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2. Effect of iron, zinc and manganese shortage-induced change on photosynthetic pigments, some osmoregulators and chlorophyll fluorescence parameters in lettuce

Creator:
Roosta, H. R., Estaji, A., and Niknam, F.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
železo, zinek, mangan, iron, zinc, manganese, mikronutrienty, locika setá, kvantový výtěžek, fotosyntetické pigmenty, chlorophyll fluorescence transients, mikronutrients, Lactuca sativa, quantum yield, photosynthetic pigments, 2, and 581
Language:
Multiple languages
Description:
Although the beneficial role of Fe, Zn, and Mn on many physiological and biochemical processes is well established, effects of each of these elements on chlorophyll (Chl) a fluorescence and photosynthetic pigment contents is not well studied. The objective of this study was to evaluate effects of Fe, Zn, and Mn deficiency in two lettuce cultivars. The parameters investigated could serve also as physiological and biochemical markers in order to identify stress-tolerant cultivars. Our results indicated that microelement shortage significantly decreased contents of photosynthetic pigments in both lettuce cultivars. Chl a fluorescence parameters including maximal quantum yield of PSII photochemistry and performance index decreased under micronutrient deficiency, while relative variable fluorescence at J-step and minimal fluorescence yield of the dark-adapted state increased under such conditions in both cultivars. Micronutrient deficiency also reduced all parameters of quantum yield and specific energy fluxes excluding quantum yield of energy dissipation, quantum yield of reduction of end electron acceptors at the PSI, and total performance index for the photochemical activity. Osmoregulators, such as proline, soluble sugar, and total phenols were enhanced in plants grown under micronutrient deficiency. Fe, Zn, and Mn deficiency led to a lesser production of dry mass. The Fe deficiency was more destructive than that of Zn and Mn on the efficiency of PSII in both lettuce cultivars. Our results suggest that the leaf lettuce, which showed a higher efficiency of PSII, electron transport, quantum yield, specific energy fluxes, and osmoregulators under micronutrient deficiency, was more tolerant to stress conditions than crisphead lettuce., H. R. Roosta, A. Estaji, F. Niknam., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Trace elements have beneficial, as well as detrimental effects on bone homeostasis

Creator:
Ivana Žofková, Davis, M., and Jaroslav Blahoš
Format:
print, bez média, and svazek
Type:
article, články, journal articles, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, bor, kadmium, měď, železo, olovo, hořčík, mangan, selen, zinek, boron, cadmium, copper, iron, lead, magnesium, manganese, selenium, zinc, bone mineral density, bone quality, fluoride, 14, and 612
Language:
English
Description:
The protective role of nutrition factors such as calcium, vitamin D and vitamin K for the integrity of the skeleton is well understood. In addition, integrity of the skeleton is positively influenced by certain trace elements (e.g. zinc, copper, manganese, magnesium, iron, selenium, boron and fluoride) and negatively by others (lead, cadmium, cobalt). Deficiency or excess of these elements influence bone mass and bone quality in adulthood as well as in childhood and adolescence. However, some protective elements may become toxic under certain condition s, depending on dosage (serum concentration), duration of treatment and interactions among individual elements. We review the beneficial and toxic effects of key elements on bone homeostasis., I. Zofkova, M. Davis, J. Blahos., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public