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Start Over Creator Vičánková, A.

1. Maize F1 hybrid differs from its maternal parent in the development of chloroplasts in bundle sheath, but not in mesophyll cells: Quantitative analysis of chloroplast ultrastructure and dimensions in different parts of leaf blade at the beginning of its senescence

Creator:
Vičánková, A., Holá, D., and Kutík, J.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chloroplast development, electron microscopy, genetic variability, granal thylakoids, leaf blade heterogeneity, peripheral reticulum, plastoglobuli, starch inclusions, and Zea mays
Language:
Multiple languages
Description:
The quantitative changes of chloroplast ultrastructure and dimensions in mesophyll (MC) and bundle sheath (BSC) cells, associated with the onset of leaf senescence, were followed along the developmental leaf blade gradient of the third leaf of maize (Zea mays L.). To ascertain whether the rapidity of structural changes associated with the transition of chloroplasts from mature to senescent state is a heritable trait, the parental and the first filial generations of plants were used. The heterogeneity of leaf blade, associated with the development of maize leaf (with the oldest regions at the apex and the youngest ones at the base) was clearly discernible in the ultrastructure and dimensions of chloroplasts; however, there were differences in the actual pattern of chloroplast development between both genotypes as well as between both cell types examined. While the course of MC chloroplasts' development at the onset of leaf senescence in maize hybrid followed that of its parent rather well, this did not apply for the BSC chloroplasts. In this case, each genotype was characterized by its own distinguishable developmental pattern, particularly as regards the accumulation of starch inclusions and the associated changes of the size and shape of BSC chloroplasts. and A. Vičánková, D. Holá, J. Kutík.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. The heterogeneity of structural and functional photosynthetic characteristics of mesophyll chloroplasts in various parts of mature or senescing leaf blade of two maize (Zea mays L.) genotypes

Creator:
Kutík, J., Holá, D., Vičánková, A., Šmídová, M., Kočová, M., Körnerová, M., and Kubínová, L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chloroplast development, chloroplast dimensions, electron microscopy, Hill reaction activity, peripheral reticulum, photosynthesis, photosystem 1 activity, plastoglobuli, and thylakoids
Language:
Multiple languages
Description:
Differences in ultrastructural parameters of mesophyll cell (MC) chloroplasts, contents of photosynthetic pigments, and photochemical activities of isolated MC chloroplasts were studied in the basal, middle, and apical part of mature or senescing leaf blade of two maize genotypes. A distinct heterogeneity of leaf blade was observed both for structural and functional characteristics of chloroplasts. In both mature and senescing leaves the shape of MC chloroplasts changed from flat one in basal part of leaf to nearly spherical one in leaf apex. The volume density of granal thylakoids decreased from leaf base to apex in both types of leaves examined, while the amount of intergranal thylakoids increased in mature leaves but decreased in senescing leaves. The most striking heterogeneity was found for the quantity of plastoglobuli, which strongly increased with the increasing distance from leaf base. The differences in chloroplast ultrastructure were accompanied by differences in other photosynthetic characteristics. The Hill reaction activity and activity of photosystem 1 of isolated MC chloroplasts decreased from leaf base to apex in mature leaves. Apical part of senescing leaf blade was characterised by low contents of chlorophyll (Chl) a and Chl b, whereas in mature leaves, the content of Chls as well as the content of total carotenoids (Car) slightly increased from basal to apical leaf part. This was reflected also in the ratio Chl (a+b)/total Car; the ratio of Chl a/b did not significantly differ between individual parts of leaf blade. Both genotypes examined differed in the character of developmental gradient observed along whole length of leaf blade. and J. Kutík ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. The ultrastructure of chloroplasts, content of photosynthetic pigments, and photochemical activity of maize (Zea mays L.) as influenced by different concentrations of the herbicide amitrole

Creator:
Pechová, R., Kutík, J., Holá, D., Kočová, M., Haisel, D., and Vičánková, A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
3-amino-1,2,4-triazole, carotenoids, chlorophylls, Hill reaction, and photosystems 1 and 2
Language:
Multiple languages
Description:
The effect of three different concentrations of amitrole (AM), a bleaching herbicide affecting carotenogenesis, on chloroplast ultrastructure, photosynthetic pigment contents, and photochemical activity was studied in two maize genotypes differing in photosynthetic characteristics. The content of photosynthetic pigments in leaves of plants treated with low (20 μM) AM concentration was similar to control plants and no damaging effect of the herbicide on the ultrastructure of either mesophyll (MC) or bundle-sheath (BSC) cell chloroplasts was observed. Higher (60 and 120 μM) concentrations of AM caused a significant decrease in the content of carotenoids (especially xanthophylls), which was followed by photooxidative destruction of chlorophylls and some alterations of chloroplast ultrastructure. MC chloroplasts appeared more sensitive to the damaging effect of AM compared to BSC chloroplasts. A significant decrease in the amount of both granal and intergranal thylakoids in MC chloroplasts was observed with the increasing concentration of AM. As regards BSC chloroplasts, rapid decrease in the volume density of starch inclusions was found in plants treated with higher concentrations of AM. When 120 μM AM was used, both MC and BSC chloroplasts contained just a few thylakoid membranes that were strongly altered. The changes in the ultrastructure of MC chloroplasts were accompanied by the changes in their photochemical activity. The formation of chloroplast protrusions after treatment of plants with AM as well as in control plants was also observed. and R. Pechová ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public