Η επίδραση του H2O2 και του NO στους αντιοξειδωτικούς μηχανισμούς σπορόφυτων νεραντζιάς (Citrus aurantium L.) σε συνθήκες αλατότητας

Περίληψη

Η αλατότητα αποτελεί σημαντικό πρόβλημα για τα καλλιεργουμενα φυτά. Τα τελευταία έτη πραγματοποιήθηκαν ερευνητικές προσπάθειες προκειμένου να ενεργοποιηθούν οι μεταβολικές οδοί άμυνας και προσαρμογής των φυτών στην αλατότητα. Το Η2Ο2 και το NO• θεωρούνται μόρια επαγωγής μοριακών ερεθισμάτων για την ενεργοποίηση των μεταβολικών οδών που συνδέονται με τους αμυντικούς μηχανισμούς των φυτών. Έτσι, στην παρούσα διδακτορική διατριβή διερευνήθηκε εάν η εξωγενής προμεταχείριση σποροφύτων νεραντζιάς (Citrus aurantium) με Η2Ο2 ή με νιτροπρωσσικό νάτριο (SNP- δότης NO•) μπορεί μετέπειτα να προκαλέσει αντοχή στην αλατότητα. Για το σκοπό αυτό, σπορόφυτα νεραντζιάς ηλικίας 5 μηνών προμεταχειρίσθηκαν με Η2Ο2 (10 mΜ, 8 h) ή με SNP (100 μΜ, 48 h) και στη συνέχεια αναπτύχθηκαν υδροπονικά χωρίς ή με 150 mM NaCl για 16 ημέρες. Δείγματα φύλλων και ριζών παραλήφθηκαν αμέσως μετά τις προμεταχειρίσεις (ημέρα 0) καθώς και τη 2, 4, 8 και 16η ημέρα. Έντονα συμπτώματα αλατότητας παρατηρήθηκαν στα φύλλα της μεταχε ...
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Περίληψη σε άλλη γλώσσα

most serious environmental stresses reducing plant production. Many studies have been conducted lately aiming at stimulating the salinity defence and adaptation metabolic pathways. Hydrogen peroxide and NO• are considered among the signaling molecules mediating the plant response metabolic pathways. In the present PhD thesis, the hypothesis of triggering the sour orange (Citrus aurantium) salinity adaptation mechanism via previous exogenous pre-treatment with Η2Ο2 or SNP (NO• donor) was studied. For this purpose 5-month old sour orange seedlings were pre-treated with Η2Ο2 (10 mΜ, 8 h) or SNP (100 μΜ, 48 h) and then hydroponically cultured for 16 days with or without 150 mM NaCl. After the end of the pre-treatment period (day 0), leaf and root samples were collected as well as at the days 2, 4, 8 and 16. In the leaves of NaCl-treated seedlings, more severe salinity symptoms were observed than in the leaves treated with Η2Ο2+NaCl or SNP+NaCl. During the experimenta ...
Salinity is one of the most serious environmental stresses reducing plant production. Many studies have been conducted lately aiming at stimulating the salinity defence and adaptation metabolic pathways. Hydrogen peroxide and NO• are considered among the signaling molecules mediating the plant response metabolic pathways. In the present PhD thesis, the hypothesis of triggering the sour orange (Citrus aurantium) salinity adaptation mechanism via previous exogenous pre-treatment with Η2Ο2 or SNP (NO• donor) was studied. For this purpose 5-month old sour orange seedlings were pre-treated with Η2Ο2 (10 mΜ, 8 h) or SNP (100 μΜ, 48 h) and then hydroponically cultured for 16 days with or without 150 mM NaCl. After the end of the pre-treatment period (day 0), leaf and root samples were collected as well as at the days 2, 4, 8 and 16. In the leaves of NaCl-treated seedlings, more severe salinity symptoms were observed than in the leaves treated with Η2Ο2+NaCl or SNP+NaCl. During the experimental period, the roots in salinity treatments (NaCl, Η2Ο2+NaCl, SNP+NaCl) had high Na+ and Cl- concentrations. Comparing to the ionic concentration in the leaves of the NaCl treatment, the Na+ and Cl- were lower until the 16th day in the leaves of Η2Ο2+NaCl treated seedlings and until the 4th (Na+) and 8th (Cl-) day, in the leaves of the SNP+NaCl treatment. NO• was detected in the leaf vascular bundles and the epidermal cells. Hydrogen peroxide or SNP pretreatment increased leaf and root Η2Ο2 content from day 0 until day 16th. Salinity treatments induced Η2Ο2 and MDA production in the plant tissues. However, in comparison to NaCl treatment, Η2Ο2 concentration was higher in the leaves of Η2Ο2+NaCl treatment and in the SNP+NaCl roots. Moreover MDA concentration was lower in the leaves of Η2Ο2+NaCl and SNP+NaCl treatments compared to NaCl treatment. Root and leaf deoxyribose and plasmid pBR322 DNA, both protecting against HO• were in general decreased due to Η2Ο2, SNP, Η2Ο2+NaCl, SNP+NaCl application and predominantle to NaCl. The latter caused furthermore the detection of prooxidant compounds in the root extracts the 8th and 16th day. Hydrogen peroxide pretreatment increased immediately (day 0) leaf Put content and decreased leaf Spd and root Put. At the same time (day 0), SNP pretreatment increased root Spd and decreased leaf Put and Spd. Salinity treatments caused time and tissue-dependent changes in PAs content. The most notable changes include the leaf Put and Spd decrease due to all salinity treatments, the Put decrease the NaCl and SNP+NaCl roots and the transient increase of Spm in the leaves (the 2nd day in all salinity treatments; the 4th day in Η2Ο2+NaCl treatment) and Spd in the roots (2nd and 4th day in Η2Ο2+NaCl and SNP+NaCl treatments; 8th day in Η2Ο2+NaCl treatment). The NaCl και SNP+NaCl treatments caused a gradient decrease of the root total antioxidant power (FRAP values). FRAP values remained unchanged in the leaves of NaCl treatment but increased in the leaves of Η2Ο2, SNP, Η2Ο2+NaCl, SNP+NaCl treatments. The Η2Ο2 pretreatment decreased the ratio ΑA/(ΑA+DHA) in the roots (during the whole experimental period) and in the leaves (only at day 0) whereas the SNP pretreatment in the roots (until the 4th day). During the course of the experiment, apart from the leaves of Η2Ο2+NaCl treated plants, the ratio ΑA/(ΑA+DHA) decreased in all remaining salinity treatments. The glutathione redox state (GSH/GSH+GSSG) was reduced in the roots of the NaCl treated plants, but generally increased in the leaves and the roots of the seedlings treated with SNP or SNP+NaCl and remained unchanged in those treated with Η2Ο2 or Η2Ο2+NaCl.περισσότερα
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DOI
10.12681/eadd/15184
Διεύθυνση Handle
http://hdl.handle.net/10442/hedi/15184
ND
15184
Εναλλακτικός τίτλος
The effect of H2O2 and NO on the antioxidant mechanism of sour orange seedlings (Citrus aurantium L.) grown under salinity conditions
Συγγραφέας
Τάνου, Γεωργία (Πατρώνυμο: Θωμάς)
Ημερομηνία
2007
Ίδρυμα
Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ). Σχολή Γεωπονική
Εξεταστική επιτροπή
Διαμαντίδης Γρηγόριος
Βασιλακάκης Μιλτιάδης
Σιώμος Αναστάσιος
Κωνσταντινίδου Ελένη
Κανέλλης Άγγελος
Γιουψάνης Τραϊανός
Μολασιώτης Αθανάσιος
Επιστημονικό πεδίο
Γεωπονικές Επιστήμες και Κτηνιατρική
Γεωπονική Βιοτεχνολογία
Λέξεις-κλειδιά
Αλατότητα; Οξειδωτική καταπόνηση; Υπεροξείδιο υδρογόνου; Οξείδιο αζώτου; Εσπεριδοειδή; Πρωτεομική ανάλυση
Χώρα
Ελλάδα
Γλώσσα
Ελληνικά
Άλλα στοιχεία
202 σ., εικ.