The effects of leaf extracts of crack willow (Salix fragilis) on the growth of Japanese knotweed (Fallopia japonica) | Vpliv listnih izvlečkov krhke vrbe (Salix fragilis) na rast japonskega dresnika (Fallopia japonica)

English. Japanese knotweed (Fallopia japonica) is one of the most invasive of species in Europe, and can substantially reduce local native biodiversity. In the present study, the allelopathic potential of crack willow (Salix fragilis) on growth of Japanese knotweed was investigated.Aqueous extracts of 0.1% and 1% (w/v) were prepared from liophilised willow leaves and used for watering of young knotweed plants. Their growth was monitored for 196 days. Shoot height and leaf number were not affected but the mass of leaves and especially roots was reduced (up to 32%). At the end of experiment, biochemical characteristics related to physiological state (photochemical efficiency of PSII, protein content, enzyme activity of guaiacol peroxidase, lipid peroxidation) were measured. Mostly, they were at control levels, but the activity of guaiacol peroxidase and lipid peroxidation in roots increased. The extracts of crack willow showed moderate inhibitory effect on roots of treated knotweeds while the growth of shoots was unaffected. Given the root reduction described here, further studies with willow extracts and field studies with crack willow and Japanese knotweed plants would be reasonable.

Slovenian. Japonski dresnik (Fallopia japonica) sodi med najbolj inavzivne tujerodne vrste v Evropi in pomembno vpliva na zmanjševanje lokalne biodiverzitete. V raziskavi smo preučili alelopatski potencial krhke vrbe (Salix caprea) na rast japonskega dresnika. Iz liofiliziranih listov vrbe smo pripravili 0,1 % in 1 % vodne izvlečke, s katerimi smo zalivali mlade rastline dresnika in spremljali njihovo rast 196 dni. Višina poganjkov in število listov sta bila podobna kot v kontrolnem tretmaju, medtem ko se je masa listov, predvsem pa korenin, močno zmanjšala (do 32 %). Ob koncu poskusa smo z biokemijskimi analizami (fotokemična učinkovitost FSII, vsebnost beljakovin, encimska aktivnost gvaiakol peroksidaze, lipidna peroksidacija) ocenili še fiziološko stanje rastlin. Večina izmerjenih lastnosti je bila na kontrolni ravni, razen peroksidazne aktivnosti in lipidne peroksidacije, ki sta se pri tretiranih rastlinah povečali. Izvlečki krhke vrbe kažejo zmeren alelopatski učinek na korenine tretiranih dresnikov, medtem ko so poganjki rasli neprizadeto. Glede na opisano zmanjšanje koreninskega sistema predlagamo nadaljnje raziskave z izvlečki vrbe in terenske raziskave o vplivu krhke vrbe na rast japonskega dresnika.