Trichoderma as a biostimulator and biocontrol agent against Fusarium in the production of cereal crops: Opportunities and possibilities

Despite technological advances in global agriculture in recent years, the problem of pathogenic fungi in the production of cereal crops continues to be an issue. Currently, the high variability of weather factors that are considered unusual for specific locations affect the growth and physiology of pathogens attacking cereal crops. One of the most common plant protection methods is the use of synthetic pesticides; however, there is growing controversy over this approach due to the build-up of pesticides in the environment and the presence of their residues in food. The purpose of this literature review is to explore the current state of knowledge regarding the potential of using Trichoderma species as a biostimulator and for the biological protection of cereal crops against pathogenic fungi. Trichoderma fungi—through mycoparasitism, antibiosis and competition for space and nutrients—help to inhibit the growth of pathogens and have a positive impact on the growth of plants, including their root system, which is considered a desirable effect during drought episodes. It has also been demonstrated that Trichoderma fungi can convert Fusarium toxins into new metabolites that can be of lower toxicity. However, the highly limited number of in vivo studies investigating the use of these fungi for biocontrol in cereal crops remains an obstacle to the commercialization of Trichoderma fungi. It appears that the determination of their effectiveness in the biocontrol of cereal crops under variable weather and climate conditions presents a considerable challenge.     

Quantitative trait loci mapping of freezing tolerance and photosynthetic acclimation to cold in winter two‐ and six‐rowed barley

Photoacclimation (PA) and freezing tolerance (FT) have been identified as closely related traits, due to common mechanisms of environmental control. In this study, diversity array technology (DArT) was used for identification of the quantitative trait loci (QTL) of FT and PA in winter barley. Simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers were subsequently used to saturate QTL regions. Two F₂ mapping populations were created, for two‐rowed (P44) and six‐rowed barley (CaP). Different regions of the genome were responsible for differences in traits between parents in these two populations. Eleven QTLs were identified in the P44 population, including five typical for FT and PA, on chromosomes 2H, 3H and 7H. In the CaP population, only one QTL connected with PA and 10 connected with FT were found on all chromosomes except 2H. Our results demonstrate that different sets of markers should be applied in marker‐assisted selection for FT in two‐ and six‐rowed barley, as several loci determine FT at the level of biparental crosses.     

Visual and quantitative electroencephalographic analysis of healthy young and adult cats under medetomidine sedation

A study was designed to investigate the effect of medetomidine sedation on quantitative electroencephalography (q-EEG) in healthy young and adult cats to determine objective guidelines for diagnostic EEG recordings and interpretation. Preliminary visual examination of EEG recordings revealed high-voltage low-frequency background activity. Spindles, k-complexes and vertex sharp transients characteristic of sleep or sedation were superimposed on a low background activity. Neither paroxysmal activity nor EEG burst-suppression were observed. The spectral analysis of q-EEG included four parameters, namely, relative power (%), and mean, median and peak frequency (Hz) of all four frequency bands (delta, theta, alpha and beta). The findings showed a prevalence of slow delta and theta rhythms as opposed to fast alpha and beta rhythms in both young (group A) and adult (group B) cats. A posterior gradient was reported for the theta band and an anterior gradient for the alpha and beta bands in both groups, respectively. The relative power value in group B compared to group A was significantly higher for theta, alpha and beta bands, and lower for the delta band. The mean and median frequency values in group B was significantly higher for delta, theta and beta bands and lower for the alpha band. The study has shown that a medetomidine sedation protocol for feline EEG may offer a method for investigating bio-electrical cortical activity. The use of q-EEG analysis showed a decrease in high frequency bands and increased activity of the low frequency band in healthy cats under medetomidine sedation.     

Preliminary reference values for electrocardiography,echocardiography and myocardial morphometry in the European brown hare (Lepus europaeus)

The study aimed at defining reference values for electrocardiographic (ECG) and echocardiographic parameters as well as macroscopic dimensions of the heart and microscopic dimensions of cardiomyocytes in the European brown hare. The studies were conducted on 30 adult, clinically healthy hares of either sex caught in Poland. ECG and echocardiography were performed supravitally on anaesthetized hares. After euthanasia, gross and microscopic myocardial and cardiomyocyte dimensions were determined. Heart rate amounted to 140 ± 37.5 beats/min, the leading rhythm involved the sinus rhythm. P wave time was 26 ± 5 ms, PQ time was 80 ms, QRS time was 29 ± 3.5 ms, and ST was 97.5 ± 7 ms. Echocardiography determined a left ventricular wall end-diastolic diameter of 8.6 ± 2.0 mm and an intraventricular septum end-diastolic diameter of 5.75 ± 1.0 mm. The thickness of the interventricular septum corresponded to that of the free wall of the left ventricle, a finding consistent with physiological hypertrophy. Preliminary reference values were established for echocardiography. The findings were similar to those obtained at necropsy. The ECG and echocardiographic studies represent the first supravital examination of cardiac function in the hare. The obtained results illustrate adaptation of hare''s myocardium to its mode of life. The cardiac findings resemble the athlete''s heart syndrome described in humans. The findings may prove useful in further studies on the physiology of the cardio-vascular system in the hare.     

Differential influence of four invasive plant species on soil physicochemical properties in a pot experiment

Purpose

This study compared the effects of four invasive plants, namely Impatiens glandulifera, Reynoutria japonica, Rudbeckia laciniata, and Solidago gigantea, as well as two native species—Artemisia vulgaris, Phalaris arundinacea, and their mixture on soil physicochemical properties in a pot experiment.

Materials and methods

Plants were planted in pots in two loamy sand soils. The soils were collected from fallows located outside (fallow soil) and within river valley (valley soil) under native plant communities. Aboveground plant biomass, cover, and soil physicochemical properties such as nutrient concentrations, pH, and water holding capacity (WHC) were measured after two growing seasons. Discriminant analysis (DA) was used to identify soil variables responsible for the discrimination between plant treatments. Identified variables were further compared between treatments using one-way ANOVA followed by Tukey’s HSD test.

Results and discussion

Plant biomass, cover, and soil parameters depended on species and soil type. DA effectively separated soils under different plant species. DA on fallow soil data separated R. laciniata from all other treatments, especially I. glandulifera, native species and bare soil, along axis 1 (related mainly to exchangeable K, N-NH₄, total P, N-NO_3, and WHC). Large differences were found between R. laciniata and S. gigantea as indicated by axis 2 (S-SO₄, exchangeable Mg, total P, exchangeable Ca, and total Mg). DA on valley soil data separated R. japonica from all other treatments, particularly S. gigantea, R. laciniata, and native mixture, along axis 1 (N-NO₃, total N, S-SO₄, total P, pH). Along axis 2 (N-NO₃, N-NH₄, Olsen P, exchangeable K, WHC), large differences were observed between I. glandulifera and all other invaders.

Conclusions

Plant influence on soil differed both among invasive species and between invasive and native species. Impatiens glandulifera had a relatively weak effect and its soil was similar to both native and bare soils. Multidirectional effects of different invaders resulted in a considerable divergence in soil characteristics. Invasion-driven changes in the soil environment may trigger feedbacks that stabilize or accelerate invasion and hinder re-colonization by native vegetation, which has implications for the restoration of invaded habitats.

     

Impacts of soil conditions and light availability on natural regeneration of Norway spruce <Emphasis Type="Italic">Picea abies</Emphasis> (L.) H. Karst. in low-elevation mountain forests

? Key message

Natural regeneration of P. abies (L.) H. Karst. may reach high densities in lower mountain elevations. The highest densities were found in sites with moderate light availability, with low pH, and not near the riverbank. However, age-height classes differed in the predicted magnitude of response, but were consistent in response directions. Mosses and understory species typical of coniferous forests were positively correlated with regeneration density.

? Context

Norway spruce Picea abies (L.) H. Karst. in Central Europe is at risk under climate change scenarios, particularly in mountain regions. Little is known about the impact of environmental factors on the natural regeneration of P. abies in low-elevation mountain forests.

? Aims

We aimed to assess impacts of distance from the riverbank, soil pH, and light availability on natural P. abies regeneration. We hypothesized that (1) natural P. abies regeneration would depend on light availability and soil pH and (2) there are understory plant species which may indicate the microsites suitable for natural regeneration of P. abies.

? Methods

The study was conducted in the Sto?owe Mountains National Park (SW Poland, 600–800 m a.s.l.). We established 160 study plots (25 m²) for natural regeneration, light availability, soil pH, and understory vegetation assessment.

? Results

The highest densities of natural regeneration of P. abies were observed in sites with moderate light availability (0.1–0.2 of open sky) and low pH (3.5–4.5), and located relatively far from the riverbank. Cover of 22 understory plant species were correlated with natural P. abies regeneration densities, mostly positively.

? Conclusion

Different stages of natural regeneration of P. abies revealed different regeneration niches. Most understory plant species (bryophytes and herbs typical of coniferous forests) do not compete with natural regeneration of P. abies.

     

Issues related to classification of garden soils from the urban area of Toruń, Poland

ABSTRACT

Nowadays, the city area of Toruń is dominated by anthropogenic and technogenic soils – developed by humans or significantly altered, mainly disturbed in terms of morphology and chemical and physical properties. This study is a continuation of research on the soil cover of the city. The aim of the presented study is to assess extent of garden soils in the city and characterize its properties on the base of five soil profiles in four exemplary gardens in Toruń and evaluate if they meet the classification criteria for Hortic Anthrosols according to World Reference Base (WRB) for Soil Resources. Within the administrative boundaries of the city, 66 allotment gardens are located which totally cover an area of more than 300 ha. They occupy 3% of the city area. None of the studied mineral surface horizons meets the criteria for hortic horizon according to WRB 2015, due to too low phosphorus content. Other hortic criteria were fulfilled. The research on classification issues of garden soils should be continued on larger scale to evaluate if WRB criteria are not too strict taking into account the features of most typical, few decade-old garden soils.     

Does tree-ring formation follow leaf phenology in Pedunculate oak (<Emphasis Type="Italic">Quercus robur</Emphasis> L.)?

We monitored leaf phenology and xylogenesis of 12 Pedunculate oaks in northern Poland in 2014. We hypothesized that the individual trees, which differed in size, age and habitat (tree stand or gap), also diverged in terms of the seasonal patterns of leaf phenology and xylogenesis. The samples used for wood formation observations were collected most frequently during the early leaf phenophases (from March to end of June). The transverse sections of the cambial region were cut with a sledge microtome. We counted the number of cambial cells, measured the width of xylem increment and assessed the timing of xylogenesis and earlywood-vessel formation. We found significant differences in leaf phenology and timing of xylogenesis among individual trees. The smallest differences in wood formation among the trees were observed at the beginning of the vegetation season when the first earlywood vessels were detected (9 days). The dates of completion of the first tangential row of earlywood vessels varied by up to 30 days, while for the completion of the entire earlywood dates varied by up to 32 days. The highest productivity of cambial cells (13 cell layers) was observed around the time of bud swelling at mid-April. In the last days of April, the number of cambial cell layers decreased and subsequently increased again when the leaves were nearly fully expanded at the end of May. To summarize, we observed a high seasonal variability in the number of cambial cell layers. Differences in the time of cessation of cambial activity and xylogenesis amounted to 1 month. We conclude that: (1) oak tree-ring widths and earlywood-vessel sizes and numbers may not be sensitive indicators for early spring temperature and spring defoliation; (2) the missing association between leaf phenophases and xylogenesis as well as the phenological variability may be the reasons for the lack of a clear climatic effect on the above-mentioned parameters.