Ultraviolet-B Induced Changes in Ultrastructure and D1/D2 Proteins in Cyanobacteria Synechococcus sp. PCC 7942

Sanjay Chauhan, Ritu Pandey, Gauri S. Singhal

Photosynthetica 1997, 35(2):161-167 | DOI: 10.1023/A:1006939003814

Effects of ultraviolet-B (UV-B) irradiation on ultrastructure, total cellular protein, and PS2 proteins D1 and D2 of Synechococcus sp. PCC 7942 cells was studied. The scanning electron micrographs showed UV-B radiation induced bending of the cells. The transmission electron micrographs revealed disorganization and shift in thylakoid lamellar structure to one side of the cell. The cellular phycocyanin/chlorophyll ratio decreased with increasing UV-B treatment and due to this the colour of cells turned light-green. No apparent change in total cellular proteins was evident, but the contents of two major proteins of PS2, D1 and D2, showed decline due to...

Kostkowski, H.J.: Reliable Spectroradiometry

Š. Kubín

Photosynthetica 1997, 35(2):168 | DOI: 10.1023/A:1006943730647

Differences in Cold Inactivation of Phosphoenolpyruvate Carboxylase among C4 Species: The Effect of pH and of Enzyme Concentration

G. Zervoudakis, K. Angelopoulos, G. Salahas, C. D. Georgiou

Photosynthetica 1997, 35(2):169-175 | DOI: 10.1023/A:1006998420652

Among various C4 plants we found a wide range in the level of inactivation of phosphoenolpyruvate carboxylase (PEPC) at low temperature (0 °C). The activity of the 2-fold diluted enzyme in crude leaf extracts after 60 min incubation (compared to zero time incubation) at pH 7.5, remained above 87 % at low temperatures for the species Setaria verticillata, Portulaca oleracea, and Saccharum officinarum, and between 11 and 17 % in the species Cynodon dactylon and Atriplex halimus. The enzyme exhibited intermediate levels of inactivation (42 to 58 %) for the species Amaranthus sp., Zea mays, Salsola kali, and Digitaria sanguinalis. The enzyme activity for...

Cardarelli, F.: Scientific Unit Conversion

Z. Šesták

Photosynthetica 1997, 35(2):176 | DOI: 10.1023/A:1006987512900

High-irradiance Stress and Photochemical Activities of Photosystems 1 and 2 in vivo

K. Veeranjaneyulu, M. Charland, R.M. Leblanc

Photosynthetica 1997, 35(2):177-190 | DOI: 10.1023/A:1006950504723

High-irradiance (HI) stress induced changes in the photosynthetic energy storage (ES) of photosystems 1 (ESPS1) and 2 (ESPS2) were studied with 650 nm modulated radiation in intact sugar maple (Acer saccharum Marsh.) leaves. HI-treatment (420 W m-2, 1 h) caused an inhibition of about 40 % in ESPS2 and an enhancement of about 60 % in ESPS1. The rate of PS1 cyclic electron transport, measured with 705 nm modulated radiation, also increased in HI-treated leaves. There was a clear state 1- state 2 transition in HI-treated leaves. ESPS1 increased significantly and ESPS2 decreased drastically in leaves preadapted to state 1 after HI (600 W m-2, 30 min) treatment....

Heat Emission as a Protective Mechanism against High-irradiance Stress in Sugar Maple Leaves

K. Veeranjaneyulu, R.M. Leblanc

Photosynthetica 1997, 35(2):191-203 | DOI: 10.1023/A:1006902621561

High-irradiance (HI) induced changes in heat emission, fluorescence, and photosynthetic energy storage (EST) of shade grown sugar maple (Acer saccharum Marsh.) saplings were followed using modulated photoacoustic and fluorescence spectroscopic techniques. HI-treatment at 900-4400 µmol m-2 s-1 for 15 min caused an increase in heat emission and a decrease in EST. In some leaves, HI-treatment of 900 µmol m-2 s-1 for 1 min induced a rapid increase in heat emission with a marginal decrease in EST. Parallel to the increase in heat emission, there was a decrease in fluorescence, and this phenomenon was reversible in darkness. Quenching of thermal...

Dey, P.M., Harborne, J.B. (ed.): Plant Biochemistry

N. Wilhelmová

Photosynthetica 1997, 35(2):204 | DOI: 10.1023/A:1006991613809

Changes in Photosynthesis in Inbred Maize Lines with Different Degrees of Chilling Tolerance Grown at Optimum and Suboptimum Temperatures

T. Janda, G. Szalai, J. M. Ducruet, E. Páldi

Photosynthetica 1997, 35(2):205-212 | DOI: 10.1023/A:1006954605631

The effects of growth temperature on changes in net photosynthetic rate (PN) and the chlorophyll fluorescence induction parameter Fv/Fm were investigated after cold stress in inbred maize lines with different degrees of cold tolerance. There was no significant difference between lines grown at optimum temperatures of 25/23 and 20/18 °C as regards PN and Fv/Fm determined at the growth temperature, but these parameters were lower for plants grown at a suboptimum temperature of 15/13 °C. After cold treatment, the decrease in PN was more pronounced in chilling-sensitive lines. The higher the growth temperature was, the more pronounced decrease occurred...

Aluminium Toxicity Modulates Nitrate to Ammonia Reduction

F.C. Lidon, J.C. Ramalho, M.G. Barreiro

Photosynthetica 1997, 35(2):213-222 | DOI: 10.1023/A:1006906722469

Two weeks-old maize (Zea mays cv. XL-72.3) plants were exposed to Al concentrations 0 (Al0), 9 (Al9), 27 (Al27) or 81 (Al81) g m-3 for 20 d in a growth medium with low ionic strength. Thereafter, the Al concentration-dependent interactions on root nitrate uptake, and its subsequent reduction to ammonia in the leaves were investigated. Al concentrations in the roots sharply increased with increasing Al concentrations while root elongation correspondingly decreased. Root fresh and dry masses, acidification capacity, and nitrate and nitrogen contents decreased from Al27 onwards, whereas leaf nitrogen, nitrate, nitrite, and ammonia concentrations decreased...

Alternative Cyanide-sensitive Oxidase Interacting with Photosynthesis in Synechocystis PCC6803. Ancestor of the Terminal Oxidase of Chlororespiration?

C. Büchel, O. Zsíros, G. Garab

Photosynthetica 1997, 35(2):223-231 | DOI: 10.1023/A:1006958706540

Influence of respiration on photosynthesis in Synechocystis PCC6803 was studied by measuring the redox transients of cytochrome f (cyt f) upon excitation of the cells with repetitive single turnover flashes. Upon the addition of KCN the flash-induced oxidation of cyt f was increased and the rereduction of cyt f+ was accelerated. Dependence of these effects on the concentration of KCN clearly demonstrated the existence of two cyanide-sensitive oxidases interacting with photosynthesis: cyt aa3, which was sensitive to low concentrations of cyanide, and an alternative oxidase, which could be suppressed by using ≥1 mM KCN. The interaction between the...

Langhans, R.W., Tibbitts, T.W. (ed.): Plant Growth Chamber Handbook

J. Čatský

Photosynthetica 1997, 35(2):232 | DOI: 10.1023/A:1006995714717

Photosynthesis and Chlorophyll Fluorescence in Two Hybrids of Sorghum under Different Nitrogen and Water Regimes

I. Cechin

Photosynthetica 1997, 35(2):233-240 | DOI: 10.1023/A:1006910823378

In two hybrids of sorghum (Sorghum bicolor Moench.), C51 and C42, high nitrogen concentration (HN) increased net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) of well watered (HW) plants. Water stressing (LW plants) resulted in low PN, gs, and E in both hybrids, but the values were still higher in HN plants as compared to low nitrogen-grown (LN) plants. Intercellular CO2 concentration (Ci) increased in droughted plants. This increase was much higher in LN plants as compared to HN plants. Instantaneous water use efficiency was lower in LN plants as a consequence of a greater effect of water stress on photosynthesis....

The Photosynthetic Efficiency of Some Elite Rice Hybrids and Restorers

M.J. Baig, P. Swain, K.S. Murty

Photosynthetica 1997, 35(2):241-246 | DOI: 10.1023/A:1006962807448

At the vegetative growth stage (40 d), the mean photosynthetic rate (PN) and canopy photosynthesis (PN × LAI) in F1 hybrids and their parents were similar, whereas the maintenance respiration rate (RM) was considerably higher and PN/RM lower in the F1 hybrids than in the parents. Yet at the flowering stage, the hybrids showed higher PN and PN × LAI values, while RM and PN/RM were similar in both. A specific F1 hybrid like IR 62829A×Vajram showed high readings in PN, PN/RM, and PN × LAI at the flowering stage, while IR 62829A×Swarna followed by IR 62829A×Vajram had high values 40 d after planting. The parents Swarna and Vajram, although moderate in...

Photosynthesis of Hedera Canariensis var. Azorica Variegated Leaves as Affected by Ozone

G.F. Soldatini, C. Nali, L. Guidi, G. Lorenzini

Photosynthetica 1997, 35(2):247-253 | DOI: 10.1023/A:1006914924287

A differential response to long-term ozone exposures (50 and 100 mm3 m-3) was observed in the green and white areas of variegated leaves of Hedera canariensis var. azorica L. In green tissue the photosynthetic activity was depressed via a stomatal mechanism, and in white regions no effect was observed. Chlorophyll fluorescence parameters remained unchanged in green portions, whereas in the white ones Fm and Fv/Fm significantly diminished following ozone fumigation.

Albert, T.: Winning the Publications Game

Z. Šesták

Photosynthetica 1997, 35(2):254 | DOI: 10.1023/A:1006939629738

Biochemical and Physiological Response to Salicylic Acid in Relation to the Systemic Acquired Resistance

Amaresh Chandra, R.K. Bhatt

Photosynthetica 1997, 35(2):255-258 | DOI: 10.1023/A:1006966908357

In five genotypes of cowpea (Vigna unguiculata), the influence of salicylic acid (SA) on photosynthetic activity and biochemical constituents including peroxidase activity at the genotypic level was determined. After SA treatment the total free sugar content increased in IFC 8401 and IGFRI 450 genotypes, whereas the content of total leaf soluble proteins decreased significantly in IFC 902. The high chlorophyll (Chl) (a + b) content in IFC 902 showed a good correlation with the net photosynthetic rate (PN), as in this genotype a significant increase in PN was found after the SA treatment.

Photosynthetic Characteristics in Mulberry during Water Stress and Rewatering

S. Ramanjulu, N. Sreenivasalu, S. Giridhara Kumar, C. Sudhakar

Photosynthetica 1997, 35(2):259-263 | DOI: 10.1023/A:1006919009266

Three-month-old plants of mulberry (Morus alba L. cv. Kanva-2) were subjected to a drought stress by withholding water supply. As the leaf water potential (ΨW) was dropping progressively with the severity of treatment and increasing stress duration, the values of leaf area, dry mass accumulation, total chlorophyll (Chl) content, net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) were declined. The photosystem 2 (PS2) photochemical efficiency significantly decreased only at a severe stress treatment. The intercellular CO2 concentration (Ci) remained unaltered during a mild stress, yet it increased under moderate...

The Effect of Irradiance on Hill Reaction Activity of Atrazine-resistant and -susceptible Biotypes of Weeds

M. Körnerová, D. Holá, D. Chodová

Photosynthetica 1997, 35(2):265-268 | DOI: 10.1023/A:1006923226104

Significantly lower Hill reaction activity together with greater sensitivity to photoinhibitory conditions was observed at various irradiances in atrazine-resistant biotypes ofSenecio vulgaris L., Amaranthus retroflexus L., and Poa annua L. compared to the susceptible ones.

The Antenna Size of QB-reducing Photosystem 2 Complexes in Different Fractions of Subchloroplast Particles

D.Y. Kornyeyev

Photosynthetica 1997, 35(2):269-272 | DOI: 10.1023/A:1006975210174

The antenna sizes of QB-reducing photosystem 2 (PS2) complexes in two different fractions of the subchloroplast particles were compared by measuring time corresponding to the second maximum of the first derivative from induction curve of chlorophyll fluorescence as a function of actinic irradiance. The QB-reducing PS2 complexes in the fraction of particles that originated from inner parts of grana thylakoids had smaller antennae than those in the fraction from non-appressed regions of thylakoid membranes.

Diel Acid Fluctuations in C4 Amphibious Grasses

J.E. Keeley

Photosynthetica 1997, 35(2):273-277 | DOI: 10.1023/A:1006927327013

Orcuttieae is a small tribe of C4 grasses endemic to seasonal pools in the southwestern U.S., comprising the basal genus Neostapfia, Tuctoria, and the most derived group, Orcuttia. Growth is initiated underwater, and when pools dry, species undergo a metamorphosis replacing aquatic foliage with terrestrial foliage. O. californica and O. viscida exhibit CAM-like diel fluctuations in acidity in the aquatic foliage. Pulse-chase studies showed that although CO2 was fixed into malic acid in the dark, an overnight chase in the dark revealed that most label was not retained in organic acids, indicating a role other than CAM. Terrestrial foliage exhibited...

Effect of Water Stress on Photosynthesis in Two Mulberry Genotypes with Different drought Tolerance

S. Ramanjulu, N. Sreenivasulu, C. Sudhakar

Photosynthetica 1997, 35(2):279-283 | DOI: 10.1023/A:1006979327921

Three-month-old mulberry (Morus alba L.) cultivars (drought tolerant S13 and drought sensitive S54) were subjected to water stress for 15 d. Water stress decreased the leaf water potential, net photosynthetic rate (PN), and stomatal conductance (gs) in both the cultivars. However, the magnitude of decline was comparatively greater in the sensitive cultivar (S54). Intercellular CO2 concentration (Ci) was unaltered during mild stress, but significantly increased at severe stress in both cultivars. The photosystem 2 activity significantly declined only at a severe stress in both cultivars. The Ci/gs ratio representing the mesophyll efficiency was greater...

Growth and Photosynthetic Characteristics of Ceriops Roxburghiana under NaCl Stress

A. Rajesh, R. Arumugam, V. Venkatesalu

Photosynthetica 1997, 35(2):285-287 | DOI: 10.1023/A:1006983411991

The plant growth, net photosynthetic rate (PN), intercellular CO2 concentration (ci), and dry matter production of Ceriops roxburghiana Arn. were significantly increased with increasing salinity from 0 to 400 mM NaCl. At 600 mM NaCl, shoot and root lengths, and dry mass were significantly depressed with respect to control. Absence of diurnal fluctuation of concentrations of organic acids, and the low activity of phosphoenolpyruvate carboxylase and high activity of ribulose-1,5-bisphosphate carboxylase confirmed the operation of C3 pathway in Ceriops even at increasing salinity.

Bibliography of Reviews and Methods of Photosynthesis - 80

Z. Šesták, J. Čatský

Photosynthetica 1997, 35(2):289-320 | DOI: 10.1023/A:1006935528830