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Start Over Subject chlorophyll fluorescence induction

21. The antenna size of QB-reducing photosystem 2 complexes in different fractions of subchloroplast particles

Creator:
Kornyeyev, D. Y.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
appressed and non-appressed thylakoids, chlorophyll fluorescence induction, and Pisum sativum
Language:
Multiple languages
Description:
The antenna sizes of QB-reducing photosystem 2 (PS2) complexes in two different fractions of the subchloroplast particles were compared by measuring time corresponding to the second maximum of the first derivative from induction curve of chlorophyll fluorescence as a function of actinic irradiance. The QB-reducing PS2 complexes in the fraction of particles that originated from inner parts of grana thylakoids had smaller antennae than those in the fraction from non-appressed regions of thylakoid membranes.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

22. The photosynthetic performance of sterile and fertile sporophytes in a natural population of the fern Dryopteris affinis

Creator:
Paoli, L. and Landi, M.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, chlorophyll fluorescence induction, JIP-test, Mediterranean area, performance index, photosynthesis, pteridophytes, 2, and 58
Language:
Multiple languages
Description:
We studied the photosynthetic performance of sterile and fertile sporophytes in a natural population of the fern Dryopteris affinis growing within a riparian forest (Central Italy) using chlorophyll (Chl) a fluorescence transients, the OJIP phase, where O is for the minimum fluorescence, P is for the peak (the maximum), and J and I are inflections. The “vitality” of the samples was assessed by the maximum quantum yield of primary photochemistry obtained indirectly from the fluorescence data (Fv/Fm); in the same way, the so-called performance index (PIABS) was obtained from fluorescence data. The photosynthetic performance (inferred from PIABS) of D. affinis changed significantly with the seasonal development of the fronds. The highest photosynthetic performance was recorded in the summer, corresponding to the period of spore release. The photosynthetic performance decreased in the winter, down to the minimal values of senescent fronds reached at the end of the seasonal cycle (May-June). On the whole, during the seasonal development, sterile and fertile fronds had a similar photosynthetic behaviour, as inferred from fluorescence data. At the end of spore maturation and dispersal (September-October), the fertile fronds showed somewhat lower photosynthetic performance than the sterile fronds, as revealed by PIABS. Being a long-lived fern, confined to humid and undisturbed sites in the Mediterranean, D. affinis deserves to be further investigated as a potential indicator of ecological continuity in Mediterranean riparian forests., L. Paoli, M. Landi., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

23. Xanthophyll cycle activity in detached barley leaves senescing under dark and light

Creator:
Špundová, M., Strzałka, K., and Nauš, J.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
ageing, carotenoids, chlorophyll fluorescence induction, de-epoxidation state, Hordeum vulgare, and photosystem 2
Language:
Multiple languages
Description:
Senescence-induced changes in the xanthophyll cycle activity and chlorophyll (Chl) fluorescence parameters were compared in detached barley (Hordeum vulgare L.) leaf segments kept for 6 d in darkness or under continuous " white light" (90 μmol m-2 s-1). Before detachment of the leaf segments, the plants were grown at periodic regime [12 h light (90 μmol m-2 s-1)/12 h dark]. The de-epoxidation state of the xanthophyll cycle pigments (DEPS) in the leaf samples was determined immediately (the actual DEPS), after 1 h of dark-adaptation (the residual DEPS), and during 14 min of a high-irradiance (HI) exposure (500 μmol m-2 s-1) (HI-induced DEPS). In the light-senescing segments, senescence was delayed pronouncedly compared to dark-senescing ones as the Chl content, the photosystem 2 photochemistry, and electron transport processes were highly maintained. Further, the actual DEPS increased, probably due to the increased mean photon dose. The HI-induced increase in the DEPS was stimulated in the light-senescing segments, whereas it was slowed down in the dark-senescing ones. However, after the 14 min HI-exposure of the dark-senescing segments the HI-induced DEPS was not markedly lower than in the mature leaves, which indicated the maintenance of the xanthophyll cycle operation. and M. Špundová, K. Strzałka, J. Nauš.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public