Preliminary Study of Control and Biochemical Characteristics of Giant Hogweed (Heracleum sosnowskyi Manden.) Treated with Microwaves

Abstract

There is an urgent need to develop new compensatory and human-safe methods for controlling invasive Heracleum species. This research aimed to determine the effectiveness of H. sosnowskyi control under microwave radiation and biochemical changes in tissues and sap after irradiation. In field experiments in southern Poland, the plants were cut and irradiated with a device generating electromagnetic waves (2.45 GHz, 32.8 kW/m2). The control efficacy of plants in the rosette phase irradiated for 5, 10, or 15 min was 20%, 100%, and 100%, respectively. The control efficacy of plants in the flowering phase irradiated for 7.5 or 15 min was 66% and 100%. The metabolomic analysis of tissues and sap of irradiated H. sosnowskyi showed significant changes, mainly in the content and composition of proteins and sugars. In tissues, the treatments resulted in protein denaturation and significant changes in the metabolism of amino acids and the glyoxylate and galactose pathways. The sap was rich in sugars, glutamic acid, glutamine, homoserine, serine, and methionine. More changes in metabolite levels were observed in the tissues irradiated for 7.5 min. In conclusion, microwave radiation of H. sosnowskyi for longer times, e.g., 10 and 15 min, efficiently controls it.

Microwave Control of Reynoutria japonica Houtt., Including Ecotoxicological Aspects and the Resveratrol Content in Rhizomes

“…So far, the MV control technique has been used against another invasive species—Sosnowski hogweed ( Heracleum Sosnowskyi Manden. )—also after the prior cutting of aboveground biomass and exposure of plants to MV with a frequency of 2.45 GHz and a power density of 30.0 kW/m 2 emitted by the tubular antenna [ 28 ]. In the case of Sosnowski hogweed, 10 min of MV was enough to destroy the plants and effectively prevent their further regrowth.…”

“…In our research, the shoots’ temperature and the substrate’s surrounding surface increased to 85–90 °C after 20.0–25.0 min of MV exposure. At such a high temperature, irreversible biochemical changes occur in plant tissues, i.e., denaturation of proteins and changes in their composition, changes in the composition of carbohydrates, and significant changes in the metabolism of amino acids and the glyoxylate and galactose pathways, which was observed after the use of MV in tissues of Sosnowski hogweed [ 28 ].…”

“…Healthy Japanese knotweed rhizomes obtained on 23 August 2022 from the field population were carefully washed under running water and divided into fragments of various lengths (1.7–20.9 cm) and diameters (1.5–3.2 cm) so that their total weight was 500 ± 2 g. The rhizomes were MV-treated in the laboratory using one antenna emitting MV of the surface power density of 30 kW/m 2 for 2.5, 5.0, 7.5, or 10.0 min. The device was described in detail by Słowiński et al [ 28 ]. Directly after MV, the temperature of the rhizomes was measured with the FLIR E60 thermal imaging camera (FLIR Systems, Inc., Wilsonville, Oregon, USA) and weighed at laboratory balance (Radwag, Radom, Poland, PL) with ±0.01 g accuracy.…”

“…Microwave radiation has garnered interest in environmental studies [ 25 , 26 , 27 ] and has been employed to control giant hogweed populations [ 28 ]. However, the impact of radiation on soil biological activity remains unclear.…”

Condition of Young Japanese Knotweed (Reynoutria japonica Houtt.) Offshoots in Response to Microwave Radiation of Their Rhizomes

“…Research has shown that a single 10 min treatment with microwaves at 2.45 GHz can prevent regrowth of invasive hogweed (Heracleum sp.) for an entire season [23].…”