The negative effects of clethodim in photosynthesis and gas-exchange status of maize plants are ameliorated by salicylic acid pretreatment

D. E. M. Radwan, D. M. Soltan

Photosynthetica 2012, 50(2):171-179 | DOI: 10.1007/s11099-012-0016-8

In this work, the injuries caused by clethodim herbicide application as well as the use of exogenous salicylic acid (SA) as a protective agent against clethodim in Zea mays leaves were examined. Although the target for clethodim is the inhibition of acetyl coenzyme A carboxylase (ACCase) which is the key enzyme for fatty acid biosynthesis, it can indirectly affect the photosynthetic machinery, gaseous exchange and some biochemical parameters. Clethodim application caused chlorosis and yellowing of leaf-tip parts. Higher doses caused browning or reddening of leaves and sometimes dead parts of the leaf margins were observed. The rate of photosynthesis...

Improving melon and cucumber photosynthetic activity, mineral composition, and growth performance under salinity stress by grafting onto Cucurbita hybrid rootstocks

Y. Rouphael, M. Cardarelli, E. Rea, G. Colla

Photosynthetica 2012, 50(2):180-188 | DOI: 10.1007/s11099-012-0002-1

The aim of the current work was to determine whether grafting could improve salinity tolerance of melon and cucumber, and whether possible induction of tolerance to salt stress was associated with the protection of the photosynthetic apparatus. Two greenhouse experiments were carried out to determine gas exchange, mineral composition, growth and yield of melon (Cucumis melo L. cv. Cyrano) and cucumber (Cucumis sativus L. cv. Akito) plants, either ungrafted or grafted onto the Cucurbita hybrid rootstocks (Cucurbita maxima Duch. × Cucurbita moschata Duch.), 'P360', and 'PS1313', respectively. Plants were grown hydroponically...

Photosynthesis and activity of photosystem II in response to drought stress in Amur Grape (Vitis amurensis Rupr.)

Z. X. Wang, L. Chen, J. Ai, H. Y. Qin, Y. X. Liu, P. L. Xu, Z. Q. Jiao, Y. Zhao, Q. T. Zhang

Photosynthetica 2012, 50(2):189-196 | DOI: 10.1007/s11099-012-0023-9

The Amur Grape (Vitis amurensis Rupr.) cultivars 'shuangFeng' and 'ZuoShanyi' were grown in shelter greenhouse under natural sunlight and subjected to drought. Sap flow rate, net photosynthetic rate (P _N), and chlorophyll (Chl) fluorescence were measured on Amur Grape leaves subjected to different drought treatments. Significant decreases in P _N were associated with increasing intercellular CO₂ concentration (C _i), suggesting that the reduction in P _N was caused by nonstomatal limitation. Analysis of OJIP transients according to the JIP-test protocol revealed...

Chloroplast functionality assessment by flow cytometry: Case study with pea plants under Paraquat stress

E. Rodriguez, R. Azevedo, A. Costa, J. Serôdio, C. Santos

Photosynthetica 2012, 50(2):197-205 | DOI: 10.1007/s11099-012-0022-x

Photosynthesis is one of the most important processes in plant biology and in the development of new methodologies that allow a better understanding and characterization of the photosynthetic status of organisms, which is invaluable. Flow cytometry (FCM) is an excellent tool for measuring fluorescence and physical proprieties of particles but it has seldom been used in photosynthetic studies and thus the full extent of its potentialities, in this field of research, remains unknown. To determine the suitability of FCM in photosynthesis studies, pea plants were exposed to Paraquat and their status was analyzed during 24 h. FCM was used to evaluate the...

Using combined measurements of gas exchange and chlorophyll fluorescence to investigate the photosynthetic light responses of plant species adapted to different light regimes

S. L. Wong, C. W. Chen, H. W. Huang, J. H. Weng

Photosynthetica 2012, 50(2):206-214 | DOI: 10.1007/s11099-012-0027-5

One broad-leaved pioneer tree, Alnus formosana, two broad-leaved understory shrubs, Ardisia crenata and Ardisia cornudentata, and four ferns with different light adaptation capabilities (ranked from high to low, Pyrrosia lingus, Asplenium antiquum, Diplazium donianum, Archangiopteris somai) were used to elucidate the light responses of photosynthetic rate and electron transport rate (ETR). Pot-grown materials received up to 3 levels of light intensity, i.e., 100%, 50% and 10% sunlight. Both gas exchange and chlorophyll (Chl) fluorescence were measured simultaneously by an equipment under constant temperature and 7...

Maize photosynthesis and microclimate within the canopies at grain-filling stage in response to narrow-wide row planting patterns

T. D. Liu, F. B. Song

Photosynthetica 2012, 50(2):215-222 | DOI: 10.1007/s11099-012-0011-0

In China, narrow-wide row planting pattern has been advocated for maize (Zea mays L.) production. However, no previous study has clearly elucidated the complexity of factors affecting maize canopy such as the microclimatic factors, and the effect of photosynthesis in narrow-wide row planting pattern. The current study was undertaken to identify the planting patterns that influence microclimatic conditions and photosynthesis of two maize cultivars (Beiyu288 and Xianyu335) grown in three planting patterns: narrow-wide rows of (1) 30 cm + 170 cm (P1, 6.4 plants m^-2), and (2) 40 cm + 90 cm (P2, 6.4 plants m^-2),...

Quantifying the measurement errors in a portable open gas-exchange system and their effects on the parameterization of Farquhar et al. model for C₃ leaves

Q. Wang, D. H. Fleisher, D. Timlin, V. R. Reddy, J. A. Chun

Photosynthetica 2012, 50(2):223-238 | DOI: 10.1007/s11099-012-0012-z

A portable open gas-exchange system (Li-6400, Li-Cor, Inc., Lincoln, NE, USA) has been widely used for the measurement of net gas exchanges and calibration/parameterization of leaf models. Measurement errors due to diffusive leakage rates of water vapor (L_W) and CO₂ (L_C) between inside and outside of the leaf chamber, and the inward dark transpiration rate (D_W) and dark respiration rate (D_C) released from the leaf under the gasket, can be significant. Rigorous model-based approaches were developed for estimating leakage coefficients of water vapor (K_W) and CO₂ (K_C)...

Photosynthetic behavior of Spanish Arbequina and Italian Maurino olive (Olea europaea L.) cultivars under super-intensive grove conditions

P. Proietti, L. Nasini, L. Ilarioni

Photosynthetica 2012, 50(2):239-246 | DOI: 10.1007/s11099-012-0025-7

The study was carried out in a four-year-old super-high density olive grove in Central Italy to compare leaf gas exchanges of Spanish Arbequina and Italian Maurino olive cultivars. Overall, from mid July to mid November, Maurino had a slightly higher maximum light-saturated net photosynthetic rate (P _Nmax) than Arbequina. The lowest and the highest P _Nmax values were recorded at the end of July and in mid November, respectively. Current-season leaves showed similar or slightly higher P _Nmax values than one-year-old leaves. During the day Maurino always had slightly higher values or values similar...

Specificity factor of Rubisco: estimation in intact leaves by carboxylation at different CO₂/O₂ ratios

J. Viil, H. Ivanova, T. Pärnik

Photosynthetica 2012, 50(2):247-253 | DOI: 10.1007/s11099-012-0026-6

The specificity factor of Rubisco (S _f) was estimated in intact leaves from the carboxylation of ribulose-1,5-bisphosphate (RuBP) at various CO₂/O₂ ratios. As oxygenation is calculated by the difference of the ¹⁴CO₂ uptake by RuBP in the absence and presence of oxygen, it is important to choose the optimum CO₂/O₂ ratios. At high CO₂ concentration (1,000 cm³ m^-3 and higher) oxygenation consumes less than 50% RuBP but the difference of concentrations of CO₂ at cell walls (C _w) and at the carboxylation centers...

Foliar anthocyanins in Pelargonium × hortorum are unable to alleviate light stress under photoinhibitory conditions

G. Liakopoulos, I. Spanorigas

Photosynthetica 2012, 50(2):254-262 | DOI: 10.1007/s11099-012-0031-9

Photosynthetic organs are often characterized by anthocyanins being accumulated either in the epidermal or in the mesophyll cells making these tissues to turn reddish-brown in colour. It has been hypothesized that these pigments protect underlying chloroplasts from light-stress because they absorb photons of the photosynthetically active waveband. However, the photoprotective role of anthocyanins has not been undoubtedly shown on a broad range of species. In this study, green and anthocyanic areas of leaves of Pelargonium × hortorum, the latter possessing variable levels of anthocyanins, were compared using pigment analysis and pulse amplitude...

Effect of plant growth promoting Bacillus subtilis and Pseudomonas fluorescens on growth and pigment composition of radish plants (Raphanus sativus) under NaCl stress

H. I. Mohamed, E. Z. Gomaa

Photosynthetica 2012, 50(2):263-272 | DOI: 10.1007/s11099-012-0032-8

Soil salinity is one of the most severe factors limiting growth and physiological response in Raphanus sativus. In this study, the possible role of plant growth promoting bacteria (PGPB) in alleviating soil salinity stress during plant growth under greenhouse conditions was investigated. Increasing salinity in the soil decreased plant growth, photosynthetic pigments content, phytohormones contents (indole-3-acetic acid, IAA and gibberellic acid, GA₃) and mineral uptake compared to soil without salinity. Seeds inoculated with Bacillus subtilis and Pseudomonas fluorescens caused significantly increase in fresh and dry...

Photosynthetic nitrogen and water use efficiency of acacia and eucalypt seedlings as afforestation species

E. Novriyanti, M. Watanabe, K. Makoto, T. Takeda, Y. Hashidoko, T. Koike

Photosynthetica 2012, 50(2):273-281 | DOI: 10.1007/s11099-012-0033-7

The ecophysiological traits of acacia and eucalypt are important in assessing their suitability for afforestation. We measured the gas-exchange rate, the leaf dry mass per area (LMA) and the leaf nitrogen content of two acacia and four eucalypt species. Relative to the eucalypts, the acacias had lower leaf net photosynthetic rate (P _N), lower photosynthetic nitrogen-use efficiency (PNUE), higher water-use efficiency (WUE), higher LMA and higher leaf nitrogen per unit area (N _area). No clear differences were observed within or between genera in the maximum rate of carboxylation (V _cmax) or the maximum...

Ecophysiological characteristics of two carrot (Daucus carota L.) cultivars in response to agroecological factors and nitrogen application

A. Thiagarajan, R. Lada, A. Adams

Photosynthetica 2012, 50(2):282-290 | DOI: 10.1007/s11099-012-0034-6

Plant density, planting time, harvest timing, and nitrogen influence on short-term gas-exchange properties of carrot cultivars, Topcut and Sugarsnax (Daucus carota L.) were investigated under field conditions. Net photosynthetic rate (P _N), stomatal conductance (g _s), and transpiration rate (E) differed significantly with the cultivars studied. Both planting and harvest timing changed the midday P _N rates. P _N increased as harvest timing advanced regardless of planting time. Late planting combined with late harvesting registered the maximum P _N rates...

A universal method for the isolation of photochemically active broken chloroplasts from conifer needles and its possible application in photosynthetic studies

D. Holá, M. Kočová, O. Rothová, E. Hlízová, L. Fridrichová, Z. Lhotáková, J. Albrechtová

Photosynthetica 2012, 50(2):291-304 | DOI: 10.1007/s11099-012-0028-4

We have developed a simple and an effective method for the isolation of photochemically active broken chloroplasts from conifer needles that can be applied for a wide variety of conifer species with needle-like leaves. The utilisation of this method in photosynthetic studies offers a possibility to examine the efficiency of almost any component of thylakoid electron-transport chain and to disclose information about individual parts of primary photosynthetic processes that would be otherwise difficult to obtain. Various aspects influencing the outcome of this procedure, including the amount of needles necessary for sufficient yields, the possible length...

Improving growth, flower yield, and water relations of snapdragon (Antirhinum majus L.) plants grown under well-watered and water-stress conditions using arbuscular mycorrhizal fungi

A. A. Asrar, G. M. Abdel-Fattah, K. M. Elhindi

Photosynthetica 2012, 50(2):305-316 | DOI: 10.1007/s11099-012-0024-8

The influence of arbuscular mycorrhizal (AM) fungus Glomus deserticola (Trappe and John) on plant growth, nutrition, flower yield, water relations, chlorophyll (Chl) contents and water-use efficiency (WUE) of snapdragon (Antirhinum majus cv. butterfly) plants were studied in potted culture under well-watered (WW) and water-stress (WS) conditions. The imposed water stress condition significantly reduced all growth parameters, nutrient contents, flower yield, water relations, and Chl pigment content and increased the electrolyte leakage of the plants comparing to those of nonstressed plants. Regardless of the WS level, the mycorrhizal snapdragon...

Analyzing the significance of defoliation in growth, photosynthetic compensation and source-sink relations

N. Iqbal, A. Masood, N. A. Khan

Photosynthetica 2012, 50(2):161-170 | DOI: 10.1007/s11099-012-0029-3

Leaf canopy plays a determining role influencing source-sink relations as any change in source activity (photosynthesis) affects sink metabolism. Defoliation (removal of leaves) influences growth and photosynthetic capacity of plants, remobilizes carbon and nitrogen reserves and accelerates sink metabolism, leading to improved source-sink relations.
The response of plants to defoliation could be used to manipulate source-sink relations by removing lower and senescing leaves to obtain greatest photosynthetic capacity and efficient carbon and nitrogen metabolism under optimal and stressful environments. The present work enhances our current understanding...

Photosynthesis Research Protocols. 2nd Ed.

J. Nauš

Photosynthetica 2012, 50(2):290

Photosynthesis-nitrogen relationship in a Hinoki cypress (Chamaecyparis obtusa) canopy: a comparison with Japanese cedar (Cryptomeria japonica)

H. Kobayashi, S. Inoue, K. Gyokusen

Photosynthetica 2012, 50(2):317-320 | DOI: 10.1007/s11099-012-0030-x

The relationship between light-saturated photosynthetic capacity (P _max) and leaf nitrogen (N) content was investigated for one year in a 15-year-old Chamaecyparis obtusa canopy and was compared with a Cryptomeria japonica canopy previously described. The linear regression between P _max and leaf N content tended to converge toward a single line segment from July to January and in May for C. obtusa. The slope of the linear regression between P _max and leaf N content of C. obtusa was gentler than that of C. japonica. The smaller regression coefficient of C. obtusa...