Gas Exchange and Chlorophyll Fluorescence Response to Simulated Rainfall in Hedysarum fruticosum var. mongolicum

S.L. Niu, L.H. Li, G.M. Jiang, L.M. Gao, Y.G. Li, Y. Peng, M.Z. Liu

Photosynthetica 2004, 42(1):1-6 | DOI: 10.1023/B:PHOT.0000040562.34339.b3

The response of gas exchange and chlorophyll fluorescence along with changes in simulated rainfall were studied in water stressed plants Hedysarum fruticosum var. mongolicum (H.f.m.). Net photosynthetic rate (P_N), stomatal conductance (gs), leaf water potential (Ψ_leaf), and apparent carboxylation efficiency (P_N/C_i) were significantly increased with the increase of rainfall. However, they did not change synchronously. The complete recovery of both P_N and P_N/C_i appeared 3 d after watering while g_s...

Photoinhibition of Photosynthesis in Sun and Shade Grown Leaves of Grapevine (Vitis vinifera L.)

M. Bertamini, K. Muthuchelian, N. Nedunchezhian

Photosynthetica 2004, 42(1):7-14 | DOI: 10.1023/B:PHOT.0000040563.64215.63

The degree of photoinhibition of sun and shade grown leaves of grapevine was determined by means of the ratio of variable to maximum chlorophyll (Chl) fluorescence (F_v/F_m) and electron transport measurements. The potential efficiency of photosystem 2 (PS2), F_v/F_m, markedly declined under high irradiance (HI) in shade leaves with less than 10 % of F₀ level. In contrast, F_v/F_m ratio declined with about 20 % increase of F₀ level in sun leaves. In isolated thylakoids, the rate of whole chain and PS2 activity in HI shade and sun leaves was decreased by about 60 and 40...

Activity of Photosystem 2, Lipid Peroxidation, and the Enzymatic Antioxidant Protective System in Heat Shocked Barley Seedlings

F. El-Shintinawy, M.K.H. Ebrahim, N. Sewelam, M.N. El-Shourbagy

Photosynthetica 2004, 42(1):15-21 | DOI: 10.1023/B:PHOT.0000040564.79874.42

The impact of heat shock on minimising the activity of photosystem 2 (PS2) initiating high lipid peroxidation (POL) level and consequently changes in the enzymatic-antioxidant protective system was studied in seedlings of two Egyptian cultivars of barley (Giza 124 and 125). Heat doses (35 and 45 °C for 2, 4, 6, and 8 h) decreased chlorophyll (Chl) contents coupled with an increase in Chl a/b ratio, diminished Hill reaction activity, and quenched Chl a fluorescence emission spectra. These parameters reflect the disturbance of the structure, composition, and function of the photosynthetic apparatus as well as the activity of PS2. POL level,...

Nölting, B.: Methods in Modern Biophysics

D. Kaftan, F. Adamec

Photosynthetica 2004, 42(1):22 | DOI: 10.1023/B:PHOT.0000040640.45406.22

Response of Spinach Leaves (Spinacia oleracea L.) to Ozone Measured by Gas Exchange, Chlorophyll a Fluorescence, Antioxidant Systems, and Lipid Peroxidation

A. Calatayud, D.J. Iglesias, M. Talón, E. Barreno

Photosynthetica 2004, 42(1):23-29 | DOI: 10.1023/B:PHOT.0000040565.53844.c6

Spinach (Spinacia oleracea L. cv. Clermont) leaves grown in open-top chambers and exposed to three different concentrations of ozone were measured for gas exchange, chlorophyll a fluorescence, antioxidant systems, and lipid peroxidation at the end of growing season. High O₃ concentration reduced F_v/F_m, indicating that the efficiency in the energy conversion of photosystem 2 (PS2) was altered. The rate of non-cyclic electron transport rate and the capacity to reduce the quinone pool were also affected. The development of non-photochemical quenching was not high enough to decrease the photon excess in the...

Photoprotective Function of Photorespiration in Several Grapevine Cultivars Under Drought Stress

X.Q. Guan, S.J. Zhao, D.Q. Li, H.R. Shu

Photosynthetica 2004, 42(1):31-36 | DOI: 10.1023/B:PHOT.0000040566.55149.52

Four grapevine cultivars, i.e. Cabernet Sauvignon (a member of the Western Europe cultivar group), Rizamat (a member of the East cultivar group), Red Double Taste (a hybridized cultivar from Vitis vinifera L. and V. labrusca L.), and 1103Paulsen (a hybridized rootstock), were treated by three severity orders of drought stress for 25 d. Then net photosynthetic rate (P_N), maximal photochemical efficiency (F_v/F_m), actual photochemical efficiency (Φ_PS2) of photosystem 2, total electron transport rate (J_T), and electron transport flows used in carboxylation (J_C)...

Peanut Photosynthesis Under Drought and Re-Watering

J.A. Lauriano, J.C. Ramalho, F.C. Lidon, M. do Céu Matos

Photosynthetica 2004, 42(1):37-41 | DOI: 10.1023/B:PHOT.0000040567.42444.c2

The photosynthetic response of three Arachis hypogaea L. cultivars (57-422, 73-30, and GC 8-35) grown for two months was measured under water available conditions, severe water stress, and 24, 72, and 93 h following re-watering. At the end of the drying cycle, all the cultivars reached dehydration, relative water content (RWC) ranging between 40 and 50 %. During dehydration, leaf stomatal conductance (g_s), transpiration rate (E), and net photosynthetic rate (P_N) decreased more in cvs. 57-422 and GC 8-35 than in 73-30. Instantaneous water use efficiency (WUE_i) and photosynthetic capacity (P_max)...

Photosynthetic Enzymes of the C₄ Grass Setaria sphacelata Under Water Stress: A Comparison Between Rapidly and Slowly Imposed Water Deficit

J. Marques Da Silva, M.C. Arrabaça

Photosynthetica 2004, 42(1):43-47 | DOI: 10.1023/B:PHOT.0000040568.58103.ca

Two stress imposing systems were used: a rapid stress developed by allowing excised leaves to loose water by transpiration, and a slow stress developed by withholding watering of potted plants. Carboxylating enzymes reacted differently on both types of stress. Rapid stress increased ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activation, but both activities (initial and total) showed little variation with stress. Under slow stress the activation did not change, although both activities decreased much under stress. Phosphoenolpyruvate carboxylase (PEPC) showed a deep decrease of activity under rapid stress, nevertheless, a certain...

Negative Effects of P-Buffering and pH on Photosynthetic Activity of Planktonic Desmid Species

E. Spijkerman, E. Garcia-Mendoza, H.C.P. Matthijs, E. Van Hunnik, P.F.M. Coesel

Photosynthetica 2004, 42(1):49-57 | DOI: 10.1023/B:PHOT.0000040569.17719.2a

The photosynthetic activities of three planktonic desmid species (Staurastrum brachiatum, Staurodesmus cuspidatus var. curvatus, and Staurastrum chaetoceras) were compared after adaptation to medium enriched with either a 20 mM Na⁺-phosphate (P) or HEPES buffer. Incubations up to 2 d were carried out at pH 6 or 8 under normal air or air enriched with 5 % CO₂. Gross maximum photosynthetic rate (P_max) and growth rate were decreased in both S. brachiatum and Std. cuspidatus at higher pH when using the HEPES buffer and this effect was independent of CO₂ concentration,...

Decay Kinetics of Tyrosine Radical (Y_Z^*) in Chloride Anion-Depleted Photosystem 2 Studied by Time-Resolved EPR

A. Jajoo, S. Bharti, A. Kawamori

Photosynthetica 2004, 42(1):59-64 | DOI: 10.1023/B:PHOT.0000040570.39971.63

The decay of tyrosine cation radical was found to be biphasic at 253 K. The fast phase corresponds to the Y_Z^* component while the slow phase corresponds to the tyrosine D radical (Y_D^*) component. At 253 K, the t_1/2 value was ∼28.6 s for the fast phase and ∼190.7 s for the slow phase. The fast phase is attributed to the recombination of charges between Y_Z^* and Q_A^-. The activation energy for the reaction of Y_Z with Q_A^- between 253 and 293 K was 48 kJ mol^-1 in Cl^--depleted photosystem 2 (PS2)...

Photosynthesis, Transpiration, and Water Use Efficiency of Caragana microphylla, C. intermedia, and C. korshinskii

C.C. Ma, Y.B. Gao, H.Y. Guo, J.L. Wang

Photosynthetica 2004, 42(1):65-70 | DOI: 10.1023/B:PHOT.0000040571.63254.c2

In the order C. microphylla - C. intermedia - C. korshinskii, compensation irradiance, saturation irradiance, and optimum temperature for photosynthesis increased, net photosynthetic rate (P_N) at low irradiance and low temperature decreased, optimum air humidity decreased, and P_N at low air humidity increased. Daily cumulative value of P_N increased while daily cumulative value of transpiration (E) decreased, and hence water use efficiency (WUE =P_N/E) increased. Diurnal course of P_N of C. microphylla was a double-peak curve, but the...

C₄ Species and their Response to Large-Scale Longitudinal Climate Variables Along the Northeast China Transect (NECT)

R.Z. Wang

Photosynthetica 2004, 42(1):71-79 | DOI: 10.1023/B:PHOT.0000040572.95053.76

Natural occurrence of C₄ species, life forms, and their longitudinal distribution patterns along the Northeast China Transect (NECT) were studied. Six vegetation regions experiencing similar irradiation regimes, but differing in longitude, precipitation, and altitude were selected along the NECT from 108 to 131 °E, around altitude of 43.5 °N. Seventy C₄ species were identified in 41 genera and 13 families. 84 % of the total C₄ species were found in four families: Gramineae (38 species), Chenopodiaceae (11 species), Cyperaceae (5 species), and Amaranthaceae (5 species). C₄ grasses...

Leaf Gas Exchange and Water Relations of Grapevines Grown in Three Different Conditions

J.M. Moutinho-Pereira, C.M. Correia, B.M. Gonçalves, E.A. Bacelar, J.M. Torres-Pereira

Photosynthetica 2004, 42(1):81-86 | DOI: 10.1023/B:PHOT.0000040573.09614.1d

Diurnal and seasonal changes in the leaf water potential (Ψ), stomatal conductance (g_s), net CO₂ assimilation rate (P_N), transpiration rate (E), internal CO₂ concentration (C_i), and intrinsic water use efficiency (P_N/g_s) were studied in grapevines (Vitis vinifera L. cv. Touriga Nacional) growing in low, moderate, and severe summer stress at Vila Real (VR), Pinhão (PI), and Almendra (AL) experimental sites, respectively. In VR and PI site the limitation to photosynthesis was caused more by stomatal limitations, while...

Photosynthesis and Growth Responses of Parthenocissus quinquefolia (L.) Planch to Soil Water Availability

Z.J. Zhang, L. Shi, J.Z. Zhang, C.Y. Zhang

Photosynthetica 2004, 42(1):87-92 | DOI: 10.1023/B:PHOT.0000040574.25273.59

Photosynthesis and growth characteristics of Parthenocissus quinquefolia were measured under differing soil water availability within a pot. Decreased soil moisture significantly reduced the leaf relative water content (RWC) and the above- and below-ground biomass. However, more biomass was allocated to the root than to the leaf. Net photosynthetic rate (P_N), stomatal conductance (g_s), and transpiration rate (E) were also significantly decreased but water use efficiency (WUE) was increased. Midday depressions in P_N and g_s were not evident for the well-irrigated plants....

Significance of the Leaf Area Ratio in Hevea brasiliensis Under High Irradiance and Low Temperature Stress

D. Ray, S.K. Dey, G. Das

Photosynthetica 2004, 42(1):93-97 | DOI: 10.1023/B:PHOT.0000040575.92512.ab

Adjustment in leaf area : mass ratio called leaf area ratio (LAR) is one of the strategies to optimize photon harvesting. LAR was recorded for 10 genotypes of Hevea brasiliensis under high irradiance and low temperature and the genotypes were categorized into two groups, i.e. high LAR and low LAR types. Simultaneously, the growth during summer as well as winter periods, photosynthetic characteristics, and in-vitro oxidative damage were studied. Low LAR (19.86±0.52 m² kg^-1) types, recorded an average of 18.0 % chlorophyll (Chl) degradation under high irradiance and 7.1 % Chl degradation under low temperature....

Contribution of Pre-Anthesis Assimilates and Current Photosynthesis to Grain Yield, and their Relationships to Drought Resistance in Wheat Cultivars Grown Under Different Soil Moisture

T. Inoue, S. Inanaga, Y. Sugimoto, K. El Siddig

Photosynthetica 2004, 42(1):99-104 | DOI: 10.1023/B:PHOT.0000040576.52128.ed

We investigated the relative importance of pre-anthesis assimilates stored in plant parts, mainly in the stem, and post-anthesis photosynthesis to drought resistance in wheat (Triticum aestivum L.) cultivars Hongwangmai (drought resistant) and Haruhikari (drought sensitive) subjected to two soil moisture regimes: irrigated and non-irrigated. In the irrigated treatment, soil moisture was maintained near field capacity throughout the growing season, while in the non-irrigated treatment water was withheld from 81 d after sowing until maturity. Drought stress reduced grain yield of Hongwangmai and Haruhikari by 41 and 60 %, respectively. Remobilization...

Exogenous Hexoses Cause Quantitative Changes of Pigment and Glycerolipid Composition in Filamentous Cyanobacteria

N.F. Mykhaylenko, O.O. Syvash, N.D. Tupik, O.K. Zolotareva

Photosynthetica 2004, 42(1):105-110 | DOI: 10.1023/B:PHOT.0000040577.30424.d1

Cyanobacteria Spirulina platensis and Nostoc linckia were grown in the presence of 5 mM and 50 mM glucose or 5 mM mannose, non-metabolisable glucose analogue that effectively triggers the repression of photosynthesis. Glucose evoked active cyanobacterial growth but chlorophyll (Chl) content decreased to some extent and porphyrins were excreted. The content of monogalactosyldiacylglycerol decreased in glucose-grown cyanobacteria and that of phosphatidylglycerol increased substantially. Mannose inhibited cyanobacteria growth as well as Chl synthesis, however, phosphatidylglycerol contents were higher than in respective control samples....

Interactive Effects of Salinity and Ozone Pollution on Photosynthesis, Stomatal Conductance, Growth, and Assimilate Partitioning of Wheat (Triticum aestivum L.)

I.A. Hassan

Photosynthetica 2004, 42(1):111-116 | DOI: 10.1023/B:PHOT.0000040578.93542.61

Plants of an Egyptian cultivar of wheat (Triticum aestivum L. cv. Giza 63) were exposed in open-top chambers (OTCs) for 8 h d^-1 for up to 75 d to a factorial combination of two levels of salinity (0 and 50 mM NaCl) and two levels of O₃ (filtered air and 50 mm³ m^-3). Exposure to 50 mm³ m^-3 O₃ significantly decreased stomatal conductance (g_s), net photosynthetic rate (P_N), and chlorophyll (Chl) content by 20, 25, and 21 %, respectively. This reduction resulted in a change in assimilate allocation in favour of shoot growth leading to...

Dissipation of Excess Energy in Mehler-Peroxidase Reaction in Rumex Leaves During Salt Shock

H. X. Chen, H. Y. Gao, S. Z. An, W. J. Li

Photosynthetica 2004, 42(1):117-122 | DOI: 10.1023/B:PHOT.0000040579.37842.ca

By measurement of gas exchange and chlorophyll fluorescence, the effects of salt shock on photosynthesis and the mechanisms to protect photosynthetic machinery against photodamage during salt shock were investigated in leaves of Rumex seedlings. Salt shock induced significant decrease in photosynthesis both in 21 and 2 % O₂. In 21 % O₂, quantum yield of photosystem 2 (PS2) electron transport (Φ_PS2) decreased slightly and q_P remained constant, suggesting that the excitation pressure on PS2 did not increase during salt shock. In 2 % O₂, however, both Φ_PS2 and q_P...

Function of Node Unit in Photosynthate Distribution to Root in Higher Plants

M. Osaki, T. Shinano, M. Yamada, S. Yamada

Photosynthetica 2004, 42(1):123-131 | DOI: 10.1023/B:PHOT.0000040580.22939.55

Leaf-root interaction is a critical factor for plant growth during maturation and activity of roots is maintained by a sufficient supply of photosynthates. To explain photosynthate distribution among organs in field crops, the node unit hypothesis is proposed. One node unit consists of a leaf and an upper adventitous root, as well as the axillary organs and the lower adventitious root, which is adjacent to one node. Using ¹⁴C as tracer, the carbon distribution system has been clarified using spring wheat, soybean, tomato, and potato. The interrelationship among organs from the strongest to the weakest is in the following order: (1)...

Leaf Gas Exchange and Water Relations in Polylepis tarapacana at Extreme Altitudes in the Bolivian Andes

C. García-Núñez, F. Rada, C. Boero, J. González, M. Gallardo, A. Azócar, M. Liberman-Cruz, M. Hilal, F. Prado

Photosynthetica 2004, 42(1):133-138 | DOI: 10.1023/B:PHOT.0000040581.94641.ed

Stress-induced restrictions to carbon balance, growth, and reproduction are the causes of tree-line formation at a global scale. We studied gas exchange and water relations of Polylepis tarapacana in the field, considering the possible effects of water stress limitations imposed on net photosynthetic rate (P_N). Daily courses of microclimatic variables, gas exchange, and leaf water potential were measured in both dry-cold and wet-warm seasons at an altitude of 4 300 m. Marked differences in environmental conditions between seasons resulted in differences for the dry-cold and wet-warm seasons in mean leaf water potentials (-1.67...

Application of a Chlorophyll Fluorescence Sensor to Detect Chelate-Induced Metal Stress in Zea mays

J.J. Colls, D.P. Hall

Photosynthetica 2004, 42(1):139-145 | DOI: 10.1023/B:PHOT.0000040582.68474.e3

Metal stress was induced in maize (Zea mays L.) by the addition to the soil of a range of concentrations of either ethylene-diamine-tetra-acetate (EDTA) or citric acid (CA) as chelating agents. Measurements were taken using a recently-developed sensor capable of plant fluorescence detection at wavelengths of 762 and 688 nm. Atmospheric oxygen absorbs radiation at these wavelengths. As such, measured fluorescence can be attributed to the plants under observation. Red/far-red (690/760 nm, R/FR) chlorophyll (Chl) fluorescence ratios were measured before addition of the chelating agents and during the month following. Significant differences were...

Dual Role of Superoxide Radicals in the Chilling-Induced photoinhibition in Maize Seedlings

D. Ke, G. Sun, Y. Jiang

Photosynthetica 2004, 42(1):147-152 | DOI: 10.1023/B:PHOT.0000040583.78295.f7

Maize (Zea mays) seedlings were exposed for 6 h to strong irradiance (1 000 μmol m^-1 s^-1 of PPFD) at 5, 12, 17, or 25 °C, followed by an exposure to the darkness for 6 h at 22 °C. Leaf chlorophyll fluorescence, net photosynthetic rate (P_N), and the amount of superoxide radicals (O₂^-⋅) in relation to chilling-induced photoinhibition were investigated. During the photophase, a good correlation (r=-0.879) was observed between Φ_PS2 (relative quantum efficiency of PS2 electron transport) and the amount of O₂^-⋅. Treatment with exogenous...

High Irradiance Effects on the Xanthophyll Cycle Pigments and the Activity of Violaxanthin De-Epoxidase in Soybean Callus

D.M. Pandey, K.H. Kim, K.H. Kang, U.D. Yeo

Photosynthetica 2004, 42(1):153-156 | DOI: 10.1023/B:PHOT.0000040584.93955.a1

High irradiance (HI) effects on xanthophyll cycle pigments (XCP) and activity of violaxanthin de-epoxidase (VDE) in terms of de-epoxidation index (DEI) were studied in soybean calli. The calli from the hypocotyl segments of 5-d seedlings were induced on a solid (1.1 % agar) MS medium (pH 5.8) supplemented with 4.52 μM 2,4-dichloro-phenoxyacetic acid, 2.32 μM kinetin, and 3 % sucrose. After a 30 d cultivation, the green calli were irradiated for 24 h with "white light" (HI, 1 300 μmol m^-2 s^-1) and VDE was isolated from the photosystem 2 (PS2) particles. In the control (0 h irradiation) callus, the reaction of PS2 particles...

Growth and Leaf Gas Exchange Characteristics in Dalbergia sissoo Roxb. and D. latifolia Roxb. Under Water Deficit

M. Ashraf, M.Y. Ashraf, Abdul Khaliq, Eui Shik Rha

Photosynthetica 2004, 42(1):157-160 | DOI: 10.1023/B:PHOT.0000040585.31593.38

Forty two-month-old plants of Dalbergia sissoo and D. latifolia were subjected for 56 d to water deficit induced by withholding water. Drought stress caused a significant reduction in plant height, stem diameter, net photosynthetic rate (P_N), transpiration rate (E), and stomatal conductance (g_s) in both species, but the reduction was greater in D. sissoo than in D. latifolia. Water use efficiency (P_N/E) was adversely affected due to water stress only in D. latifolia, and intrinsic water use efficiency (P_N/g_s) was...