The main objective of this study was to observe the effects of some biostimulants with foliar application in the model species Arabidopsis thaliana and in Vitis vinifera, variety Sauvignon-Blanc and Glera. The scheme developed for water stress tolerance analysis was calibrated on A. thaliana and then adapted for subsequent experimentation on grapevine. The experiment on the model species was conducted in the growth chamber and involved the use of 5 different foliar treatments based on inactivated yeast derivative formulations. Water stress was induced using the gravimetric method, maintaining the water content of the growth medium at the target of 30 percent of its field capacity (CC). Control theses, on the other hand, were maintained above 80% of CC. Physiological responses of the plants were monitored by measurement of stomatal conductance (gs). Growth activity was quantified with the Phenotiki phenotyping platform. Potential oxidative damage to leaves was determined by determination of hydrogen peroxide distribution. Finally, an evaluation of gene expression of RAB18, a known gene whose activity correlates with abiotic stresses, was conducted. As for the experiment on grapevine, conducted in the az. Agraria Lucio Toniolo, a number of 160 potted vines were placed in semi-controlled conditions (tunnel) and grown vertically with only two shoots. The vines were divided into 4 theses using a randomized 4-block scheme and treated with two biostimulant products supplied by the company Lallemand, LalvigneTM Resiliens and LalvigneTM ProHydro. The other two theses consisted of the combined treatment of the two products mentioned before and an untreated control. After budding, vine growth was monitored by weekly measurements of shoot length and leaf area. In pre-sprouting, on the other hand, a controlled water stress experiment was set up: for each thesis, 4 blocks of 5 vines were subjected to conditions of gradual reduction of substrate water content starting from the control condition (WW) above 80% CC to 30% CC. Physiological responses in response to water stress were evaluated by measuring stomatal conductance and leaf water potential. At harvest stages, the potential impact of products on berry quality was investigated by determining sugar content (°Brix) and titratable acidity. The analyses were completed with berry unit weight, bunch weight and number of berries produced by the thesis being compared, for feedback on fruit set percentage. In both case studies, measurements were taken before, during and after (recovery) the induction of water stress. In the open field case study, the performance of theses treated exclusively with the product LalvigneTM ProHydro was evaluated. With regard to water potential, both midday and stem potential could be evaluated, and monitoring of leaf pigments (total chlorophylls, flavonols, anthocyanins) and leaf NBI index was performed. From the results obtained, there was evidence of how water stress affects plant growth parameters and how, in some cases, products can help to partially mitigate its negative effects. Encouraging results, on the other hand, have emerged on stimulating leaf area development, performance in the stages following the recovery period, and balancing the sugar content and titratable acidity of treated plants. However, new investigations need to be carried out, trying to limit environmental variability, which often greatly affected the statistical analyses conducted.
Questo studio ha avuto come principale obiettivo l’osservazione degli effetti di alcuni biostimolanti ad applicazione fogliare nella specie modello Arabidopsis thaliana ed in Vitis vinifera, varietà Sauvignon-Blanc e Glera. Lo schema messo a punto per le analisi sulla tolleranza allo stress idrico è stato calibrato su A. thaliana e poi adattato per la successiva sperimentazione su vite. L’esperimento sulla specie modello è stato condotto in camera di crescita ed ha previsto l’uso di 5 differenti trattamenti fogliari a base di formulati di derivati di lieviti inattivati. Lo stress idrico è stato indotto utilizzando il metodo gravimetrico, mantenendo il contenuto idrico del substrato di crescita al target del 30% della sua capacità di campo (CC). Le tesi di controllo, invece sono state mantenute al di sopra del’80% della CC. Le risposte fisiologiche delle piante sono state monitorate tramite misurazione della conduttanza stomatica (gs). L’attività di crescita è stata quantificata con la piattaforma di fenotipizzazione Phenotiki. I potenziali danni ossidativi a carico delle foglie sono stati determinati tramite la determinazione della distribuzione del perossido di idrogeno. Infine, è stata condotta una valutazione dell’espressione genica di RAB18, un gene conosciuto la cui attività è correlata agi stress abiotici. Per quanto riguarda l’esperimento su vite, condotto nell’az. Agraria Lucio Toniolo, un numero di 160 viti in vaso sono state poste in condizioni semi-controllate (tunnel) e cresciute verticalmente con due soli germogli. Le viti sono state suddivise in 4 tesi, utilizzando uno schema a 4 blocchi randomizzati e trattate con due prodotti biostimolanti forniti dalla ditta Lallemand, LalvigneTM Resiliens e LalvigneTM ProHydro. Le altre due tesi sono state composte dal trattamento combinato dei due prodotti prima menzionati e da un controllo non trattato. Dopo il germogliamento, la crescita delle viti è stata monitorata mediante misure settimanali della lunghezza dei germogli e dell’area fogliare. In pre-invaiatura, invece, è stato impostato un esperimento di stress idrico controllato: per ogni tesi, 4 blocchi da 5 viti sono state sottoposte a condizioni di graduale riduzione del contenuto idrico del substrato a partire dalla condizione di controllo (WW) superiore all’80% della CC fino al 30% della CC. Le risposte fisiologiche in risposta allo stress idrico sono state valutate mediante misurazione della conduttanza stomatica e del potenziale idrico fogliare. Nelle fasi della vendemmia, è stato indagato il potenziale impatto dei prodotti sulla qualità delle bacche, determinando il contenuto zuccherino (°Brix) e l’acidità titolabile. Le analisi si sono completate con il peso unitario bacca, il peso dei grappoli ed il numero delle bacche prodotte dalla tesi a confronto, per un riscontro sulla percentuale di allegagione. Nel caso studio di pieno campo, sono state valutate le performance delle tesi trattate esclusivamente con il prodotto LalvigneTM ProHydro. Per quanto concerne il potenziale idrico, è stato possibile valutare sia il potenziale di midday che dello stem, ed è stato eseguito il monitoraggio dei pigmenti fogliari (clorofille totali, flavonoli, antocianine) e dell’indice fogliare NBI. Dai risultati ottenuti, si è avuto riscontro di come lo stress idrico incida sui parametri di accrescimento delle piante e di come, in certi casi, i prodotti possano contribuire a mitigarne parzialmente gli effetti negativi. Risultati incoraggianti sono invece emersi sullo stimolo allo sviluppo dell’area fogliare, sulle prestazioni nelle fasi successive al periodo di recovery e sul bilanciamento del tenore di zuccheri e dell’acidità titolabile delle piante trattate. Tuttavia, è necessario effettuare nuove indagini, cercando di limitare la variabilità ambientale, che spesso ha inciso fortemente sulle analisi statistiche
Effetti dell'applicazione di biostimolanti fogliari sulla tolleranza allo stress idrico in Arabidopsis thaliana e Vitis vinifera cv. Sauvignon Blanc
BALSAMO, PIERLUCA
2021/2022
Abstract
The main objective of this study was to observe the effects of some biostimulants with foliar application in the model species Arabidopsis thaliana and in Vitis vinifera, variety Sauvignon-Blanc and Glera. The scheme developed for water stress tolerance analysis was calibrated on A. thaliana and then adapted for subsequent experimentation on grapevine. The experiment on the model species was conducted in the growth chamber and involved the use of 5 different foliar treatments based on inactivated yeast derivative formulations. Water stress was induced using the gravimetric method, maintaining the water content of the growth medium at the target of 30 percent of its field capacity (CC). Control theses, on the other hand, were maintained above 80% of CC. Physiological responses of the plants were monitored by measurement of stomatal conductance (gs). Growth activity was quantified with the Phenotiki phenotyping platform. Potential oxidative damage to leaves was determined by determination of hydrogen peroxide distribution. Finally, an evaluation of gene expression of RAB18, a known gene whose activity correlates with abiotic stresses, was conducted. As for the experiment on grapevine, conducted in the az. Agraria Lucio Toniolo, a number of 160 potted vines were placed in semi-controlled conditions (tunnel) and grown vertically with only two shoots. The vines were divided into 4 theses using a randomized 4-block scheme and treated with two biostimulant products supplied by the company Lallemand, LalvigneTM Resiliens and LalvigneTM ProHydro. The other two theses consisted of the combined treatment of the two products mentioned before and an untreated control. After budding, vine growth was monitored by weekly measurements of shoot length and leaf area. In pre-sprouting, on the other hand, a controlled water stress experiment was set up: for each thesis, 4 blocks of 5 vines were subjected to conditions of gradual reduction of substrate water content starting from the control condition (WW) above 80% CC to 30% CC. Physiological responses in response to water stress were evaluated by measuring stomatal conductance and leaf water potential. At harvest stages, the potential impact of products on berry quality was investigated by determining sugar content (°Brix) and titratable acidity. The analyses were completed with berry unit weight, bunch weight and number of berries produced by the thesis being compared, for feedback on fruit set percentage. In both case studies, measurements were taken before, during and after (recovery) the induction of water stress. In the open field case study, the performance of theses treated exclusively with the product LalvigneTM ProHydro was evaluated. With regard to water potential, both midday and stem potential could be evaluated, and monitoring of leaf pigments (total chlorophylls, flavonols, anthocyanins) and leaf NBI index was performed. From the results obtained, there was evidence of how water stress affects plant growth parameters and how, in some cases, products can help to partially mitigate its negative effects. Encouraging results, on the other hand, have emerged on stimulating leaf area development, performance in the stages following the recovery period, and balancing the sugar content and titratable acidity of treated plants. However, new investigations need to be carried out, trying to limit environmental variability, which often greatly affected the statistical analyses conducted.| File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/40181