| Abstract [eng] |
Alternative antifungal materials are very important for controlling diseases with high economic significance, such as strawberry grey mould, caused by Botrytis cinerea. This pathogen can affect a wide range of plant hosts, and the widespread application of fungicides and the development of pathogen resistance has led researchers to look for novel alternative methods of controlling grey mould during plant growth and storage. Clove (Syzygium aromaticum) extracts and essential oils have antimicrobial, antifungal and antioxidant activity due to high concentrations of secondary metabolites. Although the application of clove bud extracts appears to be effective in controlling fungal plant diseases, little is known about how plants react to other plant–based compounds used for protection. Environmental stress, both biotic and abiotic, induces changes in the antioxidant system of plants. While there are separate reports on the antifungal properties and antioxidant activity of essential oils and plant extracts, comprehensive studies that evaluate antifungal activity, impact on the plant antioxidant system, and the synthesis of secondary metabolites during the growth of plants are still lacking. This research investigated how clove extract affected strawberry plants’ antioxidant system along with the ability of this extract to prevent gray mould in strawberries. Firstly, the ability of subcritical CO2 clove bud extract to inhibit grey mould (Botrytis cinerea) infection in strawberry leaves during growth in a controlled environment was examined. Secondly, the antioxidant activity in the leaves of both healthy and gray mould damaged strawberry leaves was evaluated at different stages of the experiment using ABTS, DPPH and FRAP methods to determine how plants responded to clove bud extract. It was also determined how the concentrations of phenolic compounds, chlorophyll a, b and carotenoids changed in the plants. Results revealed that clove extract at a dosage of 0,20 % minimally inhibited infection caused by B. cinerea in the leaves of strawberry plants cultivated in a greenhouse. Increasing ABTS antioxidant activity, reducing DPPH antioxidant activity and changing FRAP antioxidant activity was observed and different experimental periods in strawberries exposed to the extract, both healthy and gray mould infected. When evaluating concentration of carotenoids, chlorophylls, and total phenolics, an overall changing tendency was also observed. Throughout the study, the concentration of these substances decreased from higher values in both healthy and gray mould damaged strawberries. It can be concluded that, even though clove bud extract minimally inhibited grey mould during strawberry growth, it did not have negative impact on secondary metabolite concentrations or the activity of the strawberry antioxidant system, and it has a high potential for further antifungal research and application. |
