UV-B Induced Alterations in Composition of Thylakoid Membrane and Amino Acids in Leaves of Rhizophora Apiculata Blume

P. Moorthy, K. Kathiresan

Photosynthetica 1997, 35(3):321-328 | DOI: 10.1023/A:1006947831556

Seedlings of Rhizophora apiculata were exposed to UV-B radiation at four doses equivalent to 10, 20, 30, and 40 % ozone depletion. The seedlings irradiated with high doses of UV-B had characteristic decline in contents of specific proteins with molecular masses of 33, 23, and 17 kDa. On the contrary, proteins of 55, 33, 25, 23, and 17 kDa were accumulated in the seedlings exposed to low doses of UV-B. The UV-B, in general, enhanced formation of saturated fatty acids and reduced unsaturated fatty acids, to a maximum extent of 88 and 26 %, respectively. The low dose of UV-B increased content of oleic acid by 9 %, and the high dose reduced it by 34 %....

A Data Base for Scaling up from the Leaf to the Canopy

X. Pan, J.D. Hesketh, M.G. Huck, D.M. Alm

Photosynthetica 1997, 35(3):329-333 | DOI: 10.1023/A:1006999915626

A data base was generated for quantifying effects of thermal time (degree-days) on the appearance of new leaves, the expansion of such leaves to maximum area, their death, the appearance of new internodes below the node associated with such leaves, and the extension of these internodes to maximum length. The data base for a list of crop (agronomic and horticultural), weed, and native Tallgrass Prairie plants has been summarized, with equations for the above events as a function of degree days, with appropriate base temperatures and maximum cut-off temperatures, in a Java applet which is available at a website with the URL <http://th190-50.agn.uiuc.edu>....

Murata, N. (ed.): Molecular Mechanisms of Responses of the Photosynthetic Apparatus to the Environment. Vol. I, II, III, IV.

Z. Šesták

Photosynthetica 1997, 35(3):334 | DOI: 10.1023/A:1006937023803

Differential Responses of Growth and Photosynthesis in Cyamopsis Tetragonoloba L. Grown under Ultraviolet-B and supplemental long-wavelength radiations

K. Lingakumar, G. Kulandaivelu

Photosynthetica 1997, 35(3):335-343 | DOI: 10.1023/A:1006952032464

Cyamopsis tetragonoloba L. seedlings were subjected to continuous ultraviolet (UV)-B radiation for 18 h and post-irradiated with "white light" (WL) and UV-A enhanced fluorescent radiations. UV-B treatment alone reduced plant growth, pigment content, and photosynthetic activities. Supplementation of UV-A promoted the overall seedling growth and enhanced the synthesis of chlorophyll and carotenoids with a relatively high photosystem 1 activity. Post UV-B irradiation under WL failed to photoreactive the UV-B damage whereas a positive photoregulatory effect of UV-A was noticed in electron transport rates and low temperature fluorescence emission spectra.

Koch, G.W., Mooney, A.A. (ed.): Carbon Dioxide and Terrestrial Ecosystems

J. Čatský

Photosynthetica 1997, 35(3):344 | DOI: 10.1023/A:1006989007874

Alterations in Electron Transport Characteristics during Senescence of Cucumis Cotyledonary Leaves. Analysis of the Effects of Inhibitors

J.S.S. Prakash, M.A. Baig, Prasanna Mohanty

Photosynthetica 1997, 35(3):345-352 | DOI: 10.1023/A:1006904116535

Cotyledonary leaves of Cucumis sativus cv. Poinsette exhibited senescence-induced losses in chlorophyll (Chl) and protein contents within three weeks since germination. Chl and protein concentrations in cotyledonary leaves approached maximum on 6th d after germination and they declined to 50 and 41 %, respectively, by the 20th day of growth. Activities of both photosystem (PS) 2 and PS1 decreased by 33 and 31 %, respectively, on the 20th day, compared to the control 6th day. Changes in sensitivity of PS2 to inhibitors like atrazine and dibromothymoquinone and sensitivity of PS1 to KCN accompanied the changes in PS2 and PS1 activities. Hence both the...

Changes in CO2 Exchange Rate, Stomatal Conductance, Activities of Photosystems 1 and 2, and Chloroplast Polypeptide Profile Induced by Simulated Acidic Rain

G. Kumaravelu, M.P. Ramanujam

Photosynthetica 1997, 35(3):353-359 | DOI: 10.1023/A:1006956100605

In seedlings of Vigna radiata (L.) R. Wilczek cultivars ADT-1 and CO-5 exposed to acidic showers (H2SO4 : HNO3 : HCl, 4 : 2 : 1, v/v) of different pH (7.0, 5.5, 4.0, and 2.5) for 10 d, net CO2 uptake and stomatal conductance were reduced. The chlorophyll (Chl) a and b contents were reduced but the carotenoid (Car) content increased. In vivo Chl a fluorescence patterns of both the cultivars were altered. No significant change in photosystem (PS) 1 activity was observed except at pH 2.5 where an inhibition was evident. By contrast, PS2 activities declined rapidly with increasing acidity. The room temperature absorption spectra of isolated chloroplasts...

Satoh, K., Murata, N. (ed.): Stress Responses of Photosynthetic Organisms. Molecular Mechanisms and Molecular Regulations

J. Pospíšilová

Photosynthetica 1997, 35(3):360 | DOI: 10.1023/A:1006993108782

Changes in Ultrastructure of Phaseolus Vulgaris L. Cotyledons Associated with their Modulated Life Span

J. Kutík, N. Wilhelmová, J. Snopek

Photosynthetica 1997, 35(3):361-367 | DOI: 10.1023/A:1006908217443

French bean (Phaseolus vulgaris L.) cotyledons lost most of their reserve substances during several early days of germination and turned green. In cotyledon mesophyll cells of one-week-old seedlings, plastids were represented predominantly by amyloplasts (starch grains) and chloroamyloplasts, and the cells appeared to be metabolically highly active. Cell heterogeneity associated with distance of the cells from cotyledon vascular bundles was evident. Only mesophyll cells near to the bundles were rich in plastids. In two-weeks-old intact bean plants, the cotyledons were yellow and shrunken, and their cells were nearly "empty". The plastids in them were...

Kirkman, J.: Good Style. Writing for Science and Technology

Z. Šesták

Photosynthetica 1997, 35(3):368 | DOI: 10.1023/A:1006941124712

Analysis of Chlorophyll Fluorescence Decays of Isolated Thylakoids in Various Stages of Greening

A. Kowalczyk, A. Waloszek, D. Frackowiak

Photosynthetica 1997, 35(3):369-379 | DOI: 10.1023/A:1006960201513

The decay of chlorophyll (Chl) fluorescence of etiochloroplasts isolated in various stage of greening of cucumber cotyledons was analysed in order to get structural information on a photosynthetic apparatus. Two model decays, multiexponential and stretched exponential, were applied in the analysis. The quality of fit in these two models was different in various stages of chloroplast greening. The two-exponent model did not provide a good fit at early greening stages. To improve the fit it was necessary to introduce an additional third component which became very low at later stages. However, chloroplasts in the early stage of greening could also be...

Smith, G.M.: The Peer-Reviewed Journal: A Comprehensive Guide through the Editorial Process

Z. Šesták

Photosynthetica 1997, 35(3):380 | DOI: 10.1023/A:1006945225621

Relationships among Rhizosphere Oxygen Deficiency, Root Restriction, Photosynthesis, and Growth in Baldcypress (Taxodium Distichum L.) Seedlings

S.R. Pezeshki, M.I. Santos

Photosynthetica 1997, 35(3):381-390 | DOI: 10.1023/A:1006912318352

Seedlings of baldcypress (Taxodium distichum L.) grown in sealed containers containing nutrient solution were subjected to root-zone oxygen deficiency, physical restriction, and the combined stresses in a greenhouse. After six weeks of treatments (Phase I), half of the plants were harvested. The remaining half were allowed to continue (Phase II) under various treatments except plants that had restricted roots were freed thus allowing free expansion of roots into the nutrient solution. Oxygen deficiency and root physical restriction inhibited plant gas exchange parameters. Net photosynthetic rate (PN) was significantly higher in aerated unrestricted...

The Substrate Utilization and Concentration of 14C Photosynthates in Citronella under Fe Deficiency

N.K. Srivastava, A. Misra, S. Sharma

Photosynthetica 1997, 35(3):391-398 | DOI: 10.1023/A:1006964302422

Changes in the utilization pattern of primary substrate, viz. [U-14C] acetate, 14CO2 and [U-14C] saccharose, and the contents of 14C fixation products in photosynthetic metabolites (sugars, amino acids, and organic acids) were determined in Fe-deficient citronella in relation to the essential oil accumulation. There was an overall decrease in photosynthetic efficiency of the Fe-deficient plants as evidenced by lower levels of incorporation into the sugar fraction and essential oil after 14CO2 had been supplied. When acetate and saccharose were fed to the Fe-deficient plants, despite a higher incorporation of label into sugars, amino acids, and organic...

Seasonal Changes in Photosynthesis and Stomatal Conductance of Five Plant Species from a Semiarid Ecosystem

W. Tezara, M.D. Fernández, C. Donoso, A. Herrera

Photosynthetica 1997, 35(3):399-410 | DOI: 10.1023/A:1006916419260

In order to determine whether stomatal closure alone regulates photosynthesis during drought under natural conditions, seasonal changes in leaf gas exchange were studied in plants of five species differing in life form and carbon fixation pathway growing in a thorn scrub in Venezuela. The species were: Ipomoea carnea, Jatropha gossypifolia, (C3 deciduous shrubs), Alternanthera crucis (C4 deciduous herb), and Prosopis juliflora and Capparis odoratissima (evergreen phreatophytic trees). Xylem water potential (Ψ) of all species followed very roughly the precipitation pattern, being more closely governed by soil water content in I. carnea and A. crucis....

Seasonal Variation of Photoinhibition of Photosynthesis in Bark from Populus Tremula L.

K.A. Solhaug, J. Haugen

Photosynthetica 1997, 35(3):411-417 | DOI: 10.1023/A:1006968403331

In the bark of Populus tremula L. photochemical efficiency of photosystem 2 (PS2) determined as Fv/Fm decreased during winter. The strongest reduction was found after cold periods. The degree of reduction depended on irradiance since the lowest levels of Fv/Fm were found on the sun-exposed side of the stem and below thin phellem. Therefore, photoinhibition was partly responsible for the reduction in Fv/Fm. The photochemical efficiency of PS2 recovered in late April about a month before the trees got leaves. In the laboratory, Fv/Fm recovered within about a week under low irradiance at 20 °C. Rapid recovery of photochemical efficiency of PS2 in the...

Wang, W., Gorsuch, J.W., Hughes, J.S. (ed.): Plants for Environmental Studies

J. Čatský

Photosynthetica 1997, 35(3):418 | DOI: 10.1023/A:1006997209691

Photosynthesis of White Clover (Trifolium Repens L.) Germplasms with Contrasting Leaf Size

D.P. Malinowski, D.P. Belesky, J. Fedders

Photosynthetica 1997, 35(3):419-427 | DOI: 10.1023/A:1006920520169

In a growth chamber experiment, we determined net photosynthetic rate (PN) and leaf developmental characteristics of cultivars of a relatively small-, intermediate-, and a large-leaf genotype grown under irradiance of 450-500 µmol(photon) m-2 s-1 (HI), shade [140-160 µmol(photon) m-2 s-1] (LI), and after a shade-to-irradiation (LI >>HI) transfer. Differences in physiological responses of the genotypes were more pronounced in HI and LI>>HI plants than in LI plants. The small- and intermediate-leaf sizes had greater PN in the first measured leaf than the large-leaf type by 70 and 63 % in HI plants, and by 23 and 18 % in LI>>HI...

Characterization of Photosynthetic Apparatus of Pea Chlorophyll Mutants and their Heterotic F1 Hybrids with Standard Genotype (cv. Torsdag)

O.B. Vaishlya, V.G. Ladygin, V.A. Sokolov, G.A. Semenova

Photosynthetica 1997, 35(3):429-443 | DOI: 10.1023/A:1006972504239

In comparison to cv. Torsdag, in leaves of low-productive Pisum sativum L. chlorophyll mutants the decrease in chlorophyll content was caused by the decrease in cell number per unit volume. Qualitative changes in activities of photosystem (PS) 1 in mutant M2004, and quantitative changes of PS1 and PS2 in mutants M2004 and M2014 and in hybrids were also found. However, the activity of ribulose-1,5-bisphosphate carboxylase (RuBPC) in M2014, and those of RuBPC and glyceraldehyde phosphate dehydrogenase in M2004 and hybrids were higher than in cv. Torsdag. The hybrids inherited the normal structure of photosynthetic apparatus of standard genotype in parallel...

Relationship between Photosynthetic Activity and Chlorophyll Content in an Isolated Quercus Ilex L. Tree during the Year

L. Gratani, P. Pesoli, M.F. Crescente

Photosynthetica 1997, 35(3):445-451 | DOI: 10.1023/A:1006924621078

The relationship between chlorophyll (Chl) content and net photosynthetic rate (PN) in an isolated Quercus ilex tree, growing inside Villa Pamphili Park in Rome, was explored. The highest PN was in March, May, and September (10.1 μmol m-2 s-1, maximum rate). PN decreased by 65 % (with respect to the yearly maximum) when leaf temperature reached 34 °C, and by 50 % when leaf temperature was 9 °C. The highest Chl contents were in April, October [1.47 g kg-1 (d.m.), maximum value], and December. The lowest Chl content was found in July (0.78 g kg-1). The decrease of PN in July was in close connection with the decrease of Chl content. On the contrary,...

Source-sink manipulation effects on postanthesis photosynthesis and grain setting on spike in winter wheat

Wang Zhenlin, Yin Yanping, He Mingrong, Cao Hongming

Photosynthetica 1997, 35(3):453-459 | DOI: 10.1023/A:1006976605148

Source-sink manipulation could regulate the net photosynthetic rate (PN) of winter wheat after anthesis, however, the direction and magnitude of the regulation varied with time after anthesis. The PN was significantly increased by source reduction at the initial time of grain filling, but sink reduction had little influence on the PN, which suggested that the sink (spike) limitation did not occur at this time. Source-sink relation markedly affected PN during rapid grain filling. The PN was increased by source reduction and decreased by sink reduction significantly, which indicated that PN was closely associated with the change of source or sink size....

The effects of NaCl and CaCl2 on photosynthesis and growth of alfalfa plants

R.A. Khavari-Nejad, N. Chaparzadeh

Photosynthetica 1997, 35(3):461-466 | DOI: 10.1023/A:1006928721986

The effects of 0, 30, 60, and 90 mM NaCl, and 0 and 5 mM CaCl2 on certain parameters of photosynthesis and growth in alfalfa (Medicago sativa L. cv. Ghara yonjeh) plants were studied. The increasing NaCl concentration in the Hoagland nutrient solution decreased the contents of chlorophylls and the net photosynthetic rate, and increased the rate of respiration (RD) and CO2 compensation concentration in the leaves of treated plants. The contents of carotenoids (Car) were not significantly affected. The addition of 5 mM CaCl2 enhanced the RD and increased the Car contents in treated leaves. With the NaCl concentration in the culture medium increasing,...

Decline in photosynthesis as related to alterations in chloroplast ultrastructure of a cotton leaf during ontogeny

Bhaskar Rao Bondada, D.M. Oosterhuis

Photosynthetica 1997, 35(3):467-471 | DOI: 10.1023/A:1006980806057

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...

Effect of UV radiation on pigments of the Antarctic macroalga Leptosomia simplex L.

G. Döhler

Photosynthetica 1997, 35(3):473-476 | DOI: 10.1023/A:1006932922895

Impact of UV-A and UV-B radiation on pattern of pigments of the Antarctic macroalga Leptosomia simplex L. was studied during the Polarstern cruise (ANT XII/2) 1994/95 under controlled laboratory conditions. An 8 h exposure to UV-A of 17.6 W m-2 led usually to an increase of carotenoid contents, but to a decrease in contents of chlorophyllide (Chlide) a and chlorophyll (Chl) a. UV-B irradiation (300-320 nm) caused a decrease in contents of Chlide a, lutein, and zeaxanthin, but an increase in contents of Chl a and carotenes. Enhancement of carotenoid contents was attributed to a protection of the photosynthetic apparatus. UV effects on the 15N-ammonium...

Photosystem 2 photoinactivation and repair in the Scenedesmus cells treated with herbicides DCMU and BNT and exposed to high irradiance

J. Komenda

Photosynthetica 1997, 35(3):477-480 | DOI: 10.1023/A:1006984906965

Changes in fluorescence parameters observed during irradiation of the Scenedesmus cells showed that photosystem 2 (PS2) photoinactivation in cells treated with phenolic PS2 inhibitor 2-bromo-3-methyl-6-isopropyl-4-nitrophenol (BNT) was significantly accelerated in comparison with control and DCMU-treated cells. Moreover, a negligible difference in the rate of PS2 photoinactivation in the absence and presence of chloramphenicol indicated that both DCMU and BNT blocked the PS2 repair process.