Seasonal and interannual variations of ecosystem photosynthetic features in an alpine dwarf shrubland on the Qinghai-Tibetan Plateau, China

H. Q. Li, F. W. Zhang, Y. N. LI, G. M. Cao, L. Zhao, X. Q. Zhao

Photosynthetica 2014, 52(3):321-331 | DOI: 10.1007/s11099-014-0035-8

Ecosystem photosynthetic characteristics are of utmost importance for the estimation of regional carbon budget, but such characteristics are not well understood in alpine regions. We collected CO₂ flux data measured by eddy covariance technique over an alpine dwarf shrubland on the Qinghai-Tibetan Plateau during years 2003-2010; and we quantified the temporal patterns of ecosystem apparent quantum yield (a), saturated photosynthetic rate (P _max), and ecosystem dark respiration (R _De). Results showed that the strong seasonality of a and R _De was driven mainly by air temperature...

Growth and photosynthetic responses of soybean seedlings to maize shading in relay intercropping system in Southwest China

B. Y. Su, Y. X. Song, C. Song, L. Cui, T. W. Yong, W. Y. Yang

Photosynthetica 2014, 52(3):332-340 | DOI: 10.1007/s11099-014-0036-7

Intercropping, a traditional and worldwide cropping practice, has been considered as a paradigm of sustainable agriculture based on complementary mechanisms among different crop species. Soybean (Glycine max) is widely relay intercropped about 60 days before maize (Zea mays) harvest in Southwest China. However, shade caused by tall maize plants may be a limiting factor for soybean growth at a seedling stage. In field research, we studied the ecophysiological responses of two widely cultivated soybean varieties [Gongqiudou494-1 (GQD) and Gongxuan 1 (GX)] to maize shading in a relay intercropping system (RI) compared with monocropped soybean...

Severe water deficit-induced ethylene production decreases photosynthesis and photochemical efficiency in flag leaves of wheat

W. Yang, Y. Yin, W. Jiang, D. Peng, D. Yang, Y. Cui, Z. Wang

Photosynthetica 2014, 52(3):341-350 | DOI: 10.1007/s11099-014-0037-6

Wheat (Triticum aestivum L.) cv. Jimai22 was used to evaluate the effect of ethylene evolution rate (EER) and 1-aminocyclopropane-1-carboxylic acid (ACC) and their relations with photosynthesis and photochemical efficiency in plants well-watered (WW) and under a severe water deficit (SWD). SWD caused a noticeable reduction in the grain mass. The marked increases in both EER and the ACC concentration were observed under SWD; it was reversed effectively by exogenous spermidine (Spd) or amino-ethoxyvinylglycine (AVG). Thermal images indicated that SWD increased obviously the temperature of flag leaves, mainly due to the decrease in transpiration...

Photosynthetic acclimation in shade-developed leaves of Euterpe edulis Mart (Arecaceae) after long-term exposure to high light

A. O. Lavinsky, F. P. Gomes, M. S. Mielke, S. França

Photosynthetica 2014, 52(3):351-357 | DOI: 10.1007/s11099-014-0038-5

To analyze acclimation of Euterpe edulis seedlings to changes in light availability, we transferred three-year-old seedlings cultivated for six months under natural shade understory [≈ 1.3 mol(photon) m^-2 d^-1] to a forest gap [≈ 25.0 mol(photon) m^-2 d^-1]. After the transfer, changes in chlorophyll fluorescence and leaf gas-exchange parameters, as well as in the light-response curves of photosynthesis and photosynthetic induction parameters, were analyzed during the following 110 days. Simultaneously measured photosynthetic characteristics in the shaded seedlings grown in understory served...

Effect of the replacement of a native savanna by an African Brachiaria decumbens pasture on the CO₂ exchange in the Orinoco lowlands, Venezuela

J. San José, R. Montes, N. Nikonova, J. Grace, C. Buendía

Photosynthetica 2014, 52(3):358-370 | DOI: 10.1007/s11099-014-0039-4

In the Orinoco lowlands, savannas have been often replaced by pastures composed of the C₄ grass, Brachiaria decumbens Stapf. We addressed following questions: (1) How does the replacement of the native vegetation affect CO₂ exchange on seasonal and annual scales? (2) How do biophysical constraints change when the landscape is transformed? To assess how these changes affect carbon exchange, we determined simultaneously the CO₂ fluxes by eddy covariance, and the soil CO₂ efflux by a chamber-based system in B. decumbens and herbaceous savanna stands. Measurements covered a one-year...

Effects of guttation prevention on photosynthesis and transpiration in leaves of Alchemilla mollis

Y. C. Chen, T. C. Lin, C. E. Martin

Photosynthetica 2014, 52(3):371-376 | DOI: 10.1007/s11099-014-0040-y

The ecophysiological function(s) and consequences of guttation, a phenomenon by which water is exuded by and accumulated as droplets along the leaf margins under high humidity in many plants that grow in wet soil, has been poorly studied and remains largely unknown. Thus, leaf gas exchange and chlorophyll fluorescence were examined, using two experimental approaches, in Alchemilla mollis plants under conditions that promoted guttation and those that prevented this phenomenon. Although results were variable, depending on the experimental approach, prevention of guttation effected reductions in photosynthesis and transpiration, as well as photochemical...

Photosynthetic responses of wheat (Triticum aestivum L.) to combined effects of drought and exogenous methyl jasmonate

C. Ma, Z. Q. Wang, L. T. Zhang, M. M. Sun, T. B. Lin

Photosynthetica 2014, 52(3):377-385 | DOI: 10.1007/s11099-014-0041-x

Drought stress limits wheat growth and productivity. The response of wheat (Triticum aestivum L.) to different water supply conditions (well-watered and drought-stressed) and exogenous methyl jasmonate (MeJA; 0 and 0.25 μM) was studied. The application of MeJA enhanced wheat adaptability to drought stress by physiological and metabolic adjustments. Drought stress reduced net photosynthetic rate (P _N), stomatal conductance (g _s), transpiration rate (E), and water-use efficiency (WUE) in wheat. The application of exogenous MeJA decreased also g _s and E, but stimulated WUE....

Leaf traits variation in Sesleria nitida growing at different altitudes in the Central Apennines

L. Gratani, M. F. Crescente, V. D'Amato, C. Ricotta, A. R. Frattaroli, G. Puglielli

Photosynthetica 2014, 52(3):386-396 | DOI: 10.1007/s11099-014-0042-9

Global climate change may act as a potent agent of natural selection within species with Mediterranean mountain ecosystems being particularly vulnerable. The aim of this research was to analyze whether the phenotypic plasticity of Sesleria nitida Ten. could be indicative of its future adaptive capability to global warming. Morphological, anatomical, and physiological leaf traits of two populations of S. nitida growing at different altitudes on Mount Terminillo (Italy) were analyzed. The results showed that leaf mass per unit leaf area, leaf tissue density, and total leaf thickness were 19, 3, and 31% higher in leaves from the population...

Rice varietal differences in responses of stomatal gas exchange to supplemental nitrogen application

S. Shimoda, A. Maruyama

Photosynthetica 2014, 52(3):397-403 | DOI: 10.1007/s11099-014-0043-8

In the field, supplemental application of N fertilizer to rice (Oryza sativa) shortly before the beginning of heading stage increases leaf N content and enhances photosynthesis during the grain-filling period. In search of varietal differences in leaf gas exchange in response to supplemental N application, we examined 13 rice varieties grown in the field during two successive years. The varieties included japonica and indica varieties, both of which are widely grown in Japan. The response to supplemental N application could not be separated clearly between variety groups; some of the japonica varieties, but none of the indica...

Water stress and abscisic acid treatments induce the CAM pathway in the epiphytic fern Vittaria lineata (L.) Smith

B. D. Minardi, A. P. L. Voytena, M. Santos, Á. M. Randi

Photosynthetica 2014, 52(3):404-412 | DOI: 10.1007/s11099-014-0047-4

Among various epiphytic ferns found in the Brazilian Atlantic Forest, we studied Vittaria lineata (L.) Smith (Polypodiopsida, Pteridaceae). Anatomical characterization of the leaf was carried out by light microscopy, fluorescence microscopy, and scanning electron microscopy. V. lineata possesses succulent leaves with two longitudinal furrows on the abaxial surface. We observed abundant stomata inside the furrows, glandular trichomes, paraphises, and sporangia. We examined malate concentrations in leaves, relative water content (RWC), photosynthetic pigments, and chlorophyll (Chl) a fluorescence in control, water-deficient, and...

Photosynthetic electron flow during leaf senescence: Evidence for a preferential maintenance of photosystem I activity and increased cyclic electron flow

C. Kotakis, A. Kyzeridou, Y. Manetas

Photosynthetica 2014, 52(3):413-420 | DOI: 10.1007/s11099-014-0046-5

Limitations in photosystem function and photosynthetic electron flow were investigated during leaf senescence in two field-grown plants, i.e., Euphorbia dendroides L. and Morus alba L., a summer- and winter-deciduous, shrub and tree, respectively. Analysis of fast chlorophyll (Chl) a fluorescence transients and post-illumination fluorescence yield increase were used to assess photosynthetic properties at various stages of senescence, the latter judged from the extent of Chl loss. In both plants, the yield of primary photochemistry of PSII and the content of PSI remained quite stable up to the last stages of senescence, when leaves...

Response of two tomato cultivars to field-applied proline under irrigation with saline water: Growth, chlorophyll fluorescence and nutritional aspects

B. Kahlaoui, M. Hachicha, S. Rejeb, M. N. Rejeb, B. Hanchi, E. Misle

Photosynthetica 2014, 52(3):421-429 | DOI: 10.1007/s11099-014-0053-6

The response of tomato (Solanum lycopersicum L.) to abiotic stress has been widely investigated. Recent physiological studies focus on the use of osmoprotectants to ameliorate stress damage, but experiments at a field level are scarce. Two tomato cultivars were used for an experiment with saline water (6.57 dS m^-1) and subsurface drip irrigation (SDI) in a silty clay soil. Rio Grande is a salinity-tolerant cultivar, while Heinz-2274 is the salt-sensitive cultivar. Exogenous application of proline was done by foliar spray at two concentrations (10 and 20 mg L^-1) during the flowering stage. Control plants were treated with...

Photosynthesis and ultrastructure of photosynthetic apparatus in tomato leaves under elevated temperature

J. Zhang, X. D. Jiang, T. L. Li, X. J. Cao

Photosynthetica 2014, 52(3):430-436 | DOI: 10.1007/s11099-014-0051-8

The microstructure of leaves and ultrastructure of chloroplasts were examined in tomato (Lycopersicon esculentum L.) plants treated with elevated temperature. Plants were exposed to 35°C for 30 d after florescence. The plants grown continuously under 25°C served as controls. Compared with the controls, the net photosynthetic rate (P _N) in stressed plants decreased significantly. Stomatal conductance, intercellular CO₂ concentrations, the rate of transpiration, and the limitation of stomatal conductance showed that the decrease in P _N was caused mainly by nonstomatal restrictions. Meanwhile, stomata...

Effect of NaCl and isoosmotic polyethylene glycol stress on gas exchange in shoots of the C₄ xerohalophyte Haloxylon aphyllum (Chenopodiaceae)

Z. F. Rakhmankulova, P. Yu. Voronin, E. V. Shuyskaya, N. A. Kuznetsova, N. V. Zhukovskaya, K. N. Toderich

Photosynthetica 2014, 52(3):437-443 | DOI: 10.1007/s11099-014-0048-3

The effects of NaCl (200 mM) and osmotic stress generated by polyethylene glycol (PEG) on PSII maximal quantum efficiency, photosynthetic CO₂/H₂O gas exchange at two CO₂ concentrations, content of chlorophyll, proline, and malondialdehyde were investigated in shoots of C₄ xerohalophyte Haloxylon aphyllum (Chenopodiaceae). The PEG treatment induced a low water osmotic potential (-0.4 MPa) and inhibited photosynthesis (by a factor of 2) and transpiration (by a factor of 4). The NaCl treatment, at equal osmoticity conditions, reduced transpiration (by a factor of 2) and stimulated photosynthesis (by a...

A sunny day at the beach: Ecophysiological assessment of the photosynthetic adaptability of coastal dune perennial herbs by chlorophyll fluorescence parameters

R. Bermúdez, R. Retuerto

Photosynthetica 2014, 52(3):444-455 | DOI: 10.1007/s11099-014-0049-2

Light is critical in determining plant structure and functioning in dune ecosystems, which are characterised by high incident and reflected radiation. Light variations demand great plasticity of the photosynthetic apparatus. This study assessed the phenotypic plasticity of foredune species by analysing their light response and dark recovery curves measured under field conditions. We also addressed the question how coexisting species, structurally distinct, differed in their photochemical efficiency in response to short-term changes in light. Finally, we examined how the varying intensity of stressors operating along a dune gradient affected responses...

The interacting effect of urea and fenoxaprop-P-ethyl on photosynthesis and chlorophyll fluorescence in Perilla frutescens

J. H. Zhang, S. J. Guo, P. Y. Guo, X. Wang

Photosynthetica 2014, 52(3):456-463 | DOI: 10.1007/s11099-014-0050-9

We studied the effect of herbicide and nitrogen supply on photosynthesis in Perilla frutescens L. Britt. Plants were exposed to combined treatment of urea and herbicide, fenoxaprop-P-ethyl (FPE), in various concentrations. FPE reduced significantly chlorophyll (Chl) content, photosynthetic rate, and stomatal conductance, but increased significantly intercellular CO₂ concentration; thus, FPE inhibited significantly the photosynthetic capacity. In addition, FPE also decreased significantly the PSII photochemical efficiency, effective quantum yield of photochemical energy conversion in PSII, PSII potential activity, and photochemical...

24-epibrassinolide and/or putrescine trigger physiological and biochemical responses for the salt stress mitigation in Cucumis sativus L.

Q. Fariduddin, B. A. Mir, M. Yusuf, A. Ahmad

Photosynthetica 2014, 52(3):464-474 | DOI: 10.1007/s11099-014-0052-7

Brassinosteroids (BRs) and polyamines, well-established growth regulators, play a key role in abiotic stress response in plants. In the present study, we examined the role of 24-epibrassinolide (EBL, an active BR) and/or putrescine (Put) in the salt-induced stress in cucumber. The 15-d-old plants were exposed to 100 mM NaCl and they were subsequently treated by exogenous EBL and/or Put. The salt stress reduced significantly plant growth and gas-exchange parameters, and increased proline content and electrolyte leakage in the leaves. Toxic effects induced by salt stress were completely overcome by the combination of EBL and Put. EBL and/or Put treatments...

Sodium bisulfite enhances photosynthesis in rice by inducing Rubisco activase gene expression

Y. Chen, J. H. Jin, Q. S. Jiang, C. L. Yu, J. Chen, L. G Xu, D. A. Jiang

Photosynthetica 2014, 52(3):475-478 | DOI: 10.1007/s11099-014-0044-7

To investigate how bisulfite promotes photosynthesis, a pot experiment was conducted with rice (Oryza sativa L.) plants to determine Rubisco activity and content, and Rubisco activase (RCA) gene expression after spraying NaHSO₃ on rice leaves. The NaHSO₃ treatment promoted significantly net photosynthetic rate (P _N), carboxylation efficiency, maximum carboxylation rate, ribulose-1,5-bisphosphate regeneration rate, initial Rubisco activity, and RCA protein and mRNA concentrations. Therefore, the NaHSO₃ enhancement of P _N could be directly attributed to induction of RCA gene...

Erratum to: Fitting net photosynthetic light-response curves with Microsoft Excel - a critical look at the models

F. de A. Lobo, M. P. de Barros, H. J. Dalmagro, Â. C. Dalmolin, W. E. Pereira, É. C. de Souza, G. L. Vourlitis, C. E. Rodríguez Ortíz

Photosynthetica 2014, 52(3):479-480 | DOI: 10.1007/s11099-014-0045-6