Interactions of Chlorophyll and Polypeptide Mixture with Bacterial Reaction Centres

H. Enomoto, S. Takeda, C. Nakamura, J. Miyake, A. Ptak, A. Dudkowiak, D. Frackowiak

Photosynthetica 2000, 38(1):1-6 | DOI: 10.1023/A:1026723303078

In aqueous solutions of chlorophyll (Chl) a with synthesized polypeptides, at high ratios of Chl to polypeptides (about 75-150 µM to 500 µM) clusters of polypeptides and pigment molecules were formed. The main absorption maxima of more than one formed cluster were located at about 500 nm (Soret band) and in the region of 720-806 nm (red band). The formation of these clusters was fairly slow (some hours) at room temperature and even slower at 4 °C. The rate of cluster formation increased with the increase in Chl concentration. The addition of the even low amount of reaction centres (RCs), separated from the purple bacteria Rhodobacter...

Drought Effects on Membrane Lipids and Photosynthetic Activity in Different Peanut Cultivars

J.A. Lauriano, F.C. Lidon, C.A. Carvalho, P.S. Campos, M. do Céu Matos

Photosynthetica 2000, 38(1):7-12 | DOI: 10.1023/A:1026775319916

The effects of drought on thylakoid acyl lipid composition, photosynthetic capacity (P _max), and electrolyte lekage were evaluated in two-months-old peanut cultivars (57-422, 73-30, GC 8-35) growing in a glasshouse. For lipid studies, plants were submitted to three treatments by withholding irrigation: control (C), mild water stress (S1), and severe water stress (S2). Concerning membrane and photosynthetic capacity stability, drought was imposed by polyethylene glycol (PEG 600). In the cv. 73-30 a sharp decrease in the content of thylakoid acyl lipids was observed, already under S1 conditions, whereas cv. 57-422 was strongly affected...

Effects of Season, Needle Age, and Elevated Atmospheric CO₂ on Chlorophyll Fluorescence Parameters and Needle Nitrogen Concentration in Scots Pine (Pinus sylvestris)

B. Gielen, M.E. Jach, R. Ceulemans

Photosynthetica 2000, 38(1):13-21 | DOI: 10.1023/A:1026727404895

Six-year-old Scots pine (Pinus sylvestris L.) seedlings were grown in open top chambers (OTCs) at ambient (AC) or elevated (ambient + 400 µmol mol^-1; EC) CO₂ concentration for three years (1996-1998). Chlorophyll (Chl) a fluorescence of current and one-year-old needles was measured in the field at two-weekly intervals in the period July-October 1998. In addition, Chl, carbon (C), and nitrogen (N) concentrations in both needle age classes were determined monthly during the same period. Chl fluorescence parameters were not significantly affected by EC, suggesting there was no response of the light reactions and...

Benzing, D.H.: Bromeliaceae: Profile of an Adaptive Radiation

J. Čatský

Photosynthetica 2000, 38(1):22 | DOI: 10.1023/A:1026772713981

Modulation of Phosphoenolpyruvate Carboxylase Phosphorylation in Leaves of Amaranthus hypochondriacus, a NAD-ME Type of C₄ Plant

K. Parvathi, J. Gayathri, G.B. Maralihalli, A.S. Bhagwat, A.S. Raghavendra

Photosynthetica 2000, 38(1):23-28 | DOI: 10.1023/A:1026783521733

PEP carboxylase (PEPC) in leaves of C₄ plants is activated by phosphorylation of enzyme by a PEPC-protein kinase (PEPC-PK). We reevaluated the pattern of PEPC phosphorylation in leaf extracts of Amaranthus hypochondriacus. It was dependent on Ca²⁺, the optimum concentration of which for stimulation was 10 mM. The extent of stimulation was inhibited by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), a Ca²⁺ chelator. The inhibition by BAPTA was relieved by the addition of Ca²⁺ but not by the addition of Mg²⁺. The stimulation by Ca²⁺ of PEPC phosphorylation was...

Analysis of Some Barley Chlorophyll Mutants and Their Response to Temperature Stress

E. Gálová, B. Böhmová, A. Ševčovičová

Photosynthetica 2000, 38(1):29-35 | DOI: 10.1023/A:1026735605804

Six barley chlorophyll (Chl) mutants, viridis, flavoviridis, chlorina, xanhta, lutea, and albina, differed in the contents of Chl (a+b) and carotenoids (Cars). In accordance with their Chl-deficient phenotype, the Chl a and b and Car contents of mutants decreased from viridis to albina, only xantha had the same or even higher concentration of Cars as the wild type plant. The albina mutant completely lacked and xantha had a significantly reduced photosynthetic activity. We found quantitative differences in protein contents between wild type and mutant...

Tuba, Z., Nagy, Z., Szente, K., Raschi, A. (ed.): Grassland Ecology and Ecophysiology Under Elevated Atmospheric CO₂ and Temperature

Z. Šesták

Photosynthetica 2000, 38(1):36 | DOI: 10.1023/A:1026724830820

Leigh, R.A., Sanders, D. (ed.): The Plant Vacuole

J. Albrechtová

Photosynthetica 2000, 38(1):36 | DOI: 10.1023/A:1026776814890

Chlorophyll Synthesis Retardation and Ultrastructural Alterations to Solanum tuberosum Chloroplasts in Solanum nigrum Cells

K.A. Fayez, A.M. Hassanein

Photosynthetica 2000, 38(1):37-44 | DOI: 10.1023/A:1026787622642

Photosynthetic pigment contents of the second sexual generation of a cybrid plant (C-18-1) resulting from Solanum nigrum genome and Solanum tuberosum plastome were compared to those of the original (S. nigrum). Chloroplast ultrastructure alterations among S. tuberosum, cybrid, and S. nigrum were also studied. Leaf segments of both the cybrid and S. nigrum plants were cultured on shoot induction medium [B5 supplemented with 0.56 g m^-3 benzylaminopurine (BAP)] for one week in light, to induce adventitious bud formation. These leaf segments were then placed in darkness for 5 weeks to form a white shoot....

Purification and Stability during Storage of Phoshoenolpyruvate Carboxylase from Leaves of Amaranthus hypochondriacus, a NAD-ME Type C₄ Plant

J. Gayathri, K. Parvathi, A.S. Raghavendra

Photosynthetica 2000, 38(1):45-52 | DOI: 10.1023/A:1026739806712

A traditional method is reported for purification of phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) from leaves of Amaranthus hypochondriacus L. with a high yield of 50 %, 135-fold purification, and specific activity of 900 mmol kg^-1(protein) s^-1. PEPC was purified from light-adapted leaves of A. hypochondriacus, involving 40-60 % ammonium sulphate fractionation, followed by chromatography on columns of DEAE-Sepharose, hydroxylapatite (HAP), and Seralose 6-B. The enzyme appeared as a single band on 10 % SDS-PAGE, with a molecular mass of about 100 kDa. Kinetic studies with purified enzyme...

A Cheap Chlorophyll a Fluorescence Imaging System

P. Lootens, P. Vandecasteele

Photosynthetica 2000, 38(1):53-56 | DOI: 10.1023/A:1026791823551

A cheap chlorophyll (Chl) a fluorescence imaging system was developed for measuring leaf areas of 30×45 cm. Uniform saturating irradiances were created using CuSO₄ filtered radiation from stroboscopes. The system was tested using maize leaves treated with diuron. Comparison was made with a small-area-measuring pulse amplified modulation Chl fluorometer.

Short- versus Long-Term Effects of Elevated CO₂ on Night-Time Respiration of Needles of Scots Pine (Pinus sylvestris L.)

M.E. Jach, R. Ceulemans

Photosynthetica 2000, 38(1):57-67 | DOI: 10.1023/A:1026743907621

Dark respiration rate in the night (R _D) was measured in five-year-old Scots pine (Pinus sylvestris L.) trees grown for two years under ambient (AC) and elevated (AC + 400 µmol mol^-1 = EC) CO₂ concentrations in open top chambers. Two needle age classes (i.e., current-year and one-year-old) were measured at AC and EC in both AC- and EC-grown pines. Additionally different chemical characteristics were determined on the needles, such as nitrogen (N), carbon (C), starch, and soluble sugar concentrations as well as specific leaf area. The direct, short-term and indirect, long-term effects of EC...

Tagu, D. (ed.): Principes des techniques de biologie moléculaire

O. Navrátil

Photosynthetica 2000, 38(1):68 | DOI: 10.1023/A:1026780915798

Controlled Environment Chambers for Investigating Tree Response to Elevated CO₂ and Temperature Under Boreal Conditions

S. Kellomäki, Kai-Yun Wang, M. Lemettinen

Photosynthetica 2000, 38(1):69-81 | DOI: 10.1023/A:1026795924459

A closed CO₂ and temperature-controlled, long-term chamber system has been developed and set up in a typical boreal forest of Scots pine (Pinus sylvestris L.) near the Mekrijärvi Research Station (62°47'N, 30°58'E, 145 m above sea level) belonging to the University of Joensuu, Finland. The main objectives of the experiment were to provide a means of assessing the medium to long-term effects of elevated atmospheric CO₂ concentration (EC) and temperature (ET) on photosynthesis, respiration, growth, and biomass at the whole-tree level and to measure instantaneous whole-system CO₂ exchange. The system consists of...

Gräber, P., Milazzo, G. (ed.): Bioenergetics

Z. Šesták

Photosynthetica 2000, 38(1):82 | DOI: 10.1023/A:1026728931728

Contrasting Effects of Carbon Dioxide and Irradiance on the Acclimation of Photosynthesis in Developing Soybean Leaves

J.A. Bunce

Photosynthetica 2000, 38(1):83-89 | DOI: 10.1023/A:1026748008530

Leaves developed at high irradiance (I) often have higher photosynthetic capacity than those developed at low I, while leaves developed at elevated CO₂ concentration [CO₂] often have reduced photosynthetic capacity compared with leaves developed at lower [CO₂]. Because both high I and elevated [CO₂] stimulate photosynthesis of developing leaves, their contrasting effects on photosynthetic capacity at maturity suggest that the extra photosynthate may be utilized differently depending on whether I or [CO₂] stimulates photosynthesis. These experiments were designed to test whether...

Raschi, A., Miglietta, F., Tognetti, R., van Garningen, P.R. (ed.): Plant Responses to Elevated CO₂. Evidence from Natural Springs

J. Čatský

Photosynthetica 2000, 38(1):90 | DOI: 10.1023/A:1026733032637

Interactive Effects of Sulphur Dioxide and Mineral Nutrient Supply on Photosynthetic Characteristics and Yield in Four Wheat Cultivars

M. Verma, M. Agrawal, S.S. Deepak

Photosynthetica 2000, 38(1):91-96 | DOI: 10.1023/A:1026700109438

Field experiments were conducted on four cultivars of wheat (Triticum aestivum L.) to examine the variability in cultivar response to sulphur dioxide (SO₂) under different concentrations of mineral nutrients. Thirty-days-old plants were exposed for 8 weeks to 390±20 µg m^-3 (0.15 ppm) SO₂ for 4 h per day, 5 d per week. Decline in net photosynthetic rate, contents of pigments and nitrogen, biomass and grain yield of each cultivars were due to SO₂ at all the nutrient concentrations studied. However, the magnitude of reduction was higher in plants grown without nutrient application. On the...

Photosynthesis in Drought-Adapted Cassava

P. A. Calatayud, E. Llovera, J.F. Bois, T. Lamaze

Photosynthetica 2000, 38(1):97-104 | DOI: 10.1023/A:1026704226276

After 45 d of limited water supply, cassava (Manihot esculenta Crantz) exhibited pronounced reduction in shoot growth, high leaf fall, and decreased stomatal conductance. However, the water status of the remaining leaves was unaffected. This was combined with an amplified heliotropic response and drooping which minimises radiant energy interception at mid-day, suggesting that leaves are sensitive to high irradiance (I). In well-irrigated plants, CO₂-saturated oxygen evolution and net photosynthetic rate (P _N) in air were markedly higher (5-fold) in young (expanding) leaves than in mature leaves. Water limitation...

Genotype Variability in Photosynthetic Characteristics in Finger Millet

Desiraju Subrahmanyam

Photosynthetica 2000, 38(1):105-109 | DOI: 10.1023/A:1026756210347

High variability in leaf gas exchange and related traits were found in 30 genotypes of field grown finger millet. The variability in carbon exchange rate per unit leaf area (P _N) can be partly attributed to the differences in the stomatal conductance (g_s) and area leaf mass (ALM). The P _N was positively correlated with total dry matter (TDM). However, no relationship between P _N and seed yield was found. The leaf area showed a positive and significant correlation with total biomass. None of the other gas-exchange traits had significant relationship either with TDM or with seed yield....

Estimation of Primary Productivity by Chlorophyll a in vivo Fluorescence in Freshwater Phytoplankton

M. Gilbert, A. Domin, A. Becker, C. Wilhelm

Photosynthetica 2000, 38(1):111-126 | DOI: 10.1023/A:1026708327185

Primary productivity in marine waters is widely estimated by the measurements of ¹⁴C incorporation, the underwater light climate, and the absorption spectra of phytoplankton. In bio-optical models the quantum efficiency of carbon fixation derived from ¹⁴C incorporation rates, the photosynthetically absorbed radiation derived from the underwater light climate, and the phytoplankton absorption spectra are used to calculate time- and depth-integrated primary productivity. Due to the increased sensitivity of commercially available fluorometers, chlorophyll a in vivo fluorescence became a new tool to assess the photosynthetic...

Photosynthetic Thermotolerance is Quantitatively and Positively Correlated with Production of Specific Heat-shock Proteins Among Nine Genotypes of Lycopersicon (Tomato)

P.J. Preczewski, S.A. Heckathorn, C.A. Downs, J.S. Coleman

Photosynthetica 2000, 38(1):127-134 | DOI: 10.1023/A:1026760311255

We recently showed that the chloroplast small heat-shock protein (herein referred to as chlp Hsp24) protects photosystem 2 (PS2) during heat stress, and phenotypic variation in production of chlp Hsp24 is positively related to PS2 thermotolerance. However, the importance of chlp Hsp24 or other Hsps to other aspects of photosynthesis and overall photosynthetic thermotolerance is unknown. To begin investigating this and the importance of genetic variation in Hsp production to photosynthetic thermotolerance, the production of several prominent Hsps and photosynthetic thermotolerance were quantified in nine genotypes of Lycopersicon, and then the...

Effect of Indol-3-yl Acetic Acid on Photosynthetic Characteristics of Wheat Flag Leaf During Grain Filling

H.S. Aldesuquy

Photosynthetica 2000, 38(1):135-141 | DOI: 10.1023/A:1026712428094

Area and fresh and dry masses of flag leaf show two phases of development during grain filling in Triticum aestivum. The initial large increase in leaf size is mainly due to water intake. Contents of chlorophylls and carotenoids, reducing sugars, and sucrose, Hill reaction rate, and photosynthetic activity increased during leaf growth, but a noticeable decline in these parameters followed throughout leaf senescence. The maximum accumulation of polysaccharides and proteins occurred at the beginning of grain set, but a continuous decline in their absolute values was manifested during grain filling. Grain priming with indol-3-yl acetic acid (IAA)...

Linear Dichroism, Fluorescence Polarization, and Path of the Thermal Deactivation of Excited Cyanobacterial (Synechococcus Elongatus) Photosystem 1 Immobilized and Oriented in Polymer Films

G.E. Białek-Bylka, D. Sofrová, J. Szurkowski, R. Skwarek, B. Sopko, H. Manikowski

Photosynthetica 2000, 38(1):143-148 | DOI: 10.1023/A:1026764412164

Pigment-protein complexes enriched in photosystem 1 (PS1) and, for comparison, enriched in photosystem 2 (PS2) were isolated from the cyanobacterium Synechococcus elongatus Nag. f. thermalis Geitl. They were immobilized and oriented in the polyvinyl alcohol (PVA) films, and studied by linear dichroism (LD), fluorescence polarization (FP), photoacoustic spectroscopy (PAS), and polarized photoacoustic spectroscopy (PAS_|| and PAS_⊥). The LD signal of β-carotene in the region with maximum at 500 nm was positive in the PS1 complex. The maximum value of fluorescence polarization (FP) in the measured photosynthetic...

Foliar Spraying with Zineb Increases Fruit Productivity and Alleviates Oxidative Stress in Two Tomato Cultivars

Á. Calatayud, E. Barreno

Photosynthetica 2000, 38(1):149-154 | DOI: 10.1023/A:1026716529002

The effects of foliar spraying of the dithiocarbamate zineb on two cultivars of tomato grown in the field in a site with high ozone concentrations were studied by means of biomass assessment, antioxidant enzyme assays, lipid peroxidation, and chlorophyll fluorescence measurements. Zineb prevented the peroxidation of membrane lipids and decreased the activity of scavenging enzymes, which suggests that plants sprayed with zineb are subjected to lower oxidative stress than controls. The beneficial effects of zineb protection is the utilization of a larger fraction of absorbed radiant energy in photosynthesis and a larger fruit yield in plants of both cultivars.

Discrimination Against ¹³CO₂ in Leaves, Pod Walls, and Seeds of Water-stressed Chickpea

M.H. Behboudian, Q. Ma, N.C. Turner, J.A. Palta

Photosynthetica 2000, 38(1):155-157 | DOI: 10.1023/A:1026768513073

The rate of photosynthesis (P _N) in leaves and pods as well as carbon isotope content in leaves, pod walls, and seeds was measured in well-watered (WW) and water-stressed (WS) chickpea plants. The P _N, on an area basis, was negligible in pods compared to leaves and was reduced by water stress (by 26%) only in leaves. WS pod walls and seeds discriminated less against ¹³CO₂ than did the controls. This response was not observed for leaves as is usually the case. Pod walls and seeds discriminated less against ¹³CO₂ than did leaves in both WW and WS plants. Measurement of carbon...

Size and Power of Chlorophyll a Molecule

P. Strebeyko

Photosynthetica 2000, 38(1):159-160 | DOI: 10.1023/A:1026720729911

On the basis of literature and my calculations it was established that a chlorophyll (Chl) particle anchored with a phytol chain to the thylakoid membrane takes up about 1 nm² of the surface area. At an irradiance of 287 W m^-2 the leaves of cabbage seedlings become saturated with photosynthetically active radiation (PAR) thus reaching the maximum photosynthetic rate of 100 µg(C) m^-2 s^-1, that is 5 CO₂ molecules per 1 nm² per second, and the maximum power with which the Chl particle supplies the process of photosynthesis is 15 aJ.