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1762. Long-term effect of elevated CO2 on spatial differentiation of ribulose-1,5-bisphosphate carboxylase/oxygenase activity in Norway spruce canopy
- Creator:
- Hrstka, M., Urban, O., and Marek, M. V.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- down-regulation, nitrogen, photosynthesis, Picea abies, sun and shade needles, and vertical profile
- Language:
- Multiple languages
- Description:
- Total in vitro activity of RuBPCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) enzyme was assayed spectrophotometrically by the continuous measurement of 3-phosphoglycerate-dependent NADH oxidation in a coupled enzyme system. RuBPCO activities were found in the ranges 1.01-2.76 and 1.23-3.10 µmol(CO2) m-2 s- 1 in current Norway spruce needles growing in ambient (AC) and elevated (EC) CO2 concentration, respectively. RuBPCO activity in AC needles from the upper layer (U) was 11-15 % higher compared to those from the middle (M) layer, and even 44-56 % higher compared to the lower (L) layer of spruce crown. Over the vegetation season, we observed a highly significant decrease of RuBPCO activity in the EC-U needles from 3.10 (July) to 1.60 (October) µmol(CO2) m-2 s-1 as a consequence of downward feedback regulation. Moreover, this down-regulation was not caused by a non-specific decrease in total leaf nitrogen content. and M. Hrstka, O. Urban, M. V. Marek.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1763. Long-time variations in leaf mass and area of Mediterranean evergreen broad-leaf and narrow-leaf maquis species
- Creator:
- Gratani, L. and Varone, L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- dry mass, Erica, leaf life span, leaf mass per area, Phillyrea, Pistacia, Quercus, rainfall, and Rosmarinus
- Language:
- Multiple languages
- Description:
- Morphological (dry mass, DM; surface area, LA; leaf mass per area, LMA), anatomical (leaf thickness, L), phenological (leaf life span, LL), and physiological (net photosynthetic rate, PN) leaf traits of the evergreen species co-occurring in the Mediterranean maquis developing at Castelporziano (Rome) were tested. The correlation analysis indicated that LMA variation was tightly associated with LL variations: Cistus incanus and Arbutus unedo had a short LL (4±1, summer leaves, and 11±1 months, respectively) and low LMA (153±19 g m-2) values, Quercus ilex, Phillyrea latifolia, and Pistacia lentiscus high LMA (204±7 g m-2) and long LL (22±3 months), Erica arborea, Erica multiflora, and Rosmarinus officinalis a short LL (9±2 months) and an either high (213±29 g m-2, R. officinalis and E. multiflora) or low (115±17 g m-2, E. arborea) LMA. LMA values were significantly (p≤0.05) correlated with PN (r≥0.68). In the tested species, LMA increased in response to the decrease of the total rainfall during the leaf expansion period. LMA variation was due to the unequal variation of DM and LA in the considered species. LMA is thus a good indicator of evergreen maquis species capability to respond to climate change, in particular to total rainfall decrease in the Mediterranean basin. and L. Gratani, L. Varone.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1764. Longevity and factors influencing photosynthesis in tea leaves
- Creator:
- Raj Kumar, R., Manivel, L., and Marimuthu, S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Camellia assamica ssp. assamica, irradiance, leaf age and insertion, photon flux density, and spectral distribution in canopy
- Language:
- Multiple languages
- Description:
- Quadratic relationship between the age of a tea leaf and the net photosynthetic rate (PN) has been found. A progressive increase in PN was recorded for four months. Then the PN slowly declined, yet even seven-month-old tea leaves sustained a low PN. In a tea shoot, the PN increased from the first leaf onwards. Besides the physiological maturity and proximity, photon flux density (PFD) played an important role in reducing the PN. The tea leaf PN was influenced by cultivation procedures which in turn disrupted the quantum of PFD transmitted through the canopy. and R. Raj Kumar, L. Manivel, S. Marimuthu.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1765. Loretta Vandi, Il manoscritto Oliveriano 1. Storia di un codice boem del XV secolo
- Creator:
- Svobodová, Milada
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- Multiple languages
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1766. Loss of photosynthesis signals a metabolic reprogramming to sustain sugar homeostasis during senescence of green leaves: Role of cell wall hydrolases
- Creator:
- Biswal, B. and Pandey, J. K.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, cell wall hydrolases, senescence, sugar homeostasis, 2, and 581
- Language:
- Multiple languages
- Description:
- Leaf senescence is always associated with decline in photosynthesis, consequently a loss of cellular sugar. On the other hand, execution of senescence program needs energy and leaves, therefore, tend to collect sugars from other sources to sustain energy homeostasis. This sugar reprogramming induced by loss of sugar involves operation of a complex catabolic network. The exact molecular mechanism of induction and regulation of the network, however, is not fully resolved but the current literature available suggests sugar starvation as a signal for induction of several senescence-associated genes including the genes coding for the enzymes for degradation of cellular constituents and their conversion to respiratory sugars. The late expression of genes coding for the cell wall hydrolases and enhancement in the activity of these enzymes late during senescence are indicative of the cell wall polysaccharides as the last source of sugars to sustain energy homeostasis for execution of the senescence program., B. Biswal, J. K. Pandey., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1767. Lotus corniculatus L. response to carbon dioxide concentration and radiation level variations
- Creator:
- Kostopoulou, P. and Karatassiou, M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- světlo, light, elevace, index plasticity, ambient conditions, birdsfoot trefoil, elevation, photosynthetic rate, plasticity index, 2, and 581
- Language:
- Multiple languages
- Description:
- Carbon dioxide concentration and light conditions may greatly vary between mountainous and lowland areas determining the photosynthetic performance of plants species. This paper aimed to evaluate the photosynthetic responses of Lotus corniculatus, growing in a mountain and a lowland grassland, under low and high radiation and CO2 concentration. Net photosynthetic rate, stomatal conductance, transpiration rate, and intercellular CO2 concentration were measured while the water-use efficiency and the ratio of variable to maximal fluorescence were calculated. Photosynthetic response curves to different levels of radiation and intercellular CO2 partial pressure were estimated. Our results showed that high radiation and CO2 concentration enhanced water-use efficiency of plants at both sites, enabling them to use more efficiently the available water reserves under drought conditions. The increase of radiation and CO2 concentration would enhance the photosynthetic performance of the mountainous population of L. corniculatus, which overall seems to express higher phenotypic plasticity., P. Kostopoulou, M. Karatassiou., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1768. Low concentration of bisulfite enhances photosynthesis in tea tree by promoting carboxylation efficiency in leaves
- Creator:
- Yang, W.-J., Chen, H.-F., Zhu, F.-Y., Hu, M.-Q., and Jiang, D.-A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, intercellular CO2 concentration, Melaleuca, photorespiration, photosystem 2, regeneration of ribulose-1,5-bisphosphate, and stomatal conductance
- Language:
- Multiple languages
- Description:
- Tea tree (Melaleuca alternifolia) canopy was sprayed with low concentration of NaHSO3 or mixture of NaHSO3+ KH2PO4. The treatments significantly enhanced net photosynthetic rate (PN), carboxylation efficiency (CE), and the maximum response of PN to intercellular CO2 concentration. The enhancement of PN by foliar application of low concentrations of bisulfite was due to increasing CE relevant to ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase activity and regeneration rate of RuBP depending on ATP formation. and W.-J. Yang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1769. Low concentrations of glycine inhibit photorespiration and enhance the net rate of photosynthesis in Caragana korshinskii
- Creator:
- Kang, T., Wu, H. D., Lu, B. Y., Luo, X. J., Gong, C. M., and Bai, J.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, chlorofylová fluorescence, výměna plynu, pozitivní korelace, stomatální faktor, chlorophyll fluorescence, gas exchange, nonstomatal factor, stomatal factor, 2, and 581
- Language:
- Multiple languages
- Description:
- The inhibition of photorespiration can be used to improve plant carbon fixation. In order to compare the effects of three photorespiration inhibitors [glycine, NaHSO3, and isonicotinyl hydrazide (INH)], photosynthetic parameters of leaves sprayed respectively with these chemicals were examined and their inhibiting efficiency was evaluated in Caragana korshinskii. Our results showed that 5 mM glycine could reduce the photorespiratory rate (PR) effectively, while the net photosynthetic rate (PN), stomatal conductance (gs), and intercellular CO2 concentration (Ci) significantly increased. The ratio of electron flow for ribulose-1,5-bisphosphate (RuBP) carboxylation to RuBP oxygenation was elevated markedly. NaHSO3 and INH could also suppress the PR in some cases, whereas PN was not improved. The glyoxylate content increased considerably after application of low concentrations of glycine. These results suggested that low concentrations of glycine could suppress photorespiration by feed-back inhibition of glyoxylate and enhance photosynthesis by regulating gs, Ci, and the distribution of electron flow in C. korshinskii., T. Kang, H. D. Wu, B. Y. Lu, X. J. Luo, C. M. Gong, J. Bai., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1770. Low concentrations of NaHSO3 increase photosynthesis, biomass, and attenuate photoinhibition in Satsuma mandarin (Citrus unshiu Marc.) plants
- Creator:
- Guo, Y.-P., Hu, M.-J., Zhou, H.-F., Zhang, L.-C., Su, J.-H., Wang, H.-W., and Shen, Y.-G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, delayed light emission, NaHSO3, photophosphorylation, photosynthetic CO2 assmilation, and photosystem 2
- Language:
- Multiple languages
- Description:
- Spraying low concentrated (0.5-5.0 mM) solutions of NaHSO3 on Satsuma mandarin (Citrus unshiu Marc.) leaves resulted in enhancement (maximal about 15 % at 1 mM NaHSO3) of net photosynthetic rate (PN) for 6 d. The potential photochemical efficiency of photosystem 2 (PS2, Fv/Fm) and the quantum yield of PS2 electron transport (ΦPS2) were increased under strong photon flux density (PFD). The slow phase of millisecond delayed light emission (ms-DLE) was increased, showing that the transmembrane proton motive force related to photophosphorylation was enhanced. We also observed that low concentrations of NaHSO3 promoted the production of ATP in irradiated leaves. We suggest that the increase in PN in Satsuma mandarin leaves caused by low concentrations of NaHSO3 solution may have been due to the stimulation of photophosphorylation and, hence, the increase in photochemical efficiency through speeding-up of PS2 electron transport. Photoinhibition of photosynthesis in leaves was modified by NaHSO3 treatment under high PFD. Hence the increase in leaf dry mass seems to be associated with the mitigation of photoinhibition caused by strong PFD. and Y.-P. Guo ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public