Growth of seeds of the invasive species Heracleum sosnowskyi, Umbelliferae

Maryia MISHYNA1, Nikolai LAMAN2, Valery PROKHOROV2 & Yoshiharu FUJII1
Tokyo university of agriculture and technology, Tokyo, Japan
Institute of experimental botany, Minsk, Belarus

Heracleum sosnowskyi was introduced in the countries of eastern Europe where, due to favourable conditions for growth and development in the main areas of introduction invaded large areas, leading to the active exclusion of native species and thus reduced biological diversity. Annually on the territory of Belarus and neighboring countries the area of its population increases by more than 10 percent. One reason for the rapid expansion and high invasiveness of alien plant species is their allelopathic activity. In particular, at the stage of germination of seeds, allocating exometabolites create around themselves a biochemical and microbiological environment and in the early stages of ontogeny between them a phytocenotic relationship is established. Part of the research of allelopathic activity of Heracleum sosnowskyi is to study the influence of substances released by swelling of its mericarps, fruit cover and seeds on primary growth of Vicia sativa L. seedlings. Joint germination Vicia sativa cv. Natalie with swelling mericarps of Heracleum sosnowskyi resulted in a significant increase of the epicotyl length of seedlings on 2,7-22,8% relative to control (P = 0,0056). Substances from the fruit cover significantly inhibited the primary growth of epicotyl (3,71 ± 0,38 cm) and roots (3,29 ± 0,25 cm) that were 30,9-52,6% and 14,5-42,1% compared with the control respectively. Also noted was a slight trend toward inhibition by Heracleum sosnowskyi seeds without fruit cover the growth of seedlings of Vicia sativa. The length of epicotyl was 3,5-9,2% and the length of the roots - 4,9-19,6% compared with control (P = 0,0097). Thus it was shown that the compounds of inhibitory nature in the seeds of Heracleum sosnowskyi mainly localize in the fruit cover. Probably the mechanism of action of these substances is due to inhibition of the processes of division and differentiation of cells in the early stages of ontogeny. These studies facilitate further study of Heralceum sosnowskyi allelopathic characteristics, as a factor of high invasiveness.

© 2012 Organizing Committee