| Abstract | Na globalnoj razini, invazije alohtonih organizama predstavljaju drugu najveću prijetnju
bioraznolikosti. Pretpostavka je da je visok alelopatski potencijal jedna od značajki koja
pomaţe invazivnim biljnim vrstama u širenju na nova područja. Primjenom vodenih
ekstrakata donor vrsta na test-vrste, u ovom radu dokazan je visok alelopatski potencijal
osam invazivnih alohtonih biljnih vrsta iz šest različitih biljnih porodica: Abutilon
theophrasti Med. - europski mračnjak (porodica Malvaceae), Ambrosia artemisiifolia L. –
pelinolisni limundţik ili ambrozija (Asteraceae), Datura stramonium L. - bijeli kuţnjak
(Solanaceae), Xanthium strumarium L.- dikica (Asteraceae), Ailanthus altissima (Mill.)
Swingle - pajasen (Simaroubaceae), Amorpha fruticosa L. - amorfa (Fabaceae),
Reynoutria japonica Houtt. - japanski dvornik (Polygonaceae), Solidago gigantea Aiton -
velika zlatnica (Asteraceae). Kao test-vrste korištene su tri kultivirane biljne vrste iz tri
različite biljne porodice: Avena sativa L. - zob (Poaceae), Brassica napus subsp. oleifera
L. - uljana repica (Brassicaceae) i Helianthus annuus L. - suncokret (Asteraceae).
Primjenom vodenih ekstrakata donor vrsta na sjeme test-vrsta utvrĎena alelopatska
djelovanja isključivo su negativna tj. inhibirajuća, a intenzitet ovisi o donor vrsti i test-vrsti.
Alelopatski utjecaj na postotak klijavosti kod svih interakcija donor vrsta i test-vrsta je
puno manji u odnosu na utjecaj na duljinu korjenčića i duljinu klice test-vrsta. UtvrĎeno je
da višegodišnje vrste posjeduju jači alelopatski potencijal od jednogodišnjih. Vrsta
najjačeg alelopatskog potencijala je pajasen, a najosjetljivija test-vrsta je uljana repica.
Ekstrakt pajasena inhibirao je duljinu korjenčića uljane repice 94,88%, a duljinu klice
98,91%, što je gotovo herbicidni učinak. Primjenom vodenih ekstrakata korijena, stabljike,
lista i čitave biljke pajasena na sjeme, list i korijen uljane repice utvrĎena su inhibitorna
alelopatska djelovanja različitih intenziteta, ovisno o vrsti i koncentraciji ekstrakta i načinu
primjene. Najjače djelovanje zabiljeţeno je primjenom ekstrakata na sjeme, slijedi
primjena na list (prskanjem) pa primjena na korijen (zalijevanjem) test-vrste. Stimulativno
djelovanje nije utvrĎeno ni u jednom dijelu istraţivanja. Bez obzira na način primjene,
najjača djelovanja utvrĎena su ekstraktima korijena pajasena u kojem je najveća
koncentracija potentnih alelokemikalija. Tekućinskom kromatografijom utvrĎeno je da je
koncentracija ailantona, literaturno najpotentnije alelokemikalije pajasena, najveća u
ekstraktima korijena i iznosi 0,35 mg/ml. Koncentracija ailantona u ekstraktu stabljike
iznosi puno manjih 0,15 mg/ml, a u ekstraktu lista 0,12 mg/ml. Koncentracija ailantona u
ekstraktu čitave biljke je u skladu s utvrĎenim vrijednostima po pojedinim organima
pajasena i iznosi 0,19 mg/ml. UtvrĎeno je da djelovanje ailantona potpomaţu druge
alelokemikalije sadrţane u tkivima pajasena. |
| Abstract (english) | At the global level, the invasion of alien organisms represent the second largest threat to
biodiversity. The assumption is that the high allelopathic potential is one of the features
that helps invasive plant species to spread to new areas. The high level of aggressiveness
in most species is supported by the action of specific chemical compounds -
allelochemicals. Allelochemicals are secondary metabolites of plant metabolism that
determine relationships between individuals of the species called allelopathy. Many
allelochemicals act as "chemical weapon" and can potentially be used as natural
herbicides, growth regulators or as a base for their synthesis. Applying allelopathy in
agriculture can reduce the use of synthetic pesticides.
The study was divided into two parts. In the first part of the research, preliminary
identification of allelopathic potential of eight invasive non-native plant species (donor
species), from six different plant families, was determined. Donor species were Abutilon
theophrasti Med. - velvetleaf (family Malvaceae), Ambrosia artemisiifolia L. - ragweed
(Asteraceae), Datura stramonium L. – white jimsonweed (Solanaceae), Xanthium
strumarium L. - cocklebur (Asteraceae), Ailanthus altissima (Mill.) Swingle – tree of
heaven (Simaroubaceae), Amorpha fruticosa L. - indigo bush (Fabaceae), Reynoutria
japonica Houtte. - Japanese knotweed (Polygonaceae), Solidago gigantea Aiton - giant
goldenrod (Asteraceae). Three cultivated plant species from three different plant families
were used as test species: Avena sativa L. - oats (Poaceae), Brassica napus L. - oilseed
rape (Brassicaceae) and Helianthus annuus L. - sunflower (Asteraceae). Aqueous
extracts of eight donor species were applied to the seeds of the test-plants. Aqueous
extracts were made of whole plants. High allelopathic potential of all species included in
investigation was proven. Allelopathic effects are exclusively negative (inhibiting) and
intensity depending on the type of donor species and test-species. Allelopathic impact on
the percentage of germination in all species is much smaller in relation to the impact on
the radicle and shoot length of the test-species. Inhibitory effect on germination was
determined only to the extract of tree of heaven applied to the oilseed rape seed.
Perennial species have a stronger allelopathic potential than annual species. Tree of
heaven is species with the strongest allelopathic potential followed by white jimsonweed,
indigo bush, giant goldenrod, ragweed, Japanese knotweed. The smallest allelopathic
potential was determined in annual species velvetleaf and cocklebur. The most sensitive
test-plant is oilseed rape followed by oats and sunflower. Tree of heaven aqueous extract
inhibited radicle length of rapeseed 94.88%, and the length of sprouts 98.91%, which is
almost herbicidal activity of extracts. Tree of heaven and oilseed rape are therefore
included in the second part of the research in which aqueous extracts are made
separately from the roots, stems, leaves and whole plant of tree of heaven. Each of the
extracts was used in three different concentrations (total of 12 extracts) and applied to the
seed, root and leaf of the oilseed rape. Application to the seeds implies wetting the filter
paper in Petri dishes, application of the root implies watering in two different rates and
application on leaves implies spray application on previously raised test plants in 2 leaf
stage (BBCH 12). Inhibitory allelopathic effects of different intensities were observed,
depending on the type and concentration of the extracts and on the method of application.
The strongest effect was observed applying the extracts on the seeds, followed by
application on the leaves (spraying) and on the roots (watering) of the test-plants.
Stimulating effect was not found in any part of the research. Obtained results showed that
the tree of heaven contains allelochemicals in all investigated parts (root, stem, leaf).
Regardless of the method of application, the strongest effects were identified to the root
extracts of tree of heaven where is the highest concentration of potent allelochemicals.
Liquid chromatography determined that the concentration of ailanthone, in the literature
the most potent allelochemical of tree of heaven, is the largest in the root extracts (0,35
mg/ml), then extracts of the stem (0,15 mg/ml) and finally the leaf (0,12 mg/ml) extracts.
Concentration of ailanthone in whole plant extracts is in accordance with determined
values in individual organs of tree of heaven (0,19 mg/ml).
According to the obtained results, it can be concluded that tree of heaven contains
allelochemicals in all investigated parts. The largest source of potent allelochemicals is
the root. Action of ailanthon, as the most potent allelochemical, is supported by other
allelochemicals located in plant tissues of tree of heaven. The strongest effects were
determined by applying extracts on the seeds, then applying on the leaf, and the lowest by
applying on the root of the test-species. According to the determined test-species
reactions, there is a need for further similar studies, finding plants with high allelopathic
potential, identification and isolation of allelochemicals with the objective of their
application in crop production. Invasive plant species are a good option for further
allelopathy research. |
