Paraffin oil induces resistance against powdery mildew in grapevine through salicylic acid signaling.

BACKGROUND: Mineral oils have been widely used in the pest control of several crops. However, their mode of action is poorly understood, especially in the case of their antifungal properties. The possible direct fungicidal activity and the stress-inducing capability of paraffin oil on grapevine were examined using Vitis vinifera L. cv 'Kékfrankos' cuttings and the fungus Erysiphe necator, the causal agent of powdery mildew. RESULTS: Our experiments demonstrated that paraffin oil does not have fungicide activity on E. necator, but induces significant stress-related changes in grapevine physiology. Elevated H2 O2 production and the accumulation of the phytohormone salicylic acid were measured. Secondary thickening of the cell wall by lignin deposition and the accumulation of phenolic compounds were also observed. Some enzyme activities related to the detoxification of reactive oxygen species, disease response, and the synthesis of lignin were changed in accordance with the determined changes in cell wall composition and H2 O2 levels. CONCLUSION: The results suggest that paraffin oil induces stress responses on grapevine leaves through oxidative burst, and this response is systemized by salicylic acid. The accumulation of lignin and water-soluble phenolics may be directly responsible for the paraffin oil-induced resistance of grapevine against powdery mildew. © 2021 Society of Chemical Industry.

Newly Grown Wool Mineral Content Response to Dietary Supplementation in Sheep.

Determination of wool mineral content to assess the animal' mineral status has been extensively used, but the results are controversial. One of the possible contributing factors is that the sampling material in previous studies was collected from a long staple, a fact that could mask the response to recent differences in mineral intake. Therefore, the aim of the present study was to test the sensitiveness of newly grown wool to different dietary mineral intake. Twenty Tsigai ewes were allocated into five dietary treatments with similar hay and concentrate intake but different premix inclusion rates in the concentrate (3, 4, 5, 6, and 7%). Wool was sampled on the left side from a 5 × 5 cm area using bent scissors at the beginning of the trial and from the very same area 28 days later. Samples after cleaning and mineralization were analyzed with ICP-OES (Perkin-Elmer, Optima 3300 DV) for calcium, phosphorus, magnesium, sodium, selenium, zinc, copper, and sulfur content. Long fleeces had significantly lower Ca and Se content compared to the newly grown wool samples of the group at the premix manufacturer's suggested level of supplementation (5%). Macrominerals in fresh wool did not respond to increased dietary supplementation. Se and Zn content of wool had a strong relationship with the daily intake (R2 = 0.95 and R2 = 0.97, respectively.) In conclusion, the mineral content of long fleeces can be different compared to recently developed wool fiber. This indicates that, in some cases, analyzing long staples for mineral status can be misleading. Our results showed that wool could be a sensitive indicator of low selenium and high zinc intake. Mineral interactions can significantly affect the actual availability of trace minerals; therefore, a more careful design of premixes is needed. The described method seems to be applicable in livestock farming, but the mineral interactions that may alter the results need to be further explored.

Would fertilization history render the soil microbial communities and their activities more resistant to rainfall fluctuations?

Water stress and nutrient supply are two of the most ubiquitous global changes that surely drive substantial variations not only in agricultural productivity but also extend to alert soil living organisms. The present study aims to understand the intrinsic changes in the composition of soil populations and their functions due to the interaction between long-term fertilization and rainfall fluctuations, seeing whether fertilization history would render the soil microbial communities and their activities more resistant to water stress or not. The experiment was established in 1988 on a typical meadow soil (Vertisols) as a rainfed maize monoculture receiving six elevated rates of NPK annually. The 30-year average annual precipitation of the growing season in this region is 345.1 mm. However, in 2010 rainfall was 106.1% greater than the average, while in 2011 it was 26.5% lower. The results show that long-term NPK fertilization has made the soil microbes more tolerant to changes in soil moisture content resulting from rainfall fluctuations. Soil microbes and their activities, however, did not follow a dose-response relationship of NPK as soil moisture content was the main driving factor. Numbers of total fungi, cellulose decomposing bacteria, and nitrifying bacteria increased as rainfall in 2010 increased. Moreover, microbial biomass carbon in 2010 was almost 2-fold higher than in 2009. Soil respiration in 2010 was 11 and 35% higher than in 2009 and 2011, respectively. Otherwise, high rainfall in 2010 significantly diminished soil NO3- content and nitrification rate. Soil enzyme activity showed a higher response to soil moisture than the rate of NPK. The highest activity of phosphatase, dehydrogenase, and saccharase was measured in the driest year (2011), while urease displayed its highest activity in 2010. High rates of NPK significantly reduced soil dehydrogenase activity. These results illustrate how important it is for fertilizer programs to be flexible to match expected climate change in order to improve productivity and reduce environmental pollution.

Effect of herbicides on soil respiration: a case study conducted at Debrecen-Látókép Plant Cultivation Experimental Station.

Measuring the effect of herbicides on the natural environment is essential to secure sustainable agriculture practices. Amount of carbon dioxide released by soil microorganisms (soil respiration) is one of the most important soil health indicators, known so far. In this paper we present a comprehensive quantifying study, in which we measured the effect of 14 herbicides on soil respiration over 16 years, from 1991 to 2017, at Debrecen-Látókép Plant Cultivation Experimental Station. Investigated herbicides contained different active ingredients and were applied in various doses. It was found that 11 out of the examined 14 herbicides had a detrimental effect on soil respiration.

Study of phosphate species of chernozem and sand soils by heterogeneous isotope exchange with 32P radioactive tracer.

Weakly and tightly sorbed phosphate species on chernozem and humus sand are investigated by radioactive tracer method using 32P. The comparison of the heterogeneous isotope exchange of 32P-labeled phosphate of non-radioactively incubated soils and desorption of 32P-labeled phosphate of radioactively incubated soils shows the transformation of weakly sorbed species to tightly sorbed ones. The quantity of weakly sorbed phosphorus and the steady state phosphorus exchange rate between soil and soil solution, transformation half-life of weakly to tightly sorbed phosphate are calculated.