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2062. Determinant of photosynthetic capacity in rice leaves under ambient air conditions
- Creator:
- Zhang, D.-Y., Wang, X.-H., Chen, Y., and Xu, D.-Q.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carboxylation efficiency, flag leaf, intercellular CO2 concentration, leaf position, net photosynthetic rate, Oryza, and stomatal conductance
- Language:
- Multiple languages
- Description:
- At the grain-filling stage, net photosynthetic rate (PN), stomatal conductance (gs), and ribulose-1,5-bisphosphate carboxylation efficiency (CE) were correlated in order to find the determinant of photosynthetic capacity in rice leaves. For a flag leaf, PN in leaf middle region was higher than in its upper region, and leaf basal region had the lowest PN value. The differences in gs and CE were similar. PN, gs, and CE gradually declined from upper to basal leaves, showing a leaf position gradient. The correlation coefficient between PN and CE was much higher than that between PN and gs in both cases, and PN was negatively correlated with intercellular CO2 concentration (Ci). Hence the carboxylation activity or activated amount of ribulose-1,5-bisphosphate carboxylase/oxygenase rather than gs was the determinant of the photosynthetic capacity in rice leaves. In addition, in flag leaves of different tillers PN was positively correlated with gs, but negatively correlated with Ci. Thus gs is not the determinant of the photosynthetic capacity in rice leaves. and D.-Y. Zhang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2063. Determination of PS I oligomerisation in various cyanobacterial strains and mutants by non-invasive methods
- Creator:
- Zakar, T., Kovacs, L., Vajravel, S., Herman, E., Kis, M., Laczko-Dobos, H., and Gombos, Z.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- karotenoidy, carotenoids, pigment-protein interactions, temperature stress, xanthophylls, 2, and 581
- Language:
- Multiple languages
- Description:
- PSI trimer to monomer ratio in intact cyanobacterial cells and isolated thylakoids was analysed by two noninvasive, in vivo methods; low-temperature fluorescence emission and circular dichroism spectroscopy. We measured fluorescence emission spectra of cells upon chlorophyll (Chl, 436 nm) excitation. All three species - Synechocystis sp. PCC 6803, Anabaena sp. PCC 7120, and Spirulina platensis - showed shifted Chl peak, indicating they have different spectral properties. CD spectroscopy revealed the highest intensity at 515 nm (PSI peak) in Spirulina platensis cells, which may originate from PSI multi-oligomerisation. The most sensitive response to heat treatment in this strain was the oligomerisation of PSI RCs. PSI dimers and tetramers in Anabaena cells showed smaller changes of the CD signal upon the heat treatment compared to that of Synechocystis WT. The lack of γ-linolenic acid affected the filament morphology by the loss of the spiral shape and the PSI monomerisation in Spirulina I22., T. Zakar, L. Kovacs, S. Vajravel, E. Herman, M. Kis, H. Laczko-Dobos, Z. Gombos., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2064. Detrimental effects of fluctuating high CO2 concentrations on peppers
- Creator:
- Peňuelas, J., Biel, C., Savé, R., and Estiarte, M.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Capsicum annuum L., water supply, stomatal conductance, specific leaf mass, root/shoot ratio, respiration rate, plant height, fruit, dry mass, and chlorophyll
- Language:
- Multiple languages
- Description:
- Plants of pepper (Capsicum amuum L.) were grown in controlled environment chambers at ambient (360 pmol mol"*) and fluctuating pulse-enriched CO2 concentrations (700 pmol mol"* daily average, ranging from 500 to 3500 pmol mol"* = ECO2) under two water regimes. A decrease in plant growth and yield together with frequent visual injuries was found in plants growing under ECO2. Root/shoot ratio was greater, chlorophyll concentration and respiration rates were lower, and stomatal conductance and relative importance of alternativě pathway respiration were higher under ECO2. The negative effects of ECO2 were more intense under high water availability. The symptoms produced by ECO2 were similar to those of resource limitation, and were alleviated with increased nutrient supply. Constant elevated CO2 concentrations (700 pmol mol"*) increased pepper production and did not produce any of the injuries described for this erratic ECO2 treatment. Thus, it is probably the erratic nátuře of the CO2 concentration and not the gas itself that was causing the injiuy.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2065. Deutsch, A., Howard, J., Falcke, M., Zimmermann, W. (ed.): Function and regulation of cellular systems
- Creator:
- Nováková, O.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- biological research
- Language:
- Multiple languages
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2066. Devadesát let Pavla Spunara (* 21. května 1928, Praha)
- Creator:
- Hlaváček, Ivan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- scientific research, medievalistic studies, and historians
- Language:
- Multiple languages
- Description:
- Za redakci a všechny žáky a přátele, blízké i vzdálené Ivan Hlaváček
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
2067. Development of chloroplast in dark-grown wheat seedlings irradiated at elevated temperature
- Creator:
- Singh, A. K. and Singhal, G. S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, chlorophyll, nucleic acids, photosystem 2, proteins, and Triticum aestivum
- Language:
- Multiple languages
- Description:
- Elevated temperature inhibited the accumulation of chlorophyll and photosynthetic proteins, and the development of photochemical activity, however, carotenoids continued to accumulate. Signal transduction pathway involved in protochlorophyllide oxidoreductase was unaffected by elevated temperature of 38°C. Two-dimensional gel electrophoresis of stroma proteins showed similar patterns in the dark-grown seedlings and seedlings irradiated at elevated temperature, although some low molecular mass proteins accumulated at 38°C. In contrast, seedlings irradiated at 25°C showed complex pattern of proteins. Hence the development of chloroplast and its associated functions during irradiation of etiolated seedlings are inhibited by elevated temperature. and A. K. Singh, G. S. Singhal.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2068. Development of models for estimating leaf chlorophyll and nitrogen contents in tree species with respect to seasonal changes
- Creator:
- Mizusaki, D., Umeki, K., and Honjo, T.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, Agriexpert PPW-3000, Bayesian statistics, evergreen broad-leaved species, leaf chlorophyll content, leaf nitrogen, optical meter, seasonal change, SPAD-502, 2, and 581
- Language:
- Multiple languages
- Description:
- Models were developed to estimate nondestructively chlorophyll (Chl) content per unit of leaf area (Chlarea) and nitrogen content per unit of leaf area (Narea) using readings of two optical meters for five warm-temperate, evergreen, broadleaved tree species (Castanopsis sieboldii, Cinnamomum tenuifolium, Eurya japonica, Machilus thunbergii, and Neolitsea sericea). It was determined whether models should be adjusted seasonally. Readings (were obtained six times during a year period and Chlarea and Narea were determined using destructive methods. Bayesian inference was used to estimate parameters of models that related optical meter readings to Chlarea or Narea for each species. Deviance information criterion values were used to select the best among models, including the models with seasonal adjustment. The selected models were species-specific and predicted Chlarea accurately (R2 = 0.93-0.96). The best model included parameters with seasonal adjustments for one out of five species. Model-based estimates of Narea were not as accurate as those for Chlarea, but they were still adequate (R2 = 0.64-0.82). For all species studied, the best models did not include parameters with seasonal adjustments. The estimation methods used in this study were rapid and nondestructive; thus, they could be used to assess a function of many leaves and/or repeatedly on individual leaves in the field. and D. Mizusaki, K. Umeki, T. Honjo.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2069. Development of photosynthetic electron transport reactions under the influence of phytohormones during greening of cotyledons of Brassica juncea
- Creator:
- Sant Saroop, Thaker, V.S., Chanda, S.V., Vainshnav, P.P., and Singh, Y.D.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- In greening mustard cotyledons, both photosystems (PS) 1 and 2 were significantly promoted by addition of gibberelic acid (GA) at low concentrations, i.e. upto 10 μΜ, while at higher concentrations no significant changes were recorded. PS2 activity in kinetin (KN) treated seedlings was promoted at concentrations upto 5 μΜ KN, while it showed a slight inhibition at higher concentrations. No significant change in PS1 activity was observed when compared to controls. Other particular photosynthetic electron transport reactions were also increased by GA and KN. KN03 showed concentration-dependent effects on photosynthetic electron transport reactions.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2070. Development of photosystems 2 and 1 during leaf growth in grapevine seedlings probed by chlorophyll a fluorescence transient and 820 nm transmission in vivo
- Creator:
- Jiang, C.-D., Shi, L., Gao, H.-Y., Schansker, G., Toth, S. Z., and Strasser, R. J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- irradiance, leaf age, oxygen evolving complex, performance index, reaction centre, and Vitis
- Language:
- Multiple languages
- Description:
- Chlorophyll (Chl) a fluorescence transient and 820-nm transmission kinetic were investigated to explore the development of photosynthetic apparatus in grapevine leaves from emergence to full expansion. In this study, all leaves at various developing stages exhibited typical Chl a fluorescence transient. In newly initiating leaves, the maximum quantum yield of primary photochemistry (ϕP0) was slightly lower (<10 %) than that in fully expanded leaves. Nevertheless, the fluorescence rise from O to J step was clearly speeded up in young leaves compared with that in fully expanded leaves. Additionally, a distinct K step appeared in young leaves at high irradiances. With leaf development, the efficiency that a trapped exciton can move an electron into the electron transport chain further than QA - (Ψ0), the quantum yield of electron transport beyond QA (ϕE0), electron transport flux per excited cross section (ET0/CS0), the amount of active photosystem (PS) 2 reaction centres per excited cross section (RC/CS0), and the performance index on cross section basis (PICS) increased gradually and rapidly. Young leaves had strikingly lower amplitude of transmission at 820 nm. A linear relationship between Ψ0 and the transmission at 820 nm (I30/I0) was evident. Based on these data, we suggest that (1) the primary photochemistry of PS2 may be not the limiting step of the photosynthetic capacity during leaf growth under natural irradiance; (2) oxygen evolving complex (OEC) might be not fully connected to PS2 at the beginning of leaf growth; (3) though there are a few functional PS1 and PS2 at the early stages of leaf development, they match perfectly. and C.-D. Jiang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public