Reduced Risk of Oat Grain Contamination with Fusarium langsethiae and HT-2 and T-2 Toxins with Increasing Tillage Intensity.

Frequent occurrences of high levels of Fusarium mycotoxins have been recorded in Norwegian oat grain. To elucidate the influence of tillage operations on the development of Fusarium and mycotoxins in oat grain, we conducted tillage trials with continuous oats at two locations in southeast Norway. We have previously presented the content of Fusarium DNA detected in straw residues and air samples from these fields. Grain harvested from ploughed plots had lower levels of Fusarium langsethiae DNA and HT-2 and T-2 toxins (HT2 + T2) compared to grain from harrowed plots. Our results indicate that the risk of F. langsethiae and HT2 + T2 contamination of oats is reduced with increasing tillage intensity. No distinct influence of tillage on the DNA concentration of Fusarium graminearum and Fusarium avenaceum in the harvested grain was observed. In contrast to F. graminearum and F. avenaceum, only limited contents of F. langsethiae DNA were observed in straw residues and air samples. Still, considerable concentrations of F. langsethiae DNA and HT2 + T2 were recorded in oat grain harvested from these fields. We speculate that the life cycle of F. langsethiae differs from those of F. graminearum and F. avenaceum with regard to survival, inoculum production and dispersal.

Inoculum Potential of Fusarium spp. Relates to Tillage and Straw Management in Norwegian Fields of Spring Oats.

The increased occurrence of Fusarium-mycotoxins in Norwegian cereals over the last decade, is thought to be caused by increased inoculum resulting from more cereal residues at the soil surface as a result of reduced tillage practices. In addition, weather conditions have increasingly promoted inoculum development and infection by Fusarium species. The objective of this work was to elucidate the influence of different tillage regimes (autumn plowing; autumn harrowing; spring plowing; spring harrowing) on the inoculum potential (IP) and dispersal of Fusarium spp. in spring oats. Tillage trials were conducted at two different locations in southeast Norway from 2010 to 2012. Oat residues from the previous year's crop were collected within a week after sowing for evaluation. IP was calculated as the percentage of residues infested with Fusarium spp. multiplied by the proportion of the soil surface covered with residues. Fusarium avenaceum and F. graminearum were the most common Fusarium species recovered from oat residues. The IP of Fusarium spp. was significantly lower in plowed plots compared to those that were harrowed. Plowing in either the autumn or spring resulted in a low IP. Harrowing in autumn was more effective in reducing IP than the spring harrowing, and IP levels for the spring harrowed treatments were generally higher than all other tillage treatments examined. Surprisingly low levels of F. langsethiae were detected in the residues, although this species is a common pathogen of oat in Norway. The percentage of the residues infested with F. avenaceum, F. graminearum, F. culmorum, and F. langsethiae generally related to the quantity of DNA of the respective Fusarium species determined using quantitative PCR (qPCR). Fusarium dispersal, quantified by qPCR analysis of spore trap samples collected at and after heading, generally corresponded to the IP. Fusarium dispersal was also observed to increase after rainy periods. Our findings are in line with the general understanding that plowing is a means to reduce the IP of Fusarium spp. in cereal fields. The main inoculum source for F. langsethiae remains unclear. Our results will be useful in the development of forecasting tools to calculate the risk of Fusarium in cereals.

Effects of genotype, soil type, year and fertilisation on sensory and morphological attributes of carrots (Daucus carota L.).

BACKGROUND: The aim of the study was to investigate the effects of variety, soil type and fertilisation, and the interactions between these factors, on yield and quality traits of carrots. RESULTS: Optimum fertilisation levels for yield and quality of grade one roots were found to be between 80 and 160 kg ha(-1) for nitrogen and between 0 and 120 kg ha(-1) for potassium depending on soil type and precipitation. Carrots grown in peat soil had the highest score for sweetness and the lowest scores for negatively associated characteristics such as bitterness, earthy flavour, terpene flavour and firmness. Nitrate content and the amounts of splitted and forked roots were lowest on sandy soil. Variety significantly affected number of grade 1 roots, dry matter, nitrate content and most of the sensory attributes tested. Interactions between variety, soil type and nitrogen fertilisation were found for most of the tested quality characteristics. CONCLUSION: The investigations showed that year and variety had the highest impact on the carrot quality attributes studied, whereas soil type and fertilisation had less influence. Peat soil and moderate fertilisation with N and K gave optimal sensory quality while sand soil gave optimal quality as regards morphological characters like splitting and forking of roots as well as nitrate content.

The influence of a chronic adolescent nicotine exposure on ethanol withdrawal severity during adulthood in C3H mice.

Animal and human studies have shown tolerance, consumption, relapse, and behavioral interactions between ethanol and nicotine, but little is understood about their interaction, especially as it relates to ethanol withdrawal in adulthood for subjects who have an adolescent history of using these drugs. This study investigated nicotine's influence on ethanol withdrawal seizures in two different age groups of male C3H mice. Adolescent and adult male C3H mice, beginning at postnatal day 28 or 70, respectively, were subjected to a 7-day chronic exposure to ethanol only, ethanol plus nicotine, nicotine only, or vehicle treatment. Six weeks later, all the groups were subjected to chronic exposure to ethanol vapors and the severity of their ethanol withdrawal seizures was assessed by handling-induced convulsions. An adolescent exposure to chronic nicotine resulted in an exacerbation of ethanol withdrawal seizures in adulthood. Given this, adolescence may contain a neurophysiological critical period that is sensitive to nicotine and which may result in an altered response to ethanol dependency in adulthood. These findings have serious implications for the long-term consequences following co-abuse of these drugs during adolescence.