Abstract

Essential oils (EOs) are becoming an important alternative as seed

decontaminating agents opposite to synthetic seed preservatives due to their antimicrobial

activities. They also inhibit seed germination which may be problematic for

seeds of cultural plants. In the present study, different treatments of wheat ( Triticum

aestivum ) grain with thyme ( Thymus serpyllum ) EO were tested. Wheat grains were

treated with thyme EO for 6, 12 and 24 hours to determine the optimal time of EO

treatment in order to reduce fungal infection of the grain surface and at the same time

preserve high germination rate of seeds and good physiological status of seedlings

during early stages of their growth. Germination rate, fresh mass and length of shoots

and roots, and physiological status of the seedlings were compared according to the

duration of the treatment. The 6 h-EO treatment was the most optimal procedure that

did not affect seed germination, was not harmful for the seedlings and prevented fungal

infections. The thyme EO could potentially be used as a protective agent for wheat

grain intended for sowing and food production.

Keywords

essential oil, germination, seedling growth, thyme, wheat

Abstract

Fungal colonisation in an amphibious plant species from an intermittent

lake may differ significantly among plant specimens growing under contrasting water

regimes. We examined the effect of the presence of surface water on the level of fungal

colonisation in tall plantain ( Plantago altissima L.). We investigated the presence and

abundance of arbuscular-mycorrhizal (AM) structures, dark-septate-endophyte (DSE)

fungal structures, and plant growth parameters. The observed overall frequency of

fungal structures during the vegetative season was relatively high, ranging from 50%

to 90%. Mycorrhizal frequency was little affected by water level fluctuations. However,

it dropped significantly at the end of the season in the senescence phase. The densities

of arbuscules, vesicles, and hyphal coils reached the highest levels in peak season in

June and July. The density of DSE structures, namely microsclerotia, showed similar

dynamics over the season as for AM structures. Mycorrhizal frequency was positively

related to leaf water content.

Keywords

intermittent lake, Plantago altissima , roots, fungal colonisation, arbuscular mycorrhiza, dark septate endophytes

Abstract

Plants can absorb pollutants produced through industrial activities.

In this research, biochemistry and lignin biosynthesis processes are studied in Pinus

nigra and P. eldarica trees, that were exposed to pollutants from Sarcheshmeh copper

complex and from the Kentuiyeh as control area (both Iran). Needles were collected

in areas adjacent to mining factory, where heavy metals (Cu, Zn, Cd and Pb) are

accumulated in higher concentrations than in plants from control areas. Comparison

of the two studied pine species reveals that P. eldarica needles amass heavy metals

27% more than P. nigra . There was a higher content of total phenolic compounds

and flavonoids in needles growing in close vicinities of the mining activity. Lignin

content was similar in both species of pine and remained unchanged regardless of the

pollution level. Higher activities of enzymes in phenylpropanoid pathway in needles

from polluted areas were measured for both pine species. Findings of this study suggest

involvement of general phenylpropanoid pathway in heavy metal resistance of pine

trees. It seems that P. eldarica can accumulate more heavy metals in its needles and

it has greater resistance to pollutants.

Keywords

flavonoids, heavy metals, lignin, phenolic compounds, pollutants

Abstract

Neuromasts are mechanosensory organs found in primarily aquatic vertebrates,

including many species of amphibians, and are arranged as specific patterns

to form the lateral-line system on the head and along the body. We used a hair-cellspecific

fluorescent dye, DiASP, to analyze the distributional pattern of neuromasts in

the lateral line system of live captive-born larvae of the Italian crested newt, Triturus

carnifex (Laurenti, 1768). We confirmed that DiASP presents a safe and accurate alternative

method for non-destructive studies of neuromast ontogeny and distribution

in live amphibians. All newt larvae subjected to analyses survived and no teratogenic

effects of DiASP on their further development were observed. We were able to use

these data to completely characterize the distribution of neuromasts in this species and

to infer the functional significance of this distribution. Cross-species comparison of

general topography points to neuromast arrangement as a conserved trait in urodelans.

Keywords

fluorescent staining, DiASP, neuromasts topography, salamanders

Abstract

The purpose of the national assessment of knowledge (NAK) in Slovenia

is to gather feedback information about how the national educational system works

and what level of educational aims and standards that are prescribed in the national

curriculum is being reached. Thus far, biology has been one of the subjects on the

NAK five times. In our survey, we analysed 119 items taken from the last four NAK

in biology (2009, 2011, 2014, and 2017) in which 18,730 pupils took part. We were

interested in weak and strong sides of the biological knowledge of our pupils at the end

of their primary education. We determined that pupils, in general, possess satisfactory

basic knowledge of biology. The quality of knowledge of all six tested content units

(cell, heredity, and biotechnology; human body; ecology; plants; animals; research,

experiments, reading of tables, graphs, and figures) was not significantly different.

However, pupils showed the least knowledge about cell, heredity, and biotechnology;

therefore, in planning lessons in the future, there should be more emphasis on these

three topics. Pupils showed significantly more knowledge on multiple-choice items

in comparison to half-open-ended items, which was expected. As also expected, they

showed significantly more knowledge on items of the first cognitive level, less on items

of the second cognitive level, and the least on items of the third cognitive level. The

role of the NAK in biology should remain helping teachers in planning their lessons

and, through this, positively influencing pupils’ knowledge.

Keywords

primary education, achievements, knowledge, biology, national assessment of knowledge

Abstract

Regarding architectural adaptations in aquatic plants caused by the velocity

of water flow only scarce, older information is available. When studying different

Myriophyllum spicatum L. specimen architecture in the same water body differences

in individual main axes and branching pattern were detected at the upstream and at the

downstream end of individual plant beds. Samples from these two locations showed

significant differences in architectural composition. At the downstream parts of the

water body individual plants were longer and the number of branches was higher,

which is contributed to flow velocity.

Keywords

Myriophyllum spicatum , architecture of plants, water flow velocity