1,721,257 research outputs found
Intervento di Trivellini. Impiego di protesi riassorbibili e non nel trattamento delle recidive erniarie e dei laparoceli con perdita di sostanza reale
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Combined use of resorbable and nonresorbable prostheses in the treatment of major defects of the abdominal wall
No full textAnalisi del trascrittoma durante lo sviluppo e la senescenza dei fiori di Hibiscus rosa-sinensis L.
No full textLa senescenza dei fiori è un processo programmato e altamente regolato a livello genetico. I tessuti fiorali durante la senescenza subiscono dei profondi cambiamenti che coinvolgono diversi processi fisiologici e biochimici. Per approfondire le basi genetiche che regolano questi processi è stato effettuato un’analisi del trascrittoma dei fiori di ibisco (Hibiscus rosa-sinensis L.). I fiori sono stati campionati allo stadio di gemma e fiore aperto/senescente al fine di ottenere il maggior numero di geni possibili coinvolto nel processo d’invecchiamento dei fiori. Dai campioni è stato estratto l’RNA totale e utilizzato per la costruzione di una libreria a doppia elica di cDNA. Le librerie sono state sequenziate utilizzando la tecnologia 454 al fine di ottenere sequenze lunghe da poter facilmente annotare. Il sequenziamento ha prodotto 30988 geni totali tra gemma e fiori aperti/senescenti. In particolare, nella gemma sono stati isolati 23058 geni e nei fiori aperti/senescenti 18102. I geni comuni ai due stadi sono stati 10172, mentre 12866 erano solo espressi nelle gemme e 7930 solo nei fiori aperti senescenti.
La lunghezza media delle sequenze ottenute è stata di 319, 2 bp, con una media di 339,11 bp nelle gemme e 296,4 bp nei fiori aperti/senescenti.
L’analisi del profilo di espressione ha individuato una totale di 4.188 geni differenzialmente espressi tra la gemma e il fiore parzialmente senescente, tra i quali 2.053 sono risultati essere sovra-regolati mentre 2.135 sotto-regolati. Inoltre i geni sono stati classificati in differenti categorie funzionali mediante Gene Ontology (GO) e sulla base della loro similarità di sequenza a proteine note nel database UniProt annotate con domini InterPro e COG. I risultati ottenuti consentiranno di delucidare i meccanismi molecolari coinvolti nel processo di senescenza fiorale e forniranno una vasta risorsa genomica che faciliterà il miglioramento genetico e sarà indispensabile per ricerche future su questa specie
Effects of abscisic acid on ethylene biosynthesis and perception in Hibiscus rosa-sinensis L. flower development
No full textThe effect of the complex relationship between ethylene and abscisic acid (ABA) on flower development and
senescence in Hibiscus rosa-sinensis L. was investigated. Ethylene biosynthetic (HrsACS and HrsACO) and receptor
(HrsETR and HrsERS) genes were isolated and their expression evaluated in three different floral tissues (petals,
style–stigma plus stamens, and ovaries) of detached buds and open flowers. This was achieved through treatment
with 0.1 mM 1-aminocyclopropane-1-carboxylic acid (ACC) solution, 500 nl l21 methylcyclopropene (1-MCP), and
0.1 mM ABA solution. Treatment with ACC and 1-MCP confirmed that flower senescence in hibiscus is ethylene
dependent, and treatment with exogenous ABA suggested that ABA may play a role in this process. The 1-MCP
impeded petal in-rolling and decreased ABA content in detached open flowers after 9 h. This was preceded by an
earlier and sequential increase in ABA content in 1-MCP-treated petals and style–stigma plus stamens between 1 h
and 6 h. ACC treatment markedly accelerated flower senescence and increased ethylene production after 6 h and
9 h, particularly in style–stigma plus stamens. Ethylene evolution was positively correlated in these floral tissues
with the induction of the gene expression of ethylene biosynthetic and receptor genes. Finally, ABA negatively
affected the ethylene biosynthetic pathway and tissue sensitivity in all flower tissues. Transcript abundance of
HrsACS, HrsACO, HrsETR, and HrsERS was reduced by exogenous ABA treatment. This research underlines the
regulatory effect of ABA on the ethylene biosynthetic and perception machinery at a physiological and molecular
level when inhibitors or promoters of senescence are exogenously applied
Interaction of 1-Methylcyclopropene and Thidiazuron on Cut Stock Flowers Vase Life
Full text linkLeaf yellowing or petal senescence is the main postharvest disorder for many cut flowers. Plant hormones such as cytokinins are able to inhibit leaf yellowing in some cut flowers and potted plants. In our experiments, we applied thidiazuron aiming to delay leaf yellowing and 1-methylciclopropene (1-MCP) for inhibiting flower senescence of cut stock flowers during vase life. Cut flowers were pulse treated with water (control), 5 μM TDZ, 500 nL L-1 1-MCP or combinations 5 μM TDZ+500 nL L-1 1-MCP, 5 μM TDZ+500 nL L-1 1-MCP+10 μmL L-1 ethylene or 10 μL L-1 ethylene. All treatments were applied for 24 h (pulse), except for the 1-MCP that was applied for 6 h. The effect of treatments was evaluated by chlorophyll determination, petal fall, leaf yellowing appearance, vase life and ethylene production.
Pulse treatment with TDZ was able to delay leaf yellowing in light during whole experimental period (30 days). During the first days after TDZ treatment, the chlorophyll b biosynthesis was strongly induced, after 5 days were the initial val-ues, 3-fold higher while the total chlorophyll did not change. The TDZ stimulated ethylene production such as 1-MCP as soon as after 24 h. The ethylene production was found in cut flowers treated with ethylene, reaching 9 nl g-1 h-1 in leaves and 6.5 nl g-1 h-1 in detached flowers. The 1-MCP dramatically reduced the efficiency of TDZ even if the vase life of cut flowers was extended compared with controls
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