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The consumption of fresh vegetables has been consistently associated with numerous health benefits. However, several factors (such as allelochemicals) influence yield, quality, and metabolites, which inevitably affect the fruit quality and health benefits. The present study was conducted to investigate the yield, quality, metabolic responses, and potential toxicity of Cucumis sativus grown in juglone-containing soils. For the treatments, pure juglone (100 µM, 1 mM) and walnut leaf extracts (100 µM) in soil concentrations found in walnut orchards were used. A total of 36 phenolic compounds were identified and quantified in fruits, leaves, and roots using a mass spectrometer coupled with high-performance liquid chromatography. We concluded that juglone at a concentration of 100 µM or walnut leaf extract at the same juglone concentration does not affect the yield of C. sativus, while juglone at a concentration of 1 mM strongly affects it. In the case of juglone, juglone itself was found only in the roots of C. sativus, but not in the leaves or fruits, so C. sativus fruits are considered safe for cultivation in juglone-containing soils. However, this could prove problematic if the plants grown are tubers or root vegetables. The data suggest that juglone itself inhibits secondary metabolism in the plant, making it more susceptible to stress and pathogen attacks.

Medicinal and aromatic plants with allelopathic effect are a potential source of natural herbicides. The experiment was conducted in order to assess herbicidal potential of meadow sage (Salvia pratensis L.) on germination and growth of weed species velvetleaf (Abutilon theophrasti Med.) and common corn-cockle (Agrostemma githago L.). Water extracts from S. pratensis dry biomass in different concentrations were evaluated under controlled laboratory conditions in Petri dish bioassay. Herbicidal effect of S. pratensis extracts depended on the extract concentration and weed species. In general, higher concentrations of water extract showed greater negative effect on germination and growth parameters of weed seedlings. A. githago had greater sensitivity to S. pratensis extracts with reductions in germination and seedlings growth up to 100% in treatments with 7.5% and 10% extract concentrations. A. theophrasti germination was not affected by water extracts, however, substantial reductions of root and shoot length as well as fresh weight of seedlings were recorded. S. pratensis proved as promising plant species for further studies., Ljekovite i aromatične biljke s alelopatskim djelovanjem potencijalni su izvor prirodnih herbicida. Pokus je proveden kako bi se utvrdio herbicidni potencijal livadne kadulje (Salvia pratensis L.) na klijanje i rast korovnih vrsta Teofrastov mračnjak (Abutilon theophrasti Med.) i poljski kukolj (Agrostemma githago L.). Vodeni ekstrakti od suhe biomase S. pratensis u različitim koncentracijama procijenjeni su u kontroliranim laboratorijskim uvjetima u pokusu u Petrijevim zdjelicama. Herbicidni utjecaj ekstrakata S. pratensis ovisio je o koncentraciji ekstrakta i vrsti korova. Općenito, više koncentracije vodenog ekstrakta pokazale su veći negativan učinak na klijavost i parametre rasta klijanaca korova. Vrsta A. githago pokazala je veću osjetljivost na ekstrakte S. pratensis sa smanjenjem klijavosti i rasta klijanaca do 100 % u tretmanima s koncentracijama ekstrakta od 7,5 % i 10 %. Vodeni ekstrakti nisu imali utjecaja na klijavost A. theophrasti, ali je zabilježeno značajno smanjenje duljine korijena i izdanaka kao i svježe mase klijanaca. S. pratensis pokazala se kao perspektivna biljna vrsta za daljnja istraživanja.

Cilj istraživanja bio je utvrditi alelopatski potencijal lucerne (Medicago sativa L.) na klijavost sjemena i rast klijanaca rotkvice (Raphanus sativus L.), radiča (Cichorium intybus L. var. foliosum) i rajčice (Lycopersicon esculentum Mill.). Vodeni ekstrakti pripremljeni od suhe nadzemne mase lucerne u tri koncentracije (1 %, 2,5 % i 5 %) testirani su u laboratorijskim uvjetima. Alelopatski potencijal lucerne ovisio je o test vrsti, koncentraciji vodenog ekstrakta te mjerenom parametru. Najslabije djelovanje zabilježeno je na klijavost te rast klijanaca rajčice. Povećanjem koncentracije vodenog ekstrakta povećavao se i negativni alelopatski potencijal. Najmanji utjecaj vodenih ekstrakata zabilježen je na suhu masu klijanaca test vrsta., The aim of the study was to determine the allelopathic potential of alfalfa (Medicago sativa L.) on seed germination and seedling growth of radish (Raphanus sativus L.), radicchio (Cichorium intybus L. var. foliosum) and tomato (Lycopersicon esculentum Mill.). Water extracts prepared from dry alfalfa biomass in three concentrations (1%, 2.5% and 5%) were tested under laboratory conditions. The allelopathic potential of alfalfa depended on the test species, the water extract concentration, and the measured parameter. The weakest effect was recorded on germination and growth of tomato seedlings. As the concentration of the water extract increased, the negative allelopathic potential also increased. Dry weight of seedlings of test species was the least affected.

Alelopatija je pojav, ko rastline preko sproščenih alelokemikalij zavrejo rast bližnjih rastlin. Namen naše raziskave je bil preučiti alelopatski vpliv invazivnih dresnikov, japonskega dresnika (Fallopia japonica) in češkega dresnika (F. ×bohemica), na strukturne, biokemijske, molekulske in ultrastrukturne značilnosti korenin testne vrste vrtne redkvice (Raphanus sativus). Izvlečka iz korenik obeh dresnikov sta se med seboj razlikovala po vsebnosti resveratrola. Metanolni izvlečki so imeli močnejši alelopatski učinek na redkvice kot posamezne alelokemikalije. Kalitev semen in rast korenin 3 dni starih kalic redkvice so zavrli tudi vodni izvlečki. V koreninah se je še posebej povišala vsebnost celokupnega glutationa, askorbata in prolina, kar kaže na znake oksidativnega stresa. Spremenilo se je tudi izražanje nekaterih genov, ki so povezani z askorbatno-glutationskim ciklom ter s programirano celično smrtjo. Izvlečki so povišali tudi aktivnost kaspazam in metakaspazam podobnih proteaz ter porušili organizacijo celic v posameznih koreninskih tkivih. Številne celice iz zunanjih slojev koreninske čepice so propadle. Na ultrastrukturnem nivoju so bile v celicah koreninske čepice najbolj izrazite naslednje spremembe: odstop plazmaleme od celične stene, poškodbe mitohondrijev, spremembe endoplazemskega retikuluma in pojav okroglih, elektronsko gostih vključkov v citoplazmi. Tudi meristemske celice so bile spremenjene. Pri daljši izpostavitvi je imel najbolj zaviralen učinek 10 % izvleček češkega dresnika, ki je povzročil propad večine rastlin. Rast glavne korenine tretiranih redkvic je bila v prvi polovici poskusa močno zavrta, po 14 dneh so pri preživelih redkvicah korenine dosegle kontrolno raven, parametri oksidativnega stresa niso bili povišani. Alelopatija dresnikov ima zaviralni vpliv predvsem na rast kalic redkvice, v koreninskih celicah se sproži oksidativni stres, kar vodi do programirane celične smrti. Allelopathy is a phenomenon in which plants inhibit the growth of neighboring plants by releasing allelochemicals. The aim of our study was to investigate the allelopathic effect of invasive knotweeds, Japanese knotweed (Fallopia japonica) and Bohemian knotweed (F. ×bohemica) on morphological, biochemical, molecular, and ultrastructural characteristics of roots of the tested species garden radish (Raphanus sativus). Extracts from both knotweeds differed in the content of resveratrol. Methanol extracts had a stronger allelopathic effect on radish than individual allelochemicals. In addition, aqueous extracts inhibited seed germination and root growth of 3-day-old radish seedlings. In particular, the content of total glutathione, ascorbate, and proline increased in the roots, indicating signs of oxidative stress. The expression of some genes related to ascorbate-glutathione cycle and programmed cell death were also altered. The extracts also increased the activities of caspase- and metacaspase-like proteases. The cell organization in root tissues was altered. Many cells from the outermost layer of the root cap were destroyed. The most prominent changes at the ultrastructural level were found in the root cap cells: plasmalemma was detached from the cell wall, mitochondria were damaged, endoplasmic reticulum changed and spherical electron dense inclusions appeared in the cytoplasm. The meristem cells were also altered. In long-term exposure, the 10 % extract of Bohemian knotweed showed the strongest inhibitory potential, causing the destruction of almost all plants. The primary root growth of the treated radish was strongly inhibited in the first half, after 14 days the root of the surviving plants reached the control level, oxidative stress related parameters did not increase. Knotweed allelopathy showed an inhibitory effect mainly on the growth of radish seedlings, which induce oxidative stress in the roots, leading to programmed cell death.

Kukuruzna silaža predstavlja značajnu sirovinu za proizvodnju bioplina. U usjevu silažnog kukuruza korovi su ograničavajući čimbenik uzgoja, a suzbijanje korova osnovna agrotehnička mjera koja se uglavnom provodi primjenom herbicida. Međutim, cilj EU strategije „Zeleni plan“ je do 2030. godine smanjiti korištenja pesticida za 50%. Stoga su nužno potrebne alternativne metode suzbijanja korova. Fenolne kiseline imaju potencijal inhibicije rasta korova pa se istražuje mogućnost njihove primjene sa značajno reduciranim dozacijama herbicida. Cilj istraživanja je utvrditi selektivnost kukuruza prema kombinaciji reducirane doze herbicida i fenolne kiseline. U laboratorijskom dijelu istraživanja sjeme kukuruza tretirano je punom (x) i reduciranim dozama herbicida Adenga (1/2, ¼, 1/8, 1/16 x) i s feruličnom/p-hidroksibenzojevom kiselinom dodanim istim dozacijama herbicida. Navedeni dio prethodio je biotestu u klima komori u kojem je kukuruz tretiran istim dozacijama herbicida samostalno i u kombinaciji s feruličnom kiselinom. Iako su u laboratorijskom dijelu fenolne kiseline pojačale redukcijski učinak herbicida Adenga na klijavost i rani rast kukuruza, vizualnom ocjenom oštećenja nadzemne mase nisu utvrđena značajna oštećenja mladih biljaka kukuruza. Maize silage is an important raw material for biogas production. In silage maize cultivation, weeds are the limiting factor, and weed control is a basic agrotechnical measure, mainly through the use of herbicides. However, the goal of the EU Green Plan strategy is to reduce the use of pesticides by 50% by 2030. Therefore, alternative methods of weed control are needed. Phenolic acids have the potential to inhibit the growth of weeds. Therefore, the possibility of their application with significantly reduced herbicide doses is being investigated. The aim of the research is to determine the selectivity of maize to the combination of reduced doses of herbicide and phenolic acid. In the laboratory part of the study, maize seeds were treated with full (x) and reduced doses of the herbicide Adenga (1/2, ¼, 1/8, 1/16 x) and with ferulic acid/p-hydroxybenzoic acid added to the same herbicide doses. The mentioned part preceded the bioassay in the climate chamber, where maize was treated with the same herbicide doses alone and in combination with ferulic acid. Although in the laboratory part the phenolic acids enhanced the reducing effect of the herbicide Adengo on the germination and early growth of maize, the visual assessment of the injury to the aboveground mass did not reveal any significant damage to young maize plants.

V zadnjem času vse več raziskav poteka v smeri koristne uporabe invazivnih tujerodnih rastlinskih vrst. V magistrski nalogi nas je zanimalo, ali bi lahko njihove ekstrakte uporabili za zatiranje semen trpežne ljuljke (Lolium perenne). V laboratorijskem poskusu smo preučevali, ali ekstrakti nadzemnih delov dresnika (Fallopia sp.), navadne barvilnice (Phytolacca americana), octovca (Rhus typhina) in žlezave nedotike (Impatiens glandulifera) kakor koli vplivajo na kalitev trpežne ljuljke. Poleg tega smo s pomočjo HPLC analizirali, katere fenolne spojine so prisotne v teh vrstah ter ugotavljali, kako čas ekstrakcije vpliva na vsebnost teh snovi v njihovih izvlečkih. Iz rezultatov poskusa smo ugotovili, da je imel izvleček dresnika, navadne barvilnice in octovca zaviralen vpliv na kalitev semen ter na rast korenine in poganjka trpežne ljuljke. Izvleček žlezave nedotike je imel zaviralen vpliv le na kalitev semen in na rast poganjka trpežne ljuljke. Ekstrakcija z metanolnim topilom se je izkazala za bolj učinkovit način ekstrakcije v primerjavi z ekstrakcijo z vodnim topilom fenolnih spojin iz teh rastlin. Daljši čas ekstrakcije je značilno vplival na večjo vsebnost hidroksicimetnih in hidroksibenzojskih kislin v izvlečku octovca, na vsebnost flavanolov v izvlečku dresnika, navadne barvilnice in octovca ter na vsebnost flavonolov v izvlečku octovca in žlezave nedotike. Recently, a lot of studies have been done on the beneficial uses of invasive alien plant species (IAPS). In our master's thesis, we were interested in whether IAPS extracts could be used to control the seeds of the perennial ryegrass (Lolium perenne). In a laboratory experiment, we investigated whether extracts from the non-root plant parts of knotweed (Fallopia sp.), American pokeweed (Phytolacca americana), staghorn sumac (Rhus typhina), and Himalayan balsam (Impatiens glandulifera) in any way affect the germination of perennial ryegrass. In addition, HPLC was used to analyze which phenolic compounds are present in studied species and how the time of extraction affects the content of these compounds in the extracts. From the experimental results, the extracts of knotweed, American pokeweed, and staghorn sumac inhibit seed germination and growth of the root and shoot of perennial ryegrass. Himalayan balsam extract had an inhibitory effect on seed germination and perennial ryegrass shoot growth. Extraction with methanol proved to be an efficient way to extract phenolic compounds from these plants. Longer extraction time significantly affected the content of hydroxycinnamic acids and hydroxybenzoic acids in staghorn sumac extract, the content of flavanols in the extract of knotweed, American pokeweed, and staghorn sumac, and the content of flavonols in the extract of staghorn sumac and Himalayan balsam.

Cilj ovog rada bio je ispitati učinak metanolnog ekstrakta žljezdastog nedirka (Impatiens glandulifera R., Balsaminaceae) na klijavost sjemenki i na razinu oksidacijskog stresa u klijanaca rotkvice (Raphanus sativus L., Brassicaceae). Sjemenke vrste R. sativus tri su dana bile izložene metanolnom ekstraktu lista vrste I. glandulifera kojim se impregnirao filtar papir trima različitim dozama (1,5 ml; 3,0 ml i 6,0 ml). Za pozitivnu kontrolu filtar papir je impregniran s 0,02 M otopinom CuSO4, a negativna kontrola bio je tretman deioniziranom vodom. Modelni organizam (R. sativus) tretiran je u triplikatu. Nakon trodnevne izloženosti, izvagana je masa svježeg tkiva klijanaca rotkvice te je potom pripremljen homogenat biljnog tkiva u trikloroctenoj kiselini (100 mg tkiva/0,5 mL TCA). U supernatantu homogenata određeni su parametri oksidacijskog stresa: sadržaj reduciranog glutationa (GSH), antocijanina, malondialdehida (MDA) i oksidiranih proteina. Metodom prema Ellmanu (1959) određen je sadržaj GSH, antocijanini su pH-diferencijalnom metodom mjereni prema Giusti i Wrolstadu (2001), tiobarbituratnim testom prema Heathu i Packeru (1968) određen je MDA, a derivatizacijom karbonilne skupine proteina s DNPH prema Levine i sur. (1990) određen je sadržaj oksidiranih proteina. Rezultati su statistički obrađeni t-testom (program Excel, P < 0,05). Masa svježeg tkiva klijanaca rotkvice tretiranih ekstraktom žljezdastog nedirka bila je niža u odnosu na negativnu kontrolu. Značajnija promjena u sadržaju neenzimskih antioksidansa, GSH i antocijanina u odnosu na negativnu kontrolu nije zabilježena. Sadržaj MDA u klijanaca rotkvice tretiranih s najvišom dozom (6,0 ml) ekstrakta bio je viši u usporedbi s negativnom kontrolom. Sadržaj oksidiranih proteina klijanaca tretiranih s ekstraktom žljezdastog nedirka bio je viši od negativne kontrole, a statistički značajno viši bio je nakon tretmana s najvišom dozom ekstrakta, 6,0 ml (negativna kontrola vs. najviša doza ekstrakta; 7,553 ± 0,906 μM vs. 9,720 ± 0,548 μM, P = 0,012). Prema dobivenim rezultatima može se zaključiti kako ekstrakt biljne vrste I. glandulifera fitotoksično djeluje na klijanje vrste R. sativus, ali se u modelnoj biljci, u eksperimentalnim uvjetima, nije aktivirao adekvatan odgovor na oksidacijski stres (porast sadržaja GSH i antocijanina). To je rezultiralo porastom sadržaja MDA i oksidiranih proteina, odnosno došlo je do oksidacijskog stresa. Dobiveni rezultati jasno pokazuju da je oksidacijski stres mehanizam alelopatskog djelovanja biljne vrste I. glandulifera. The aim of this study was to explore the effect of methanol extract of himalayan balsam (Impatiens glandulifera R., Balsaminaceae) on seed germination and on the level of oxidative stress in radish seedlings (Raphanus sativus L., Brassicaceae). Seeds of R. sativus were treated for three days with methanol extract prepared from I. glandulifera leaves (filter papers were impregnated with three doses of methanol extract: 1.5, 3 and 6 mL). As positive control 0.02 M CuSO4 solution was used, and negative control was treatment with deionized water. The model organism (R. sativus) was treated in triplicate. After three days of exposure, the fresh mass of radish seedlings was weighed. Plant tissue homogenate was prepared using trichloroacetic acid (100 mg tissue/0.5 mL TCA). As parameters of oxidative stress, the content of reduced glutathione (GSH), anthocyanin, malondialdehyde (MDA) and oxidized proteins was determined in the supernatant of the homogenates. The GSH content was determined using the Ellman method (1959), anthocyanins were measured by the pH-differential method according to Giusti and Wrolstad (2001), the MDA was determined by using the thiobarbituric test according to Heath and Packer (1968) and the content of oxidized proteins was determined by derivatization of the carbonyl group of proteins with DNPH according to Levine et al. (1990). The obtained results were statistically analysed (t-test, Excel; P

U ovom istraživanju ispitan je oksidacijski stres kao mehanizam alelopatskog djelovanja žljezdastog nedirka (Impatiens glandulifera Royle, Balsaminaceae). Razina oksidacijskog stresa praćena je mjerenjem aktivnosti antioksidacijskog enzima superoksid dismutaze (SOD) u klijanaca bijele gorušice (Sinapis alba L., Brassicaceae) i rotkvice (Raphanus sativus L., Brassicaceae) nakon izloženosti ekstraktu žljezdastog nedirka. Sjemenke bijele gorušice i rotkvice bile su izložene 3 dana metanolnom ekstraktu žljezdastog nedirka u tri doze (1,5; 3 i 6 ml). U pokus je bila uključena pozitivna kontrola (PK, tretman s 0,02 M CuSO4) te negativna kontrola (NK, tretman destiliranom vodom). Svi tretmani provedeni su u triplikatu. Nakon 3-dnevnog klijanja, pripremljen je homogenat biljnoga tkiva, a u supernatantu homogenata izmjerena je aktivnost antioksidacijskog enzima SOD pomoću komercijalnog kita kolorimetrijskom metodom. Prije samog mjerenja aktivnosti SOD u uzorcima, metoda je optimizirana ispitivanjem njene linearnosti i načina pripreme uzorka. Dobiveni rezultati aktivnosti SOD obrađeni su statistički (t-test, Excel; P ≤ 0,05). Utvrđeno je da je metode za određivanje aktivnosti SOD linearna (koeficijent linearnosti, R2 = 0,9406) s jednadžbom pravca y = 69,302x + 1,1463. Za određivanje aktivnosti SOD u homogenatu biljnoga tkiva optimalnim se pokazalo razrijeđenje supernatanta homogenata uzorka 2x s pojačivačem za uzorke. U klijanaca bijele gorušice nakon 3-dnevnog tretmana s 1,5 ml ekstrakta žljezdastog nedirka aktivnost SOD značajno je pala (52%) u odnosu na NK (100 %, P ≤ 0,05). S povećanjem doze ekstrakta, u klijanaca bijele gorušice zabilježen je porast aktivnosti SOD (3 ml: 73 %, 6 ml: 80 %). U klijanaca rotkvice 3-dnevni tretmana s ekstraktom žljezdastog nedirka uzrokovao je postepeni pad aktivnosti SOD te je u odnosu na NK (100 %) najniža aktivnost SOD (86 %) bila nakon tretmana s 3 ml ekstrakta. Porast aktivnosti SOD nakon 3-dnevnog tretmana s višim dozama ekstrakta žljezdastog nedirka (3 ml i 6 ml zabilježen u klijanaca bijele gorušice i 6 ml zabilježen u klijanaca rotkvice) može se objasniti odgovorom biljke na vanjski utjecaj, odnosno povećanoj sintezi enzima SOD kao odgovor na stres. S obzirom da je značajniji pad aktivnosti SOD zabilježen u klijanaca bijele gorušice u odnosu na klijance rotkvice može se zaključiti da rotkvica ima razvijeniji antioksidacijski sustav. Dobiveni rezultati pokazuju da je oksidacijski stres mehanizam alelopatskog djelovanja žljezdastog nedirka. In this research, oxidative stress, as an allelopathic mechanism of himalayan balsam (Impatiens glandulifera Royle, Balsaminaceae) was examined. The level of oxidative stress was monitored by measuring the activity of antioxidative enzyme superoxide dismutase (SOD) in seedlings of white mustard (Sinapis alba L., Brassicaceae) and radish (Raphanus sativus L., Brassicaceae) exposed to the extract of himalayan balsam. Seeds from both plants, white mustard and radish, were exposed to a methanol extract of himalayan balsam in three doses (1.5, 3 and 6 mL). In experiment, positive control (PC, treatment with 0.02 M CuSO4) and negative control (NC, treatment with destiled water) were also included. All treatments were done in a triplicate. After 3 days of treatment, plant tissue homogenate was prepared and in its supernatant SOD activity was determined via comercial assay kit based on colorimetry. Before determining SOD activity in seedlings, the method was optimised by testing its linearity and sample preparation procedure. Obtained data on SOD activity was processed statisticaly (t-test, Excel; P ≤ 0.05). The method for assessment SOD activity was linear (R2 = 0.9406; y = 69,302x + 1,1463). Several sample dilutions were tested, and the optimal was dilution of samples 2x with sample buffer. In seedlings of white mustard after 3-days exposure to 1.5 mL of methanol extract of himalayan balsam SOD activity significantly decreased in comparison to NC (52% vs. 100%, P ≤ 0.05). With the increase of the dose of the extract in seedlings of white mustard an increase of SOD activity was recorded (3 mL: 73 %, 6 mL: 80 %). In radish seedlings 3-days exposure to methanol extract of himalayan balsam resulted with slow decrease of SOD activity and the lowest SOD activity in comparison to NC was after exposure to 3 mL of extract (86 % vs. 100 %). An increase of SOD activity after exposure to higher doses of extract of himalayan balsam (3 mL and 6 mL for white mustard and 6 mL for radish) can be explained with the synthesis of SOD as a response of seedlings to stress. Since significant decrease of SOD activity was observed in sedlings of white mustard in comparison to seedlings of radish, can be concluded that seedlings of radish has better antioxidative defence system. The obtained results indicate that oxidative stress is the mechanism of himalayan balsam allelopathy.

Z naselitvami invazivnih tujerodnih vrst v nova okolja se dogajajo težko popravljive spremembe v ekosistemih in naravnih habitatih. Biodiverzitetna kriza je izrazit upad biotske pestrosti, ki je posledica različnih in hkratnih človekovih vplivov. Invazivne tujerodne rastlinske vrste so tiste, ki prav tako povzročajo spremembe v okolju in lahko negativno vplivajo na ekosisteme, avtohtone združbe, zdravje ljudi in gospodarstvo. Invazivne rastlinske vrste so v globalnem merilu eden izmed glavnih vzrokov upadanja biotske pestrosti in izumiranja vrst. V nalogi sem se osredotočila na to, kakšni tekmovalci so z avtohtonimi rastlinami ter zakaj imajo prednost v širjenju in uspevanju v novih okoljih. Invazivne tujerodne rastline so uspešne zaradi svojih ekološko-bioloških značilnosti, kot so hitra rast in produkcija velikega števila semen, poznejše cvetenje in mnogo drugih. V novem okolju invazivne tujerodne rastline tekmujejo z avtohtonimi za življenjski prostor, vodo, hranila in druge življenjsko pomembne vire. S svojimi mehanizmi delovanja škodijo biotski pestrosti preko kompeticijskih razmerij in spreminjanjem habitatov različnim vrstam v združbi, alelopatije, križanja z avtohtonimi vrstami in povzročanjem genskega onesnaženja ter uspešnim izkoriščanjem virov in učinkovitim prilagajanjem na spremembe v okolju. Pregledane objave dokazujejo, da so invazivne rastline ena izmed groženj biotski pestrosti, zato je pomembno razumevanje njihovega širjenja in učinkovanja v združbi, predvsem pa ukrepanje na ravni preprečevanja vnosov v novo okolje ter zatiranja v primeru razširitve. With the settlement of invasive alien species in new environments, irreversible changes in ecosystems and natural habitats are happening. The biodiversity crisis is a great decline in biodiversity, which is the result of human and other influences. Invasive alien plant species are those who cause changes in the environment and can negatively affect ecosystems, native communities, human health and the economy. Invasive plant species are one of the main causes of the decline in biodiversity and species extinction on a global scale. In this assignment I focused on what kind od competitors they are with native plants and why they have an advantage in spreading and thriving in new environments. Invasive plants are successful due to their ecological and biological characteristics, such as rapid growth and production of large number of seeds, later flowering and many others. In new environments invasive alien plant species compete with native ones for habitat, water, food and other vital resources. With their mechanisms of action, they harm biodiversity through competitive relationships and species habitat changes, allelopathy, crossbreeding with native species and good resource utilization and effective adaptation to environmental changes. Rewieved literature suggests that invasive plants are certainly a threat to biodiversity, so understanding their spreading and functioning in communities is important, as well as how to take action in preventing the event of introduction into a new enviornment and suppressing spreading in the event of enlargement.

Cilj istraživanja bio je utvrditi utjecaj vodnog stresa odnosno različitih normi navodnjavanja na alelopatski potencijal salate (Lactuca sativa L.). Pokus je proveden u Petrijevim zdjelicama prema potpuno slučajnom planu s tretmanima u šest ponavljanja u kontroliranim laboratorijskim uvjetima. Alelopatski potencijal vodenih ekstrakata pripremljenih od listova salate uzgajane pri različitim normama navodnjavanja (45 mm, 90 mm i 135 mm) testiran je u tri koncentracije (2, 5 %, 5 % i 10 %) na klijavost sjemena i rast klijanaca rotkvice. Alelopatski utjecaj procijenjen je mjerenjem klijavosti sjemena, duljine korijena i izdanka, te svježe mase klijanaca rotkvice. Alelopatski potencijal vodenih esktrakata salate ovisio je o normi navodnjavanja i koncentraciji. Povećanjem koncentracije vodenih ekstrakata povećavao se negativni alelopatski utjecaj, te je zabilježeno potpuno inhbitorno djelovanje (100 %) na klijavost i rast klijanaca rotkvice u tretmanima s ekstraktima najviše koncentracije. Vodni stres uzrokovao je veći negativni alelopatski potencijal. Vodeni ekstrakti koncentracije 5 % pripremljeni od salate uzgajane pri dvije niže norme navodnjavanja od 45 mm i 90 mm imali statistički značajno jače inhibitorno djelovanje od ekstrakata salate uzgajane pri normi navodnjavanja od 135 mm na sve mjerene parametre.