taken from the arable layer (0–20 cm) in spring over the period of 2004–2010. The positive effect of FYM on the total organic C and N content, hot-water-soluble C content and hydrophobic organic components of SOM was more than 50% higher than that of straw and mineral N fertilization. Application of straw N increased microbial biomass C content in soil and generated invertase activity above the level of FYM. Hot-water-soluble C content, hydrophobic organic components of SOM and urease activity were positively correlated with total organic C and N content (R = 0.58–0.98; p < 0.05). Addition of mineral NPK to both the straw and FYM emphasized the effect of organic fertilization in most of monitored characteristics.     

Assessment of phenotypic variation of Malus orientalis in the North Caucasus region

Malus orientalis Uglitzk. is the predominant Malus species of the Caucasian forests distributed in the north of Anatolia, Armenia, Russia as well as in Iran. It is considered as one of the probable minor ancestors of domestic apples. Although M. orientalis has a lower diversity of fruit quality, other valuable traits such as later blooming, adaptation to a wider array of habitats, and capacity for longer storage of the apples should be taken into account for improving the genetic makeup of the domestic apple. A joint expedition of scientists of the Julius Kühn-Institute from Germany and the Nikolaj I. Vavilov Research Institute of Plant Industry from Russia was performed into the North Caucasus region during August/September 2011. Altogether 101 M. orientalis accessions were collected from eight sites at the North Caucasus. Twenty-six traits such as size, color, shape, flavor and firmness of fruit and tree habit were used for phenotypic evaluation of the accessions. A high phenotypic diversity within the collected material of M. orientalis was indicated. Accessions characterized by suitable fruit traits like bigger size, larger cover color, less bitterness and better firmness as well as more sweetness and better flavor were found. However, small-sized flavorless fruits were also detected. Tree habit varied widely from upright to weeping. Subsequently, a comprehensive phenotypic and genetic evaluation of M. orientalis increases the knowledge of diversity, may provide new resources of agronomically important traits for breeding purposes, and gives support to determine accessions for a core collection.     

Conflicting results of serological,PCR and microscopic methods clarify the various risk levels of canine babesiosis in Slovakia: A complex approach to Babesia canis diagnostics

We have performed a survey of Babesia canis prevalence within group of dogs living in Southern and Western Slovakia. Blood samples and sera from 217 dogs, including individuals suspected of having babesiosis, were examined by nested PCR-RFLP, light microscopy and indirect fluorescence antibody test (IFAT). The detection of B. canis DNA revealed the highest number of infected dogs in the region of Nové Zámky, with 23 B. canis-positive blood samples (35.4%, n = 65), followed by an area close to Komárno (both areas of Southern Slovakia), where 1 dog out of 52 collected (1.9%) had detectible B. canis DNA in the blood stream. The serological method revealed an opposing pattern, with only 3 dogs (4.8%, n = 63) sampled at Nové Zámky presenting IgG antibodies against B. canis, while in Komárno region such antibodies were detected in 15 dogs (28.8%, n = 52). This discrepancy may be because the majority of samples from Nové Zámky were dogs suspected of an acute phase of canine babesiosis, whereas dogs at Komárno were sampled during a vaccination campaign, and thus were without any clinical signs of the disease. The latter group contains evidently recovered carriers of IgG against B. canis. Hence, the combination of PCR-based and serological methods enabled us to discover both recently infected as well as recovered dogs, thus obtaining a more realistic view on the epidemiological situation. Remarkably, we did not find any positive samples in the vicinity of Stupava (district Malacky, Western Slovakia), either by PCR-RFLP, microscopy or IFAT (n = 100). Considering the numerous falsely diagnosed cases of canine babesiosis, we suggest that light microscopy as the simplest and most accessible diagnostic test. Southern Slovakia was confirmed as an area of high risk of canine babesiosis, whereas conclusions about B. canis spreading over Western Slovakia should be considered with wariness.     

A comparative study of the Barley yellow dwarf virus species PAV and PAS: distribution,accumulation and host resistance

This study investigated the distribution and characteristics of the Barley yellow dwarf virus (BYDV) species BYDV‐PAS, which was recently separated from BYDV‐PAV, the most commonly studied BYDV species. Throughout 3 years of experimental monitoring of BYDV incidence, PAS was the most frequently occurring species infecting cereals and grasses in the Czech Republic. Furthermore, Rhopalosiphum maidis and Metopolophium dirhodum were recorded as BYDV‐PAS vectors, even though M. dirhodum does not usually transmit BYDV‐PAV. In field experiments with barley and wheat, where virus accumulation, symptoms and effect on the yield were tested, BYDV‐PAV was more severe than PAS. Infection with the BYDV‐PAV isolate resulted in greater expression of symptoms and also in a greater reduction in plant height and grain weight per spike than BYDV‐PAS. In a sensitive cultivar of barley (Graciosa), the amount of viral RNA of BYDV‐PAV was also significantly higher than that of BYDV‐PAS. In a tolerant line (Wbon‐123), however, no such differences were found. In conclusion, although BYDV‐PAS seems to be dominant in the Czech Republic, BYDV‐PAV has the potential to cause more significant crop losses in barley and wheat.     

Accumulation of phenolic compounds in apple in response to infection by the scab pathogen,Venturia inaequalis

The research dealt with phenolics in healthy versus scab infected apple leaves and fruits. The leaf samples were picked in the period from May to September and the fruit samples at technological maturity. Infection with the Venturia inaequalis fungus enhanced the metabolism of phenolics at the infected sites, especially in the boundary tissue. Tissue infected with Venturia inaequalis showed in comparison to the healthy tissue up to 7.6 times more hydroxycinnamic acids, up to 2.6 times more flavan-3-ols and up to 2.9 times higher values of flavanols. The content level of total phenolics in the infected tissue was 1.3–2.4 times higher than in the healthy leaves and fruit.     

Comparison of two methods for field grow of puncture vine (Tribulus terrestris L.) in Slovakia

One of the most claimed aphrodisiac plant is puncture vine (Tribulus terrestris L.) known as ‘plant Viagra’. This herb, growing especially in South and East Europe, is used for pharmaceutical purposes, due to its content of furostanol saponins which have stimulant effects on natural testosterone levels. Puncture vine grows as a weed on sandy soils areas. A study aimed to the introduction of puncture vine into large cultivation scale was carried out. Two different methods of cultivation were compared and production of biomass and evaluation of the content of furostanol saponins were done. Transplantation of seedlings raised in the greenhouse into the open field was more effective for the production of high amount of biomass and active components than using plants that are directly sown. The transplantation of seedlings into open field is suitable for the puncture vine cultivation as it increases biomass production.