Are microconidia infectious principles in Neonectria ditissima?

Journal of Plant Diseases and Protection - Comparative studies of different isolates of Neonectria ditissima obtained from canker lesions and rotten fruit showed that both five-septate macroconidia...     

淹水土壤有机酸积累与秸秆碳氮比及氮供应的关系

有机酸积累和毒害是稻田秸杆还田中受到广泛关注的问题。本文以水稻与小麦秸杆为材料，采用淹水培养研究了甲酸、乙酸、丙酸及丁酸在士壤中的积累及其与秸秆碳氮比、氮肥添加量的关系。结果表明，在不施用氮肥的情况下。随秸秆用量的增加，秸秆处理的有机酸积累均显著增多。与稻秸处理相比，麦秸处理的有机酸（尤其足丙酸）积累量显著较高，土壤溶液中NH4^＋浓度显著较低。加入尿素明显减少有机酸积累，促进CH4排放，但对CO2的排放无显著影响；氮素的影响在麦秸处理中表现的尤为明显。上述结果说明麦秸的高碳氮比增加了无机氮的生物固定，抑制有机酸向CH4转化，从而导致麦秸处理有机酸积累量高于稻秸处理。施用氮肥是减少麦秸还田后有机酸积累的有效措施之一，但此措施将可能促进CH4的排放。     

Influence of storage practices on acrylamide formation during potato frying

A number of parameters linked to storage of potatoes were evaluated with regard to their potential to influence the acrylamide formation in French fries. Acrylamide, which is a potential human carcinogen, is reported to be formed during the frying of potatoes as a result of the reactions between asparagine and reducing sugars. This study was conducted using three potato varieties (Bintje, Ramos, and Saturna) typically used in Belgium, The Netherlands, and the northern part of France for French fry and crisp production. Saturna, mainly used in crisp production, appeared to be the least susceptible for acrylamide formation during frying. Especially storage at low temperatures (4 degrees C) compared to storage at 8 degrees C seemed to enhance acrylamide formation due to a strong increase in reducing sugars caused by low-temperature storage. Because of the reversible nature of this physiological reaction, it was possible to achieve a significant reduction of the reducing sugars after a reconditioning of the cold-stored potatoes for 3 weeks at 15 degrees C. All changes in acrylamide concentrations could mainly be explained by the reducing sugar content of the potato (R2 = 0.84, n = 160). This means that, by ensuring a low reducing sugar content of the potato tuber, the risk for acrylamide formation will largely be reduced. Finally the use of a sprout inhibitor did not influence the composition of the potato, and thus acrylamide formation was not susceptible to this treatment.     

Faster anaerobic decomposition of a brittle straw rice mutant: Implications for residue management

Rice (Oryza sativa) in Asia is typically grown on submerged soils in intensive cropping systems with only a brief interval between harvest of one crop and planting of the next. Incorporation of crop residues can be challenging because the fallow period between crops is often too short to allow sufficient decomposition. During early stages of anaerobic residue decomposition in flooded soils, plant growth may be inhibited by nutrient immobilization or by the production of potentially toxic organic acids. Straw from a brittle stem mutant of rice (Oryza sativa L. var. IR68) was tested in a 30-d incubation experiment under continuously flooded conditions in a greenhouse to determine if it would decompose more rapidly than the non-brittle phenotype, thereby allowing shorter fallow time between crops. Brittle straw decomposed faster, as indicated by 51% total C loss as CO₂ or CH₄ within 3 weeks of incorporation, compared with 28% for non-brittle straw. However, brittle straw also produced a significantly higher (P<0.0001) amount of formic, acetic, aconitic, propionic, and butyric acids than non-brittle straw. There was no difference in soil N immobilization pattern between the two straw types, or in P or K availability in the soil, perhaps due to the short duration of the experiment. To maximize the potential advantage of faster decomposition of brittle straw in intensive rice cropping systems, it may be helpful to manage water for sufficient soil aeration to mitigate the negative organic acid and methane production effects.     

Camera steered mechanical weed control in sugar beet,maize and soybean

In sugar beet, maize and soybean, weeds are usually controlled by herbicides uniformly applied across the whole field. Due to restrictions in herbicide use and negative side effects, mechanical weeding plays a major role in integrated weed management (IWM). In 2015 and 2016, eight field experiments were conducted to test the efficacy of an OEM Claas 3-D stereo camera^® in combination with an Einböck Row-Guard^® hoe for controlling weeds. Ducks-foot blades in the inter-row were combined with four different mechanical intra-row weeding elements in sugar beet, maize and soybean and a band sprayer in sugar beet. Average weed densities in the untreated control plots were from 12 to 153 plants m^?2 with Chenopodium album, Polygonum convolvulus, Thlapsi arvense being the most abundant weed species. Camera steered hoeing resulted in 78% weed control efficacy compared to 65% using machine hoeing with manual guidance. Mechanical intra-row elements controlled up to 79% of the weeds in the crop rows. Those elements did not cause significant crop damage except for the treatment with a rotary harrow in maize in 2016. Weed control efficacy was highest in the herbicide treatments with almost 100% followed by herbicide band-applications combined with inter-row hoeing. Mechanical weed control treatments increased white sugar yield by 39%, maize biomass yield by 43% and soybean grain yield by 58% compared to the untreated control in both years. However, yield increase was again higher with chemical weed control. In conclusion, camera guided weed hoeing has improved efficacy and selectivity of mechanical weed control in sugar beet, maize and soybean.     

Physicochemical and Biological Characterization of Fucoidan from Fucus vesiculosus Purified by Dye Affinity Chromatography

A comparative study concerning the physicochemical, monomeric composition and biological characters among different fucoidan fractions is presented. Common purification techniques for fucoidan usually involve many steps. During these steps, the important structural features might be affected and consequently alter its biological activities. Three purified fractions were derived from Fucus vesiculosus water extract which, afterwards, were purified by a recently-developed dye affinity chromatography protocol. This protocol is based on dye-sulfated polysaccharide interactions. The first two fractions were obtained from crude precipitated fucoidan at different pH values of the adsorption phase: pH 1 and 6. This procedure resulted in fucoidan_1 and 6 fractions. The other, third, fraction: fucoidan_M, however, was obtained from a buffered crude extract at pH 1, eliminating the ethanol precipitation step. All of the three fractions were then further evaluated. Results revealed that fucoidan_M showed the highest sulfur content (S%), 12.11%, with the lowest average molecular weight, 48 kDa. Fucose, galactose, and uronic acid/glucose dimers were detected in all fractions, although, xylose was only detected in fucoidan_1 and 6. In a concentration of 10 µg·mL⁻¹, Fucoidan_6 showed the highest heparin-like anticoagulant activity and could prolong the APTT and TT significantly to 66.03 ± 2.93 and 75.36 ± 1.37 s, respectively. In addition, fucoidan_M demonstrated the highest potency against HSV-1 with an IC₅₀ of 2.41 µg·mL⁻¹. The technique proved to be a candidate for fucoidan purifaction from its crude extract removing the precipitation step from common purification protocols and produced different fucoidan qualities resulted from the different incubation conditions with the immobilized thiazine toluidine blue O dye.     

Pesticide exposure assessment for surface waters in the EU. Part 1: Some comments on the current procedure

In 2001, the European Commission introduced a risk assessment project known as FOCUS (FOrum for the Coordination of pesticide fate models and their USe) for the surface water risk assessment of active substances in the European Union. Even for the national authorisation of plant protection products (PPPs), the vast majority of EU member states still refer to the four runoff and six drainage scenarios selected by the FOCUS Surface Water Workgroup. However, our study, as well as the European Food Safety Authority (EFSA), has stated the need for various improvements. Current developments in pesticide exposure assessment mainly relate to two processes. Firstly, predicted environmental concentrations (PECs) of pesticides are calculated by introducing model input variables such as weather conditions, soil properties and substance fate parameters that have a probabilistic nature. Secondly, spatially distributed PECs for soil–climate scenarios are derived on the basis of an analysis of geodata. Such approaches facilitate the calculation of a spatiotemporal cumulative distribution function (CDF) of PECs for a given area of interest and are subsequently used to determine an exposure concentration endpoint as a given percentile of the CDF. For national PPP authorisation, we propose that, in the future, exposure endpoints should be determined from the overall known statistical PEC population for an area of interest, and derived for soil and climate conditions specific to the particular member state. © 2016 Society of Chemical Industry     

Sprouting Ability and Seasonal Changes of Sugar Concentrations in Rhizomes of Calystegia sepium and Roots of Convolvulus arvensis

Journal of Plant Diseases and Protection - Factors influencing the sprouting ability of rhizome pieces of Calystegia sepium and root pieces of Convolvulus arvensis were analyzed in four...     

Characterization and mapping of a QTL derived from Solanum habrochaites associated with elevated rutin content (quercetin-3-rutinoside) in tomato

Consumption of flavonoids found in fruits and vegetables is linked to beneficial health outcomes. Tomato is among the most widely consumed and economically important vegetables worldwide and improvement of the nutrient content could lead to significant health benefits. Rutin, (quercetin-3-rutinoside), the main flavonol in tomato fruit, is confined to the peel. Rutin synthesis is limited by low expression of chalcone isomerase, the enzyme catalyzing the conversion of naringenin chalcone to naringenin quercetin. The wild tomato species Solanum habrochaites is a major source of new alleles to improve cultivated tomato (Solanum lycopersicum). AVRDC—The World Vegetable Center identified introgression line (IL) LA3984 containing a segment of S. habrochaites on chromosome 5 expressing high levels of rutin in full red ripe fruit. An AVRDC high rutin tomato line evaluated for 2 years and two seasons in Taiwan produced mean rutin content about four- to five-fold greater than the mean of all entries and about 11–12 times higher than the commercial fresh market and processing tomato cultivars. The quantitative trait locus (QTL) conditioning high rutin content was mapped to a 0.42 Mb segment on chromosome 5 flanked by markers c2_At3g55120/TaqI and ch05-4.883/ApaLI. Marker c2_Atg55120 overlaps with the chalcone-flavonone isomerase gene Solyc05g10320, and a second chalcone-flavonone isomerase gene is located 3,000 bp upstream from c2_At3g551220. Results of this project will facilitate breeding of high flavonoid tomato lines.     

Vertical distribution of soil properties under short‐rotation forestry in Northern Germany

Short‐rotation forestry (SRF) on arable soils has high potentials for biomass production and leads to long‐term no‐tillage management. In the present study, the vertical distributions of soil chemical and microbial properties after 15 y of SRF with willows and poplar (Salix and Populus spp.) in 3‐ and 6‐year rotations on an arable soil were measured and compared to a pertinent tilled arable site. Two transects at different positions in the relief (upper and lower slope; transect 1 and 2) were investigated. Short‐rotation forestry caused significant changes in the vertical distribution of all investigated soil properties (organic and microbial C, total and microbial N, soil enzyme activities), however, the dimension and location (horizons) of significant effects varied. The rotation periods affected the vertical distribution of the soil properties within the SRF significantly. In transect 1, SRF had higher organic‐C concentrations in the subsoil (Bv horizon), whereas in transect 2, the organic‐C concentrations were increased predominantly in the topsoil (Ah horizon). Sufficient plant supply of P and K in combination with decreased concentrations of these elements in the subsoil under SRF pointed to an effective nutrient mobilization and transfer from the deeper soil horizons even in the long term. In transect 1, the microbial‐C concentrations were higher in the B and C horizons and in transect 2 in the A horizons under SRF than under arable use. The activities of β‐glucosidases and acid phosphatases in the soil were predominantly lower under SRF than under arable use in the topsoil and subsoil. We conclude, that long‐term SRF on arable sites can contribute to increased C sequestration and changes in the vertical distribution of soil microbial biomass and soil enzyme activities in the topsoil and also in the subsoil.