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2. Decline in photosynthesis as related to alterations in chloroplast ultrastructure of a cotton leaf during ontogeny
- Creator:
- Bondada, Bhaskar Rao and Oosterhuis, D. M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Gossypium hirsutum, grana, plastoglobuli, and stroma lamellae
- Language:
- Multiple languages
- Description:
- Field studies were conducted to investigate ontogenic changes in leaf photosynthesis and chloroplast ultrastructure of a single cotton (Gossypium hirsutum L.) leaf subtending the fruit. A 20-d old leaf was the most physiologically active with net photosynthetic rate (PN) of 16.5 μmol m-2 s-1 and nitrogen (N) concentration of 168 mmol m-2. These values declined with leaf age and a close relationship existed between them. Concurrent with declines in PN, ultrastructural alterations occurred in the chloroplast: the 20-d old leaf had increased grana number and thylakoids per granum and a few plastoglobuli. Afterwards, the grana number and thylakoids per granum declined with leaf age indicating disintegrated grana and stroma lamellae. Concomitant with disintegrated membrane system was the presence of numerous large plastoglobuli. The PN was closely related to grana number and thylakoids per granum suggesting that the decline in PN with leaf age was associated with ultrastructural changes in the chloroplast. and Bhaskar Rao Bondada, D. M. Oosterhuis.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Low-temperature induced changes in the ultrastructure of maize mesophyll chloroplasts strongly depend on the chilling pattern/intensity and considerably differ among inbred and hybrid genotypes
- Creator:
- Holá, D., Kutík, J., Kočová, M., and Rothová, O.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- inheritance, peripheral reticulum, photosynthesis, plastoglobuli, stress, thylakoid, and volume density
- Language:
- Multiple languages
- Description:
- The ultrastructure and dimensions of chloroplasts in leaf mesophyll cells were quantitatively examined in three parental inbred lines of maize (Zea mays L.) and their four hybrids subjected to two types of four-week low-temperature (LT) treatment: the abrupt onset of chilling temperatures ("severe chilling", SC) and the gradual, more moderate one ("moderate chilling", MC). The relationship between the response of individual genotypes to one or the other type of chilling was analyzed as well as the possibility to predict the behaviour of chloroplasts in hybrids from that of their parents. Although selected parameters of chloroplast ultrastructure (e.g. volume densities of granal and intergranal thylakoids, plastoglobuli, and peripheral reticulum) and dimensions changed due to the exposure of maize plants to LT, no general pattern of such changes was found for this species due to the observed intraspecific variability. The response of some genotype to SC could not be predicted from its behaviour under MC (and vice versa) and no clear rules could be applied for the inheritance of chloroplast response to chilling in the general sense. Thus, great caution should be always taken when interpreting the results of studies aimed at the dissection of chloroplast ultrastructure as affected by LT, particularly in case such studies are made with one genotype or under one type of chilling only. and D. Holá ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. 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
5. Ontogenic changes in epicuticular wax and chloroplast integrity of a cotton (Gossypium hirsutum L.) leaf
- Creator:
- Bondada, B. R. and Oosterhuis, D. M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- grana, microscopy, plastoglobuli, and stroma lamellae
- Language:
- Multiple languages
- Description:
- The progressive decline in cotton leaf photosynthesis with season could be accounted for by gaining an insight into ontogenic changes in chloroplast integrity and epicuticular wax ultrastructure. Therefore, the sequence of ultrastructural changes in chloroplast and epicuticular wax morphology were probed in 10-, 20-, 40-, and 60-d-old cotton (Gossypium hirsutum L.) leaves using electron microscopy. Scanning electron microscopy illustrated that the epicuticular wax on the periclinal walls of the convex epidermal cells occurred as striations and persisted as such during the course of leaf aging. The degree of wax spread, however, increased as the leaf progressed towards senescence. Transmission electron microscopy revealed that a 20-d-old photosynthetically active leaf possessed healthy chloroplasts (6.8 μm long and an area of 9.7 μm2) with absolute membrane integrity depicted by large appressed grana stacks of thylakoids interconnected by non-appressed stroma lamellae. The thylakoid membrane network was oriented parallel to the long axis of the chloroplast and a few small plastoglobuli (1.85 μm2) scattered in the stroma. Conversely, membrane integrity was lost with leaf age after 20 d as evidenced by disruption of the grana and stroma lamellae. Concurrent with the membrane damage, extensive occlusion of chloroplast by several large spherical plastoglobuli (5.68 μm2) occurred, the rate of occlusion increased with leafage distending the chloroplast as evidenced by proliferation of its cross-sectional area (12.8 μm2). Of particular interest was the finding that the plastoglobuli ensued through the chloroplast envelope into the cytoplasm. The progressive loss of chloroplast membrane integrity coupled with increased leaf waxiness may have limited photosynthetic activities of cotton leaves during senescence. and B. R. Bondada, D. M. Oosterhuis.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6. Physiological and biochemical responses of two tree species in urban areas to different air pollution levels
- Creator:
- Baek, S. G. and Woo, S. Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, antioxidant enzyme, chlorophyll content, chloroplasts, photosynthetic rate, and plastoglobuli
- Language:
- Multiple languages
- Description:
- We investigated the physiological and biochemical differences in Pterocarpus indicus and Erythrina orientalis grown in four sites at different pollution levels in the Philippines: Makati, Pasig and Quezon (high pollution levels; HP) located in Metro Manila, and La Mesa Watershed (a non-polluted area; NP). Among these four areas, HP sites had higher net photosynthetic rates (PN) than NP sites, except for Makati. Among HP sites, Makati and Quezon had the lowest PN for P. indicus and E. orientalis, respectively. Chlorophyll (Chl) contents were significantly lower in HP than in NP sites. Trees in Makati had the lowest Chl contents among HP sites, and P. indicus had higher Chl contents than did E. orientalis. In addition, the chloroplasts in HP trees had small starch grains with numerous dark, large plastoglobuli. Furthermore, antioxidant enzymes, indicative of the defense mechanism, showed a significantly higher activity in HP than in NP trees. and S. G. Baek, S. Y. Woo.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7. The development of chloroplast ultrastructure and Hill reaction activity during leaf ontogeny in different maize (Zea mays L.) genotypes
- Creator:
- Kutík, J., Kočová, M., Holá, D., and Körnerová, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chloroplast dimensions, electron microscopy, peripheral reticulum, photosynthesis, plastoglobuli, starch, stereology, stroma, and thylakoids
- Language:
- Multiple languages
- Description:
- Changes in Hill reaction activity (HRA) and ultrastructure of mesophyll cell (MC) chloroplasts were studied during the ontogeny of third leaf of maize plants using polarographic oxygen evolution measurement, transmission electron microscopy, and stereology. The chloroplast ultrastructure was compared in young (actively growing), mature, and senescing leaves of two different inbreds and their reciprocal F1 hybrids. Statistically significant differences in both HRA and MC chloroplast ultrastructure were observed between different stages of leaf ontogeny. Growth of plastoglobuli was the most striking characteristic of chloroplast maturation and senescence. The chloroplasts in mature and senescing leaves had a more developed system of thylakoids compared to the young leaves. Higher HRA was usually connected with higher thylakoid volume density of MC chloroplasts. and J. Kutík ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8. 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
9. Ultrastructure and dimensions of chloroplasts in leaves of three maize (Zea mays L.) inbred lines and their F1 hybrids grown under moderate chilling stress
- Creator:
- Kutík, J., Holá, D., Kočová, M., Rothová, O., Haisel, D., Wilhelmová, N., and Tichá, I.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- bundle sheath cells, electron microscopy, genotypes, heterosis, intra-specific variability, mesophyll cells, peripheral reticulum, plastoglobuli, stereology, and thylakoids
- Language:
- Multiple languages
- Description:
- Influence of moderate chilling stress on vascular bundle sheath cell (BSC) and especially mesophyll cell (MC) chloroplasts of mature maize leaves was studied by electron microscopy and stereology. Plants of two inbred lines of maize, differing in their photosynthetic activity, and their F1 hybrids were cultivated during autumn in heated or unheated glasshouse. Generally, chilling temperatures resulted mainly in the decrease in stereological volume density (VD) of both granal and intergranal thylakoids of MC chloroplasts, while the ratio of granal to all thylakoids (granality) was less affected. The VD of peripheral reticulum and plastoglobuli usually increased after cold treatment of plants. The volume of MC chloroplasts usually increased under chilling stress, the shape of the chloroplasts changed only slightly. The ultra-structure of chloroplasts differed between individual genotypes; chilling-stressed hybrid plants showed positive heterosis particularly in the granal thylakoids' VD of MC chloroplasts. and J. Kutík ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public