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2. Changes in the near-UV fluorescence excitation spectrum during protochlorophyllide photoreduction in etiolated cucumber cotyledons

Creator:
Durchan, M. and Lebedev, N.
Format:
print
Type:
model:internalpart and TEXT
Subject:
Cucumis sativus L., energy transfer, protochlorophyllide reductase, and Shibata shift
Language:
Multiple languages
Description:
Fluorescence excitation spectra of different protochlorophyll(ide) (PChlide) a forms in intact etiolated cucumber cotyledons showed a pronounced increase in intensity of the 390 nm band in comparison with spectra of the pigment in Solutions. The native PChlide F657 also had an additional band at 360 nm in its excitation spectra, which disappeared after leaf homogenization and was restored by addition of dithionite. The restoration correlated with changes around 340 nm in the excitation spectrum of blue-green fluorescence. In consideration of this fact, the 360 nm band seems to correspond to energy transfer from NADPH to PChlide a. After the onset of irradiation a new band appeared at 380 nm in the excitation spectrum of the main pigment fluorescence, which was very similar to that found in the absorption spectinm of isolated Chl a. Moreover, in the Soret region the excitation spectrum had a double band splitting which disappeared only after the Shibata shift, simultaneously with the disappearance of the 360 nm band. Besides the well-known PChl(ide) F633, F642, and F657 forms, etiolated cucumber cotyledons háve emission at 673 nm. Its excitation spectrum was hardly distinguishable from the PChlide F657 fluorescence excitation spectrum in etiolated samples. In the irradiated plants this band had excitation spectrum of monomeric Chl a. The intensity of band at 673 run decreased and transiently increased after PChlide photoconversion. The dynamics of these fluorescence intensity changes under inadiation showed positive correlation both with PChlide F657 and with PChl(ide) F642, indicating the short wavelength Chl a preexistence in etiolated plants and its additional formation after the onset of irradiation.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Variations of leaf morphology, photosynthetic traits and water-use efficiency in Western-Mediterranean tomato landraces

Creator:
Fullana-Pericàs, M., Conesa, M. À., Soler, S., Ribas-Carbó, M., Granell, A., and Galmés, J.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
asimilace uhlíku, izotopové složení uhlíku, difúzní omezen, morfologie listu, efektivita využívání vody, rajče, carbon assimilation, carbon isotope composition, diffusive limitations, mesophyll conductance, leaf morphology, water-use efficiency, tomato, 2, and 581
Language:
Multiple languages
Description:
Modern tomato (Solanum lycopersicum L.) breeding has mainly focused on increasing productivity under unlimited watering. In contrast, some Mediterranean accessions have been traditionally cultivated under water shortage and selected on the basis of their water-use efficiency (WUE). Ramellet and Penjar landraces were planted with other traditional, old and modern inbreeds, under full irrigation. In order to found differences between the tomato accessions, gas-exchange and leaf morphology measurements were performed. Despite high variability, Ramellet and Penjar presented clear differences compared to modern cultivars, mostly related to leaf morphology and photosynthetic traits, while no differences were found in WUE. Results highlighted that better leaf CO2 conductance might be a main factor determining the improvement of net CO2 assimilation and WUE., M. Fullana-Pericàs, M. À. Conesa, S. Soler, M. Ribas-Carbó, A. Granell, J. Galmés., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public