Diversity of Mycobiota Associated with the Cereal Cyst Nematode Heterodera filipjevi Originating from Some Localities of the Pannonian Plain in Serbia.

Cereals, particularly wheat, are staple food of the people from the Balkans, dating back to the Neolithic age. In Serbia, cereals are predominantly grown in its northern part between 44° and 45.5° N of the Pannonian Plain. One of the most economically important nematodes on wheat is the cereal cyst nematode, Heterodera filipjevi. Cysts of H. filipjevi survive in soil for years and shelter a large number of microorganisms. The aims of this study were to investigate the diversity of mycobiota associated with the cereal cyst nematode H. filipjevi, to infer phylogenetic relationships of the found mycobiota, and to explore the ecological connection between fungi and the field history, including the potential of fungi in bioremediation and the production of novel bioactive compounds. Cysts were isolated from soil samples with a Spears apparatus and collected on a 150-µm sieve. The cysts were placed on potato dextrose agar, and maintained for two weeks at 27°C. Following fungal isolation and colony growing, the fungal DNA was extracted, the ITS region was amplified, and PCR products were sequenced. The study showed that the isolated fungal species belong to diverse phyla, including Ascomycota, Basidiomycota, and Mucoromycota. Ascomycota is represented by the families Clavicipitaceae, Sarocladiaceae, Nectriaceae, and Phaeosphaeriaceae. Basidiomycota is represented by the families Cerrenaceae, Polyporaceae, Phanerochaetaceae, and Meruliaceae, and the order Cantharellales. The family Mortierellaceae represents Mucoromycota. The members of Ascomycota and Basidiomycota both depict the field history. Ascomycota indicate the fungal infection is of recent origin, while Basidiomycota point toward the preceding host plants, enabling the plant field colonization history to be traced chronologically.

New insights in dehydration stress behavior of two maize hybrids using advanced distributed reactivity model (DRM). Responses to the impact of 24-epibrassinolide.

Proposed distributed reactivity model of dehydration for seedling parts of two various maize hybrids (ZP434, ZP704) was established. Dehydration stresses were induced thermally, which is also accompanied by response of hybrids to heat stress. It was found that an increased value of activation energy counterparts within radicle dehydration of ZP434, with a high concentration of 24-epibrassinolide (24-EBL) at elevated operating temperatures, probably causes activation of diffusion mechanisms in cutin network and may increases likelihood of formation of free volumes, large enough to accommodate diffusing molecule. Many small random effects were detected and can be correlated with micro-disturbing in a space filled with water caused by thermal gradients, increasing capillary phenomena, and which can induce thermo-capillary migration. The influence of seedling content of various sugars and minerals on dehydration was also examined. Estimated distributed reactivity models indicate a dependence of reactivity on structural arrangements, due to present interactions between water molecules and chemical species within the plant.

Stimulative influence of germination and growth of maize seedlings originating from aged seeds by 2,4-D potencies.

BACKGROUND: The 2,4-D (2,4-dichlorophenoxyacetic acid) is using as a growth regulator in tissue culture media. Maize seeds have poor ability to maintain germination rate in the long term. OBJECTIVE: To examine the possible restorative effect of homeopathic 2,4-D potencies on maize seedlings originating from seeds damaged by accelerated aging. METHODS: Seeds of four maize lines were subjected to accelerated aging stress treatment. Seed samples were treated with distilled water (control) and a range of potencies of 2,4-D: 3C, 3.75C, 4.5C, 5.25C and 6C. The germination capacity, fresh substance (FS) and length of root and shoot were determined. Hydrolysis and biosynthesis, GSH/GSSG ratio and redox capacity were calculated. RESULTS: Induced seed aging decreased germination rate and growth of seedlings. 2,4-D potencies did not have a statistically significant effect on germination. However, there were statistically significant effects on FS production, root and shoot length and redox capacity. The 3C potency had the largest effect on the FS accumulation, 4.5C increased root and shoot length, compared to control (statistically significant). The GSH/GSSG ratio and the redox capacity were decreased by aging. The 3C and 4.5C potencies tended to reverse the GSH/GSSG ratio (statistically significant) in the root and shoot, (i.e., shifted the redox balance to the reduced state). CONCLUSION: Homeopathic potencies of 2,4-D appear to have a beneficial effect on artificially aged maize seeds: they stimulate growth through better substance conversion from seed rest, and shift the redox capacity towards a reduced environment. Further work is required to determine if this is an useful means of improving maize seed germination and growth.