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Start Over Creator Procházková, D.

2. Content of carotenoids during ageing and senescence of tobacco leaves with genetically modulated life-span

Creator:
Procházková, D., Haisel, D., and Wilhelmová, N.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
cytokinin, reactive oxygen species, and xanthophylls
Language:
Multiple languages
Description:
We exploited leaves of tobacco (Nicotiana tabacum L., cv. Wisconsin 38) with introduced chimeric construct consisting of SAG12 promoter fused with ipt gene for cytokinin synthesis and therefore prolonged life-span. As a control we used its wild type. In 12-week-old plants, the first leaves of control plants showed senescence symptoms at the time of sampling. Carotenoid content decreased with increasing leaf age both in control and in transgenic plants. On the other hand, the first leaves of transgenic plants demonstrated better antioxidant capacity represented by carotenoids compared to the leaves of control plants of the same age. They stayed still green at this age. and D. Procházková, D. Haisel, N. Wilhelmová.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Effects of exogenous nitric oxide on photosynthesis

Creator:
Procházková, D., Haisel, D., Wilhelmová, Naďa, Pavlíková, Daniela, and Száková, Jiřina
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, chlorophyll fluorescence, chloroplast, nitration, nitrotyrosine, 2, and 581
Language:
Multiple languages
Description:
Nitric oxide (NO) is an important signalling molecule with diverse physiological functions in plants. In plant cell, it is synthesised in several metabolic ways either enzymatically or nonenzymatically. Due to its high reactivity, it could be also cytotoxic in dependence on concentration. Such effects could be also mediated by NO-derived compounds. However, the role of NO in photosynthetic apparatus arrangement and in photosynthetic performance is poorly understood as indicated by a number of studies in this field with often conflicting results. This review brings a short survey of the role of exogenous NO in photosynthesis under physiological and stressful conditions, particularly of its effect on parameters of chlorophyll fluorescence. and D. Procházková ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Photosynthesis in leaves of Nicotiana tabacum L. infected with tobacco mosaic virus

Creator:
Wilhelmová, N., Procházková, D., Šindelářová, M., and Šindelář, L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
carotenoids, chlorophyll, chlorophyll fluorescence, electron transport, photosynthetic efficiency, photosystem 2, and tobacco
Language:
Multiple languages
Description:
In tobacco leaves inoculated with tobacco mosaic virus (TMV), changes in chlorophyll (Chl) and carotenoid contents, parameters of slow Chl fluorescence kinetics, i.e. the maximum quantum yield of photosystem (PS2) photochemistry Fv/Fm, the effective quantum yield of photochemical energy conversion in PS2 Φ2, ratio of quantum yields of photochemical and concurrent non-photochemical processes in PS2 Fv/F0, non-photochemical quenching (NPQ), and photochemical activities of isolated chloroplasts from systemically infected tobacco leaves were investigated. We compared two successive stages of infection, the first in the stage of vein clearing at 9th day post inoculation (dpi) and the second at 22nd dpi when two different regions, i.e. light- (LGI) or dark-green (DGI) islands in the infected leaf were apparent and symptoms were fully developed. These two different regions were measured separately. The Chl and carotenoid contents in infected leaves decreased with a progression of infection and were lowest in LGI in the second stage. Also the ratio of Chl a/b declined in similar manner. The maximum quantum yield of PS2 photochemistry Fv/Fm, was decreased in the following order: first stage, DGI, and LGI. The same is true for the ratio Fv/F0. The decrease of Φ2 in infected leaves declined as compared to their controls. On the contrary, NPQ increased in infected leaves, the highest value was found in the first infection stage. Photochemical activities of the whole electron transport chain in isolated chloroplasts dramatically declined with the progression of symptoms, the lowest value was in LGI. Similarly, but to a lesser extent, the activity of PS2 in isolated chloroplasts decreased in infected leaves. Generally, the most marked impairment of the photosynthetic apparatus was manifested in the LGI of infected leaves. and N. Wilhelmová ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public