Editorial

Helena Synková, Ivana Štětinová

Photosynthetica 2014, 52(1):1-2 | DOI: 10.1007/s11099-014-0017-x  

Leaf gas exchange in species of the Theobroma genus

A. A. F. Almeida, F. P. Gomes, R. P. Araujo, R. C. Santos, R. R. Valle

Photosynthetica 2014, 52(1):16-21 | DOI: 10.1007/s11099-013-0048-8  

Species of the Theobroma genus are primarily known by their commercially valuable seeds, especially, T. cacao is one of the most important tropical perennial crops. Beside T. grandiflorum, T. bicolor, and T. angustifolium, T. cacao is the only species of the genus that has been better studied to obtain physiologically relevant information. The main objective of this work was to evaluate the leaf gas exchange in seedlings of seven species of the Theobroma genus, seeking to identify characteristics that could be used in T. cacao breeding programmes. The study was realized under greenhouse conditions using...

The physiological light response of two tree species across a hydrologic gradient in Brazilian savanna (Cerrado)

H. J. Dalmagro, F. de A. Lobo, G. L. Vourlitis, Â. C. Dalmolin, M. Z. Antunes Jr., C. E. R. Ortíz, J. de S. Nogueira

Photosynthetica 2014, 52(1):22-35 | DOI: 10.1007/s11099-014-0001-5  

Tropical savanna ecosystems are extremely diverse and important for global carbon storage. In the state of Mato Grosso, tropical savanna (locally known as the Cerrado), turns from well-drained, upland areas into seasonally flooded areas within the Pantanal; however, the Cerrado and the Pantanal share many common tree species, such as Vochysia divergens, a flood-adapted tree native to the Amazon Basin, and Curatella americana, a tree, adapted native to the welldrained the Cerrado. We measured the photosynthetic light response of these species in the the Cerrado and the Pantanal over a 1-year period to determine how these species physiologically...

Photosynthesis of two moss crusts from the Tengger Desert with contrasting sensitivity to supplementary UV-B radiation

R. Hui, X. R. Li, R. L. Jia, L. C. Liu, R. M. Zhao, X. Zhao, Y. P. Wei

Photosynthetica 2014, 52(1):36-49 | DOI: 10.1007/s11099-014-0003-3  

Predicting the effects of increased ultraviolet-B (UV-B) radiation due to stratospheric ozone depletion on temperate desert ecosystems requires better knowledge of the ecophysiological response of common moss species. The aim of the current work was to determine whether elevated UV-B radiation affected photosynthetic performance and chloroplast ultrastructure of two moss crusts and whether response differences were observed between the crusts. In laboratory experiments, Bryum argenteum and Didymodon vinealis, which show microdistributions and are dominant in soil crusts at the Tengger Desert, Northern China, were subjected to four levels...

Acclimation and photoprotection of young gametophytes of Acrostichum danaeifolium to UV-B stress

A. M. Randi, M. C. A. Freitas, A. C. Rodrigues, M. Maraschin, M. A. Torres

Photosynthetica 2014, 52(1):50-56 | DOI: 10.1007/s11099-014-0006-0  

The effect of ultraviolet B radiation (UV-B) on cellular ultrastructure, chlorophyll (Chl), carotenoids, and total phenolics of Acrostichum danaeifolium gametophytes was analyzed. The control group of spores was germinated under standard conditions, while the test group of spores was germinated with additional UV-B for 30 min every day for 34 d. The cell characteristics were preserved in gametophytes irradiated with UV-B, but the number of starch grains increased in the chloroplasts and the more developed grana organization in contrast to the chloroplasts of the control group. Chl a content decreased, while Chl b content increased...

Application of chlorophyll fluorescence to screen eggplant (Solanum melongena L.) cultivars for salt tolerance

S. Hanachi, M. C. Van Labeke, T. Mehouachi

Photosynthetica 2014, 52(1):57-62 | DOI: 10.1007/s11099-014-0007-z  

The objective of this study was to investigate the relative salt tolerance of four eggplant cultivars (Solanum melongena L.) by studying chlorophyll (Chl) fluorescence parameters during the vegetative growth stage under increasing salinity levels. The plants were grown in pots filled with peat under controlled conditions and were subjected to the salt stress ranging from 0 (control), 20, 40, 80, and 160 mM NaCl for 25 days. The results showed that the increasing NaCl concentration affected hardly the maximum quantum yield of photosystem (PS) II. The quantum yield of PSII (Φ_PSII) decreased significantly in 'Adriatica' and 'Black...

Interactive effects of elevated CO₂ and drought on photosynthetic capacity and PSII performance in maize

Y. Z. Zong, W. F. Wang, Q. W. Xue, Z. P. Shangguan

Photosynthetica 2014, 52(1):63-70 | DOI: 10.1007/s11099-014-0009-x  

Elevated atmospheric CO₂ concentration [CO₂] and the change of water distribution in arid and semiarid areas affect plant physiology and ecosystem processes. The interaction of elevated [CO₂] and drought results in the complex response such as changes in the energy flux of photosynthesis. The performance of photosystem (PS) II and the electron transport were evaluated by using OJIP induction curves of chlorophyll a fluorescence and the P _N-C _i curves in the two-factor controlled experiment with [CO₂] of 380 (AC) or 750 (EC) [μmol mol^-1] and water stress...

Physiological response of wheat varieties to elevated atmospheric CO₂ and low water supply levels

S. Bencze, Z. Bamberger, T. Janda, K. Balla, B. Varga, Z. Bedő, O. Veisz

Photosynthetica 2014, 52(1):71-82 | DOI: 10.1007/s11099-014-0008-y  

In the phytotron experiment, the effect of elevated atmospheric CO₂ (EC, 750 μmol mol^-1) on the drought tolerance was studied in two winter varieties (Mv Mambo, tolerant; Mv Regiment, moderately tolerant) and in one spring variety of wheat (Lona, sensitive to drought). Changes in net photosynthetic rate (P _N), stomatal conductance, transpiration, wateruse efficiency, effective quantum yield of photosystem II, and activities of glutathione reductase (GR), glutathione-Stransferase (GST), guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were monitored during water withdrawal. Drought...

Molecular characteristics and expression patterns of Rubisco activase, novel alternative splicing variants in a heterophyllous aquatic plant, Sagittaria graminea

D. Wang, S. Z. Xie, J. Yang, Q. F. Wang

Photosynthetica 2014, 52(1):83-95 | DOI: 10.1007/s11099-014-0013-1  

Two full-length cDNAs (SGrca1 and SGrca2) encoding ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) were cloned from a heterophyllous aquatic plant, Sagittaria graminea, using Rapid-Amplification of cDNA Ends (RACE). SGrca1 contains a 1,320 bp open reading frame encoding a protein of 440 amino acids, and SGrca2 is exactly identical to SGrca1 except for 330 bp missing in the middle of SGrca1. Sequence analysis of cDNA and genomic DNA indicated both two cDNAs were generated from a common gene via alternative splicing. The deduced amino acid sequence encoded by SGrca1...

24-epibrassinolide improves cucumber photosynthesis under hypoxia by increasing CO₂ assimilation and photosystem II efficiency

Y. H. Ma, S. R. Guo

Photosynthetica 2014, 52(1):96-104 | DOI: 10.1007/s11099-014-0010-4  

Seedlings of the hypoxia-sensitive cucumber cultivar were hydroponically grown under hypoxia for 7 d in the presence or absence of 24-epibrassinolide (EBR, 2.1 nM). Hypoxia significantly inhibited growth, while EBR partially counteracted this inhibition. Leaf net photosynthetic rate (P _N), stomatal conductance, transpiration rate, and water-use efficiency declined greatly, while the stomatal limitation value increased significantly. The maximum net photosynthetic rate was strongly reduced by hypoxia, indicating that stomatal limitation was not the only cause of the P _N decrease. EBR markedly diminished the harmful...

Response of photosynthesis and chlorophyll fluorescence to acute ozone stress in tomato (Solanum lycopersicum Mill.)

A. A. Thwe, G. Vercambre, H. Gautier, F. Gay, J. Phattaralerphong, P. Kasemsap

Photosynthetica 2014, 52(1):105-116 | DOI: 10.1007/s11099-014-0012-2  

The crop sensitivity to ozone (O₃) is affected by the timing of the O₃ exposure, by the O₃ concentration, and by the crop age. To determine the physiological response to the acute ozone stress, tomato plants were exposed to O₃ at two growth stages. In Experiment I (Exp. I), O₃ (500 μg m^-3) was applied to 30-d-old plants (PL30). In Experiment II (Exp. II), three O₃ concentrations (200, 350, and 500 μg m^-3) were applied to 51-d-old plants (PL51). The time of the treatment was 4 h (7:30-11:30 h). Photosynthesis and chlorophyll fluorescence measurements were done...

A modified nonrectangular hyperbola equation for photosynthetic light-response curves of leaves with different nitrogen status

J. Z. Xu, Y. M. Yu, S. Z. Peng, S. H. Yang, L. X. Liao

Photosynthetica 2014, 52(1):117-123 | DOI: 10.1007/s11099-014-0011-3  

Chlorophyll index and leaf nitrogen status (SPAD value) was incorporated into the nonrectangular hyperbola (NRH) equation for photosynthetic light-response (PLR) curve to establish a modified NRH equation to overcome the parameter variation. Ten PLR curves measured on rice leaves with different SPAD values were collected from pot experiments with different nitrogen (N) dosages. The coefficients of initial slope of the PLR curve and the maximum net photosynthetic rate in NRH equation increased linearly with the increase of leaf SPAD. The modified NRH equation was established by multiplying a linear SPAD-based adjustment factor with the NRH equation....

Photosynthetic response of poikilochlorophyllous desiccation-tolerant Pleurostima purpurea (Velloziaceae) to dehydration and rehydration

S. T. Aidar, S. T. Meirelles, R. F. Oliveira, A. R. M. Chaves, P. I. Fernandes-Júnior

Photosynthetica 2014, 52(1):124-133 | DOI: 10.1007/s11099-014-0014-0  

The poikilochorophyllous, desiccation-tolerant (PDT) angiosperm, Pleurostima purpurea, normally occurs in less exposed rock faces and slightly shady sites. Our aim was to evaluate the light susceptibility of the photosynthetic apparatus during dehydration-rehydration cycle in P. purpurea. In a controlled environment, the potted plants were subjected to water deficit under two different photosynthetic photon flux densities [PPFD, 100 and 400 μmol(photon) m^-2 s^-1]. In the higher PPFD, net photosynthetic rate (P _N) become undetectable after stomata closure but photochemical efficiency of photosystem...

Growth, photosynthesis and ion balance of sesame (Sesamum indicum L.) genotypes in response to NaCl concentration in hydroponic solutions

A. H. Bazrafshan, P. Ehsanzadeh

Photosynthetica 2014, 52(1):134-147 | DOI: 10.1007/s11099-014-0015-z  

A hydroponic, greenhouse experiment was conducted to assess the effects of NaCl on growth, gas-exchange parameters, chlorophyll (Chl) content, and ion distribution in seven sesame (Sesamum indicum L.) genotypes (Ardestan, Varamin, Naz-Takshakhe, Naz-Chandshakhe, Oltan, Yekta, Darab). The plants were grown in 4-L containers and subjected to varying levels of salinity (0, 30, and 60 mM NaCl). After 42 days, salt treatments induced decreases of plant fresh and dry mass, total leaf area, and plant height in all genotypes. Increasing NaCl concentration caused significant, genotypedependent decrease in the net photosynthetic rate, stomatal conductance,...

Contribution of stem CO₂ fixation to whole-plant carbon balance in nonsucculent species

E. Ávila, A. Herrera, W. Tezara

Photosynthetica 2014, 52(1):3-15 | DOI: 10.1007/s11099-014-0004-2  

In many plant species that remain leafless part of the year, CO₂ fixation occurring in green stems represents an important carbon gain. Traditionally, a distinction has been made between stem photosynthesis and corticular photosynthesis. All stem photosynthesis is, sensu stricto, cortical, since it is carried out largely by the stem cortex. We proposed the following nomenclature: stem net photosynthesis (SNP), which includes net CO₂ fixation by stems with stomata in the epidermis and net corticular CO₂ fixation in suberized stems, and stem recycling photosynthesis (SRP), which defines CO₂ ling in suberized...

Different responses of young and expanded lettuce leaves to fungicide Mancozeb: chlorophyll fluorescence, lipid peroxidation, pigments and proline content

M. C. Dias, P. Figueiredo, I. F. Duarte, A. M. Gil, C. Santos

Photosynthetica 2014, 52(1):148-151 | DOI: 10.1007/s11099-014-0016-y  

This work aimed to study the effects of commercial doses of the fungicide, Mancozeb, on the photosynthetic apparatus of lettuce young leaves (YL) and expanded leaves (EL). Seven days after Mancozeb application, chlorophyll a fluorescence, pigment contents, lipid peroxidation, and proline content were evaluated. Independently of leaf age, Mancozeb treatment reduced the efficiency of photosystem II photochemistry, increased the nonphotochemical quenching and proline content, decreased pigment contents, and induced lipid peroxidation. Moreover, EL showed a more stable photosynthetic apparatus, less prone to oxidative damages compared with YL. The...

Effects of exogenous hormones on leaf photosynthesis of Panax ginseng

X. Li, K. Xu

Photosynthetica 2014, 52(1):152-156 | DOI: 10.1007/s11099-014-0005-1  

Ginseng (Panax ginseng) is a typical perennial shade plant. Aim of this study was to investigate the effects of exogenous hormones on photosynthesis of P. ginseng. At different growth stages, the aerial parts of P. ginseng plants were cut at the stem base and they were inserted into the nutrient solutions containing different exogenous hormones. Then the leaf photosynthesis and water absorbing capacity (absorbing water mass) of the excised plants were measured. The results showed that exogenous abscisic acid (ABA) decreased significantly net photosynthetic rate (P _N), stomatal conductance, transpiration rate,...

Photosynthesis, photosystem II efficiency, amino acid metabolism and ion distribution in rice (Oryza sativa L.) in response to alkaline stress

Z. H. Wu, C. W. Yang, M. Y. Yang

Photosynthetica 2014, 52(1):157-160 | DOI: 10.1007/s11099-014-0002-4  

Alkalies are important agricultural contaminants complexly affecting plant metabolism. In this study, rice seedlings were subjected to alkaline stress (NaHCO₃:Na₂CO₃ = 9:1; pH 8.9) for 30 days. The results showed that stress mightily reduced net photosynthetic rate (P _N), but slightly decreased transpiration rate and stomatal conductance. This indicated that decline of P _N might be a result of nonstomatal factors. Alkaline stress caused a large accumulation of Na⁺ in leaves up to toxic concentration, which possibly affected chloroplast ultrastructure and photosynthesis....