The present master's thesis has the purpose of studying, through ex situ cultivation and laboratory’s experiments, the vegetative reproduction’s capacity and the desiccation resistance of Wolffia columbiana H.Karst. (Araceae, Lemnoideae), an American hydrophyte naturalized in Italy, with the aim to examine its dispersion modalities and its potential invasiveness in the introduction area. The plant material was sampled in the only known growing site in Italy, a small pond along the Po river located in the village of Pieve Porto Morone (Lombardy, Pavia). Live plants were collected between spring 2017 and spring 2018 and were grown at the Botanical Garden of the University of Pavia. The laboratory tests were carried out at the Plant Germplasm Bank of the University of Pavia, testing different temperature ranges (from 5° C to 45° C) and different photoperiod intervals (15 h, 20 h, 12 h) which they simulated temperature and photoperiod’s conditions throughout the European and Mediterranean area. To test the desiccation resistance, a total time interval of seven hours was considered. The reaction of the plant to the different conditions of temperature, photoperiod and desiccation was measured through the vegetative multiplication capacity. The test’s results, analyzed statistically through a generalized linear model (GLM), showed that temperature has a significant effect on the multiplication of this plant. Particularly, it has been seen that, in the temperature range between 20° C and 35° C, there is the multiplication peak of W. columbiana. The photoperiod, on the other hand, has no significant effect. The results of the test on resistance to desiccation showed that desiccation negatively affects the plant after four hours outside the aquatic environment. In fact, after this time interval, a decrease in the multiplication capacity of the plant was observed. The results obtained demonstrate how this W. columbiana, native to the temperate and tropical areas of northern and southern America, is potentially invasive at the latitudes of the study area (Italy and southern Europe), being its morphological features and its ecological needs compatible with a possible long-distance dispersion mediated by birds.
La presente tesi di Laurea Magistrale ha avuto lo scopo di studiare, attraverso esperimenti di coltivazione ex situ e in laboratorio, la capacità di riproduzione vegetativa e la resistenza al disseccamento di Wolffia columbiana H.Karst. (Araceae, Lemnoideae), idrofita americana naturalizzata in Italia, nell’ottica di approfondire le sue modalità di dispersione e la sua potenziale invasività nell’areale d’introduzione. Il materiale vegetale è stato campionato nell’unica stazione nota in Italia, una lanca lungo il corso del Fiume Po, situata nel comune di Pieve Porto Morone (Pavia). Piante vive sono state raccolte tra la primavera del 2017 e la primavera del 2018 e sono state coltivate presso l’Orto Botanico dell’Università di Pavia. Le prove di laboratorio sono state condotte presso la Banca del Germoplasma Vegetale dell’Università di Pavia, testando diversi intervalli di temperature (da 5° C a 45° C) e diversi intervalli di fotoperiodo (15 h, 20 h, 12 h) che hanno simulato le condizioni di temperatura e di fotoperiodo in tutta la zona europea e mediterranea. Per testare la resistenza al disseccamento si è preso in considerazione un intervallo di tempo complessivo di sette ore. La reazione della pianta alle diverse condizioni di temperatura, fotoperiodo e disseccamento è stata misurata attraverso la capacità di moltiplicazione vegetativa. I risultati dei test, analizzati statisticamente tramite un modello lineare generalizzato (GLM), hanno evidenziato come la temperatura abbia un effetto significativo sulla moltiplicazione di questa pianta. In particolare, si è visto che, nell’intervallo di temperatura compreso tra 20° C e 35° C, si ha il picco della moltiplicazione di W. columbiana. Il fotoperiodo, invece, non ha alcun effetto significativo. I risultati del test sulla resistenza al disseccamento hanno evidenziato come esso incida negativamente sulla pianta dopo quattro ore fuori dall’ambiente acquatico. Infatti, trascorso questo intervallo di tempo, si è osservato un decremento della capacità di moltiplicazione della pianta. I risultati ottenuti dimostrano come W. columbiana, originaria delle zone temperate e tropicali dell’America settentrionale e meridionale, risulti potenzialmente invasiva alle latitudini dell’areale di studio (Italia ed Europa meridionale), essendo le sue caratteristiche morfologiche e le sue esigenze ecologiche compatibili con una possibile dispersione su lunga distanza mediata dagli uccelli.
Riproduzione vegetativa e resistenza al disseccamento di Wolffia columbiana H.Karst. (Araceae), idrofita alloctona naturalizzata in Italia.
MANISCO, MARTA ILARIA
2018/2019
Abstract
The present master's thesis has the purpose of studying, through ex situ cultivation and laboratory’s experiments, the vegetative reproduction’s capacity and the desiccation resistance of Wolffia columbiana H.Karst. (Araceae, Lemnoideae), an American hydrophyte naturalized in Italy, with the aim to examine its dispersion modalities and its potential invasiveness in the introduction area. The plant material was sampled in the only known growing site in Italy, a small pond along the Po river located in the village of Pieve Porto Morone (Lombardy, Pavia). Live plants were collected between spring 2017 and spring 2018 and were grown at the Botanical Garden of the University of Pavia. The laboratory tests were carried out at the Plant Germplasm Bank of the University of Pavia, testing different temperature ranges (from 5° C to 45° C) and different photoperiod intervals (15 h, 20 h, 12 h) which they simulated temperature and photoperiod’s conditions throughout the European and Mediterranean area. To test the desiccation resistance, a total time interval of seven hours was considered. The reaction of the plant to the different conditions of temperature, photoperiod and desiccation was measured through the vegetative multiplication capacity. The test’s results, analyzed statistically through a generalized linear model (GLM), showed that temperature has a significant effect on the multiplication of this plant. Particularly, it has been seen that, in the temperature range between 20° C and 35° C, there is the multiplication peak of W. columbiana. The photoperiod, on the other hand, has no significant effect. The results of the test on resistance to desiccation showed that desiccation negatively affects the plant after four hours outside the aquatic environment. In fact, after this time interval, a decrease in the multiplication capacity of the plant was observed. The results obtained demonstrate how this W. columbiana, native to the temperate and tropical areas of northern and southern America, is potentially invasive at the latitudes of the study area (Italy and southern Europe), being its morphological features and its ecological needs compatible with a possible long-distance dispersion mediated by birds.È consentito all'utente scaricare e condividere i documenti disponibili a testo pieno in UNITESI UNIPV nel rispetto della licenza Creative Commons del tipo CC BY NC ND.
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https://hdl.handle.net/20.500.14239/17593