Laboratory of Basic Research in Horticulture, Faculty of Horticulture and Landscape Architecture, Warsaw University of Life Sciences, Nowoursynowska 159, 02–776 Warsaw, Poland.
*Correspondence author: E-mail: helena_gawronska@sggw.pl
This paper is the second of two parts describing the allelopathic potential of sunflower. This study aimed to: (i) determine the allelopathic activity of volatiles, root exudates, leachates and extracts of sunflower (Helianthus annuus L.) cv. ‘Ogrodowy’ and (ii) check whether soil after sunflower cultivation exhibit allelopathic activity. Acceptors of the allelochemicals were seeds and seedlings of mustard (Sinapis alba L.) cv. ‘Nakielska’.
Allelopathic compounds of sunflower origin, irrespective of their mechanism of release mostly, exerted the inhibitory allelopathic effects on the acceptor plants. The sunflower leaf volatiles, extracts or leachates reduced the germination of mustard. Allelochemicals contained in the shoot and in the seedling exudates had negative effects on seedlings of acceptor plants (weak, stunted and had low fresh weight). The inhibitory effects were greater for volatiles released by chopped than intact leaves and for the allelochemicals extracted than leached from fresh leaves. The inhibitory effects were greater in combined exudates and volatiles. Growth of mustard plants was strongly inhibited by some compounds that were present in the soil from the preceding sunflower crop.
Extract, exudates, germination, Helianthius annus L., leachates, phytotoxicity, seedling growth, Sinapis alba L., volatiles
