Allelopathic effect of princess tree (Paulownica tomentosa (thunb.) Steud.) on germination and growth of radicchio

Cilj istraživanja bio je utvrditi alelopatski utjecaj suhog lista carske paulovnije (Paulownia tomentosa (Thunb.) Steud.) na klijavost sjemena i rast klijanaca dvije sorte radiča. U pokusu su istraženi vodeni ekstrakti u koncentracijama 2,5 %, 5 %, 7,5 % i 10 %, te biljni ostatci u posudama s tlom u dozama od 10 i 20 g/kg. Rezultati su pokazali statistički značajan utjecaj vodenih ekstrakata na klijavost, duljinu korijena i izdanka, te svježu i suhu masu klijanaca radiča sorti 'Tržaški salatnik' i 'Palla Rossa'. Povećanjem koncentracije vodenih ekstrakata povećavao se negativni alelopatski utjecaj. Nicanje obje sorte radiča značajno je smanjeno pri obje doze biljnih ostataka, dok je inhibitorno djelovanje zabilježeno i na svježu i suhu masu radiča sorte 'Palla Rossa'. Sorte radiča razlikovale su se u svojoj osjetljivosti na vodene ekstrakte i biljne ostatke. Vodeni ekstrakti pokazali su veći negativni utjecaj od biljnih ostataka.The aim of the study was to determine the allelopathic effect of princess tree (Paulownia tomentosa (Thunb.) Steud.) dry leaves on germination and seedling growth of two radicchio cultivars. Water extracts in concentrations of 2.5%, 5%, 7.5% and 10%, as well as plant residues in soil at doses of 10 and 20 g/kg were investigated in the experiment. The results showed a statistically significant effect of water extracts on germination, root and shoot length, and fresh and dry weight of seedlings of both 'Tržaški salatnik' and 'Palla Rossa' radicchio cultivars. With the increase in water extracts concentration, the negative allelopathic effect increased. Seedling emergence of both radicchio cultivars was significantly reduced at both doses of plant residues, while inhibitory effect was observed on both fresh and dry weight of radicchio cultivar 'Palla Rossa'. Radicchio cultivars differed in their sensitivity to water extracts and plant residues. Water extracts showed a greater negative impact than plant residues