The variability of phenolic compounds among grape varieties has an important role in selecting winemaking techniques, but the use of phenolic profiles for quality control is still fragmented and incomplete. Given the recent climate change and global warming, biochemical characterisation of secondary metabolites in autochthonous grape varieties is a very important factor for their preservation and sustainable agriculture. Two autochthonous grape varieties from the western Herzegovina region in Bosnia and Herzegovina have been selected for the research targeting at the evaluation of their phenolic profiles, antioxidant activities, and the correlation with oxidoreductase enzymes polyphenol oxidase and Class III peroxidase, in different berry tissues. The obtained results indicate a similar qualitative profile of phenolic compounds in exocarp and mesocarp in both varieties, but their concentrations and antioxidant activity vary significantly. The correlation between phenolic compounds and oxidoreductase enzyme activities in different grape berry tissues is discussed in this article.

Abstract It is known that aquatic macrophytes are an important part of freshwater ecosystems, and that they play a different role in their structure and functioning. Their presence and distribution depends on water temperature and transparency, nutrient content, conductivity, pH, chemical composition and water circulation. Therefore, the goal of our research was to determine the influence and interrelationship of physicochemical parameters of water on the content of photosynthetic pigments in aquatic macrophytes of Lake Necik, in the Ramsar area of Bardača (Republic of Srpska). Content of total chlorophyll (a + b) during the growing season (June–October) ranged from 0.231 to 1.145 mg g−1 FW in Phragmites communis Trin. ex Steud., from 0.061 to 0.541 mg g−1 FW in Salvinia natans L. (All.), from 0.063 to 0.626 mg g−1 FW in Utricularia vulgaris L. and from 0.063 to 0.443 mg g−1 FW in Ceratophyllum demersum L. Research has shown that floating and submerged macrophytes have a lower ratio of chlorophyll a/b compared to emergent hydrophytes, which is most likely the result of stress caused by increased light intensity and temperature. Seasonal variations in the content of photosynthetic pigments indicated that the species Phragmites communis proved to be more tolerant to the stress caused by the influence of various abiotic factors, while Salvinia natans proved to be more sensitive. Spearmon’s correlation coefficient of the physicochemical parameters of water and the concentration of photosynthetic pigments of macrophytes showed a significant influence of certain abiotic factors (temperature, transparency and nutrients) on the content of pigments in the leaves of Phragmites communis, Salvinia natans, Utricularia vulgaris and Ceratophyllum demersum L.

Allelopathy is a unique phenomenon in nature that refers to direct or indirect, positive or negative, impact of one plant (including microorganisms, insects, and herbivores) on another plant through chemical secretions (allelochemicals). Ambrosia artemisiifolia (ragweed) is a well-known invasive plant possessing allelochemicals that have been found to inhibit the growth and development of plants in their immediate environment. This study aimed to determine the allelopathic impact of the aqueous leaf extract isolated from ragweed leaves (concentrated extract, 1:2, 1:4, and 1:8) on seed germination and early seedling growth of barley (Hordeum vulgare L.) and white clover (Trifolium repens L.). The examined aqueous extract of ragweed had a higher inhibitory effect on the germination of white clover seeds compared to barley. The germination of barley seeds was the lowest at the concentrated leaf extract (up to 70%), while the same process in barley seeds was not determined at this concentration. In the other treatments, germination was significantly lower in both examined species compared to the control. Shoot and root growth of both researched species was inhibited in all treatments compared to the control. The obtained results indicate that the aqueous ragweed extract significantly inhibits the growth of roots and shoots of both tested species, which increases the need for more intensive research on this topic.

Allelopathy determines the dynamics of germination, development and growth of plant species in the environment. Therefore, in this study, the allelopathic effect of an aqueous extract isolated from walnut (Juglans regia L.) leaves (concentrated extract, 1:2, 1:4 and 1:8) on the germination percentage, mean germination value and germination rate of wheat (Triticum aestivum L.) and peas was monitored (Pisum sativum L.). Both tested species were sensitive to juglone, but the percentage of germination was significantly lower in wheat (by 80%) compared to peas, so it can be said that this species is more sensitive. The length of roots and shoots of both tested species decreased in proportion to the increase in the concentration of the extract. Monitoring of this biological phenomenon could help to understand the changes in the environment caused by allelochemicals.

In this study, changes in Class III peroxidase (POX) and polyphenol oxidase (PPO) activity in Phragmites australis (Cav.) Trin. Ex Steud. Utricularia vulgaris L. and Salvinia natans (L.) from the Bardača wetland during one vegetation season (June-October) were monitored. The highest activities of soluble and ionic cell wall bound peroxidases (solPOX and ionPOX, respectively) were measured for Phragmites communis (leaf > root > rhizome), followed by Utricularia vulgaris (whole plant), then Salvinia natans (whole plant). The results showed that during the vegetation period (August-September) the activity of solPOX, ionPOX and PPO in Phragmites communis increased, but the activity decreased drastically in October. For Salvinia natans and Utricularia vulgaris, a different seasonal distribution was obtained in the PPO activity, i.e. with a maximum activity during July and a minimum one during September. Different seasonal trends in enzyme activities are probably the result of abiotic stress caused by changing physic-chemical environmental conditions and different adaptive capacities of the studied species to habitat conditions. Correlations between physicochemical environmental parameters and enzyme activities indicate the possibility of using POX and PPO activities as an important bioindicatos of environmental status.

Background: Drought is one of the major abiotic factors leading to diminishing growth, development and productivity of plants worldwide. Considering that germination is the first phase of growth which in large measure determines plant quality and yield, knowing the effects of different factors on this process is of major importance. This paper studies the effect of drought-induced stress on seed germination and seedling growth of Zea mays L. (the Sweet corn and the hybrid Pioneer B23). Methods: The effect of water stress was caused by different concentrations of mannitol: 5%, 10% and 20%. In the control, we used distilled water. The germination test was performed in three trials of 45 seeds each. The germination percentage, germination potential, drought resistance index were calculated at 3, 5 and 7 days. Growth of seedlings and biomass content were calculate at 14 days.Result: The results show significant differences between the variety and hybrid examined. The pioneer B23 seed germinated in larger number and more quickly. The Sweet corn variety seedling growth was completely absent after treatment with mannitol. The observed difference is certainly not just a consequence of higher mannitol concentrations, but also a difference in the water-retention capability of the variety and hybrid studied. 

Previous research has shown that there are allelopathic interactions between plants, releasing allelochemicals for which it is still unknown whether they are randomly generated or transmitted from generation to generation. In this paper, the influence dried ragweed leaves (Ambrosia artemisiifolia L.) aqueous extract of different concentrations: concentrated extract (10%), extract diluted to 1/2 (5%); 1/4 (2.5%) and 1/8 (1.25%) on germination and growth of peas and beans was monitored. The results showed that the increased concentration of ragweed extract inhibited germination, prolonged germination time and decreased the germination index of both test plant species compared to the control. The ragweed extract (concentrated and 1/2) reduced the growth of shoots and roots compared to the control (by more than 50%), with the inhibitory effect being more visible on young pea plants compared to beans. The results of the research showed that the presence of ragweed as a weed in the field significantly reduces the germination and growth of cultivated plants, which is why care should be taken to suppress and remove it in a timely manner.

Ambrosia artemisifolia (ragweed) is an invasive plant species with severe allergenic effects which quickly detects favorable growth conditions and represents a threat to the quality of plant communities. There are still unanswered questions to the allelopathic effects of ragweed on other species, which further complicates the understanding of its compatibility with other plants in both natural and agricultural environment. The paper monitors the allelopathic effects of the aqueous extract isolated from dry ragweed leaves (10, 5, 2.5 and 1.25%) on the germination and growth of corn and wheat. The aquaeous ragweed extracts reduced the germination of corn and wheat down to 70%. The seedling length was inhibited, especially in high concentrations. Wheat appeared to be more tolerant to the extract effect. Corn suffered a larger inhibition effect in terms of root length and seedlings, which suggested that this species was more sensitive. The obtained results imply that the ragweed should be combated in a timely manner in order to avoid its inhibitory effects on the indicator crops.

Abstract In this paper, changes in the content of photosynthetic pigments during the vegetation season in the leaves of Phragmites communis Trin., Salvinia natans (L.) All., Trapa natans L. and Utricularia vulgaris L. in the area of Bardača fishpond (Sinjak pond) were monitored. Physical and chemical characteristics of water are defined in order to determine their association with the content of photosynthetic pigments. The obtained results indicate the specificity in the content of photosynthetic pigments between aquatic macrophytes and significant variations during the vegetation season. The maximum content of pigments was determined in the leaves of the emerged species, while the minimum content was measured in the submerged and floating leaves. The investigated macrophytic species showed a similar trend in the total chlorophyll content during the vegetation period; with two maximums recorded – May and September, while the minimum values were recorded with the senescence process (October). Total chlorophyll and carotenoids were in a negative correlation with temperature, pH, saturation, water transparency and orthophosphate content in water. On the other hand, they were in a positive correlation with the content of nitrates in water. The correlation analysis of the physical and chemical parameters of water quality and the concentration of macrophytes photosynthetic pigments showed a significant influence of certain abiotic factors on the photosynthetic pigments’ content in the leaves of Phragmites communis Trin., Salvinia natans (L.) All., Trapa natans L. and Utricularia vulgaris L.