Leaf Hairs of Olive (Olea-Europaea) Prevent Stomatal Closure by Ultraviolet-B Radiation
Φόρτωση...
Ημερομηνία
Συγγραφείς
Grammatikopoulos, G.
Karabourniotis, G.
Kyparissis, A.
Petropoulou, Y.
Manetas, Y.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Australian Journal of Plant Physiology
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
In olive (Olea europaea L.), hair removal had no effect on the photosynthetic rate and the apparent leaf resistance to water vapour diffusion in leaves illuminated with white light (900 mu mol m(-2) s(-1) photosynthetically active radiation) devoid of ultraviolet-B radiation. In addition, intact and dehaired leaves showed no significant differences in absorptance in the visible spectral region, while leaf temperature was independent of hair removal. These results indicate that leaf hairs of O. europaea may play only a marginal role in leaf energy balance and transpiration. When the white light was supplemented with ultraviolet-B radiation (5.89 W m(-2)), however, there was a considerable decrease in the photosynthetic rate, and a simultaneous increase in leaf resistance to water vapour in dehaired leaves. Photochemical efficiency of photosystem II, evaluated from chlorophyll fluorescence emitted from the illuminated side, was reduced in all cases, but the reduction in dehaired, ultraviolet-B treated leaves was more pronounced and irreversible, indicating that the reduction of the photosynthetic rate may result from both stomatal limitation and electron flow inhibition. Photosynthetic capacity of dehaired leaves, measured at 5% CO2, however, was not influenced by ultraviolet-B radiation. We suggest, therefore, that ultraviolet-B radiation reduces photosynthetic rates by closing the stomata, while the observed reduction in photosystem II photochemical efficiency may concern only a superficial chloroplast population, contributing negligibly to whole leaf photosynthesis. Under the conditions of our experiments, the protective function of the indumentum against ultraviolet-B radiation predominates over the water conservation function.
Περιγραφή
Λέξεις-κλειδιά
uv-b, chlorophyll fluorescence, photosystem-ii, higher-plants, flux-density, gas-exchange, photosynthesis, leaves, rice, temperature
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://A1994NN43700004
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών