Photosynthetica, 2019 (vol. 57), issue 2

Extended temperature optimum of photosynthetic reaction centers in Rhodobacterales

D. KAFTAN, H. MEDOVÁ, V. SELYANIN, K. KOPEJTKA, M. KOBLÍŽEK

Photosynthetica 2019, 57(2):361-366 | DOI: 10.32615/ps.2019.039

Temperature is one of the most important physical factors affecting microbial and biochemical processes. We investigated the performance of photosynthetic apparatus of marine photoheterotrophic bacterium Dinoroseobacter shibae under various temperatures. The primary photochemistry and electron transport was measured using variable infra-red fluorometry in the cells grown between 8-35°C. It was found that the photosynthetic electron transport had a broad temperature optimum between 25-50°C. Moreover, the primary charge separation stayed functional even after rising temperature up to 55°C. The same phenomenon was observed also in other phototrophic...

Effects of salicylic acid on photosynthetic activity and chloroplast morphology under light and prolonged darkness

P. POÓR, P. BORBÉLY, N. BÓDI, M. BAGYÁNSZKI, I. TARI

Photosynthetica 2019, 57(2):367-376 | DOI: 10.32615/ps.2019.040

Salicylic acid (SA) is a key component of plant defence, which exerts a concentration-dependent effect on photosynthesis under multi-faceted influence of light. Photosynthetic activities and chloroplast morphology were studied in tomato plants after treatment with a sublethal, 0.1 mM, and a cell death-inducing, 1 mM concentrations of SA under normal photoperiod during light phase and after a prolonged dark phase. SA (1 mM) decreased the maximal (F_v/F_m) and effective quantum yields of PSII [Y_(II)] and PSI [Y_(I)] under both environmental conditions, however, the photoprotective processes were not significantly...

Allelopathic effects of phenolic acids on seedling growth and photosynthesis in Rhododendron delavayi Franch.

Y.H. FU, W. X. QUAN, C.C. LI, C.Y. QIAN, F.H. TANG, X.J. CHEN

Photosynthetica 2019, 57(2):377-387 | DOI: 10.32615/ps.2019.045

The effects of different concentrations of ferulic acid, chlorogenic acid, and protocatechuic acid were studied in a pot experiment to assess the response of Rhododendron delavayi seedlings. The results showed that three kinds of phenols promoted increases in chlorophyll (Chl) a, Chl b, total Chl, and carotenoid contents, but inhibited the accumulation of biomass. Low concentrations of ferulic acid significantly inhibited stomatal opening, the stomatal opening ratio, stomatal length and width. Chlorogenic acid and the moderate and high concentrations of ferulic acid also significantly inhibited stomatal density. Ferulic...

Intelligent image analysis for retrieval of leaf chlorophyll content of rice from digital images of smartphone under natural light

P. JAGAN MOHAN, S. DUTTA GUPTA

Photosynthetica 2019, 57(2):388-398 | DOI: 10.32615/ps.2019.046

The present study describes a new imaging method to acquire rice leaf images under field conditions using a smartphone and modeling approaches to retrieve the leaf chlorophyll (Chl) content from digitized images. Pearson's correlation of image-based color indices of the relative Chl content measured with Soil Plant Analysis Development (SPAD) indicated the suitability of the color models RGB, rgb, and DGCI-rgb. Among the linear regression models, the models based on mean brightness ratio (rgb) alone or in combination with a dark green color index (DGCI-rgb) show a good correlation between the predicted Chl content and relative Chl content. A...

Adaptation of photosynthesis to water deficit in the reproductive phaseof a maize (Zea mays L.) inbred line

H.F. ZHENG, L.F. XIN, J.M. GUO, J. MAO, X.P. HAN, L. JIA, B.Y. ZHENG, C.G. DU, R.W. ELMORE, Q.H. YANG, R.X. SHAO

Photosynthetica 2019, 57(2):399-408 | DOI: 10.32615/ps.2019.047

Photosynthesis is sensitive to water deficit (WD) stress. Maize (Zea mays L.) yield is vulnerable to water stress, especially if it occurs during the reproductive stage. In this study, the expression patterns of photosynthesis-related genes, together with photosynthetic gas-exchange and fluorescence parameters were investigated in a maize inbred line exposed to 50% of field water capacity (moderate WD) for 15 d after tassel emergence. The results demonstrated that WD down-regulated expression of psbA, psbB, psbC, psbP, psaA, psaB, and cab, especially at later periods of WD stress. Besides, with the increased WD stress, the steady...

The role of inoculum identity for growth, photosynthesis, and chlorophyll fluorescence of zinnia plants by arbuscular mycorrhizal fungi under varying water regimes

V. BAGHERI, M.H. SHAMSHIRI, H. ALAEI, H. SALEHI

Photosynthetica 2019, 57(2):409-419 | DOI: 10.32615/ps.2019.048

This experiment aimed to determine effects of three arbuscular mycorrhizal fungi (AMF), i.e., Rhizophagus irregularis, Rhizophagus intraradices, and Funneliformis mosseae, either singly or their mix inoculation on dry mass, photosynthesis, chlorophyll (Chl) fluorescence, leaf pigment contents, and water-use efficiency (WUE) in Zinnia elegans (var. Magellan Red) plants under different water regimes (WR). The greenhouse experiment was performed under a complete randomized design at four different WR [100% of field capacity (FC) as control, 80, 60, and 40% FC]. Our results suggested that arbuscular mycorrhizal symbiosis...

The higher area-based photosynthesis in Gossypium hirsutum L. is mostly attributed to higher leaf thickness

J.M. HAN, Y.J. ZHANG, Z.Y. LEI, W.F. ZHANG, Y.L. ZHANG

Photosynthetica 2019, 57(2):420-427 | DOI: 10.32615/ps.2019.052

There is a trade-off between leaf structures and photosynthesis physiology. While numerous reports have shown a dif- ference in photosynthesis between Gossypium hirsutum L. (upland cotton) and G. barbadense L. (pima cotton), the potential contribution of leaf structures on this difference was not fully clarified. Here, we investigated the differences in area- and mass-based photosynthetic traits and leaf structures between upland and pima cottons. Our results showed that upland cotton had higher area-based net photosynthetic rate (P_area) than that of pima cotton, which was attributed to the coordination of stomatal...

Physiological changes in winter wheat genotypes in response to the Zymoseptoria tritici infection

G. MIHAILOVA, Z. STOYANOVA, R. RODEVA, B. BANKINA, G. BIMŠTEINE, K. GEORGIEVA

Photosynthetica 2019, 57(2):428-437 | DOI: 10.32615/ps.2019.054

Some physiological aspects of interactions between wheat and Zymoseptoria tritici were studied by measuring changes in some stress markers, photosynthetic activity, and the extent of thermal energy dissipation. Four winter wheat genotypes varying in their level of resistance, determined on the basis of necrotic leaf area and presence of pycnidia, were inoculated at a seedling stage and measurements were performed at 0, 2, 17, and 23 d after the inoculation. Physiological activity of wheat genotypes showed that keeping the membrane integrity and the extent of oxidative stress is of significant importance for pathogen resistance. It could be suggested...

Seed priming with calcium chloride improves the photosynthesis performance of faba bean plants subjected to cadmium stress

I. NOUAIRI, K. JALALI, F. ZRIBI, F. BARHOUMI, K. ZRIBI, H. MHADHBI

Photosynthetica 2019, 57(2):438-445 | DOI: 10.32615/ps.2019.055

Faba bean (Vicia faba L.) seeds were treated with H₂O [nonprimed (NP)] or 2% CaCl₂ [primed (P)] before germination for 6 h. After seven days, seedlings were exposed to 0 or 50 µM CdCl₂ concentrations for three weeks. Under Cd treatment, P plants showed an improvement of gas-exchange characteristics, chlorophyll (Chl) and carotenoids contents as compared to NP plants subjected to Cd stress. Additionally, the values of Chl fluorescence were relatively similar to those of control, implying that no photodamage occurred. Moreover, under 50 µM Cd, the P plants exhibited lesser accumulation of hydrogen peroxide...

Uniconazole confers chilling stress tolerance in soybean (Glycine max L.) by modulating photosynthesis, photoinhibition, and activating oxygen metabolism system

J.J. ZHAO, N.F. FENG, X.X. WANG, G.R. CAI, M.Y. CAO, D.F. ZHENG, H.D. ZHU

Photosynthetica 2019, 57(2):446-457 | DOI: 10.32615/ps.2019.059

The current study investigates a possible mediatory role of uniconazole in improving chilling stress tolerance in chilling-sensitive (Hefeng 50) and chilling-tolerant (Kenfeng 16) soybean varieties. Chilling stress decreased photosynthetic pigments and inhibited net photosynthetic rate which was ascribed to stomatal limitation. The maximum quantum efficiency of PSII primary photochemistry and electron transport rate were lower in uniconazole-treated plants compared with the control. The increased contents of superoxide (O₂^*-) and malondialdehyde during chilling stress indicated oxidative stress. Chilling stress reduced glutathione...

Photosynthetic performance and sugar variations during key reproductive stages of soybean under potassium iodide-simulated terminal drought

D. SENGUPTA, S. MARRIBOINA, D. K. UNNIKRISHNAN, A.R. REDDY

Photosynthetica 2019, 57(2):458-469 | DOI: 10.32615/ps.2019.060

Importance of utilizing chemical desiccants to simulate terminal drought effects is gradually increasing. In the present study, a potassium iodide (KI)-simulated terminal drought stress was imposed during the full bloom (R2), pod elongation (R4), and seed initiation (R5) stages of soybean; the KI-induced desiccation effects were assessed at 1, 3, and 5 d after spraying (DASP). Plants responded to KI-simulated terminal drought stress within 1 DASP of KI-treatment, in terms of photosynthetic and transpiration rates. Seed initiation stage was found to be comparatively tolerant to KI-induced desiccation, with respect to chlorophyll degradation and PSII...

BRIEF COMMUNICATION
Photosynthetic light-response curves of light-demanding and shade-tolerant seedlings of neotropical tree species

A.K. CALZAVARA, E. BIANCHINI, J.A. PIMENTA, H.C. OLIVEIRA, R. STOLF-MOREIRA

Photosynthetica 2019, 57(2):470-474 | DOI: 10.32615/ps.2019.061

Light-response curves of seedlings of five light-demanding (LD) and four shade-tolerant (ST) neotropical tree species, native to the Brazilian Atlantic biome, were analyzed, aiming to verify differences between these functional groups regarding the light use. We hypothesized that variations in the light requirement of seedlings would occur not only between LD and ST species, but also within these functional groups. The apparent quantum yield of CO₂ assimilation, dark respiration rate (R_D), photorespiration rate (R_P), light-compensation point (I_comp), light-saturation point (I_max),...

The differential carbon-fixing and nitrogen-assimilating enzyme activities of Oscillatorian marine cyanobacterium Phormidium valderianum BDU 20041

G. DINESHBABU, V.S. UMA, M. SHYLAJANACIYAR, V. RASHMI, D. PRABAHARAN, L. UMA

Photosynthetica 2019, 57(2):475-482 | DOI: 10.32615/ps.2019.062

We have identified an efficient filamentous marine cyanobacterium, Phormidium valderianum BDU 20041, which was adaptive to different concentrations of CO₂. In our study, P. valderianum BDU 20041 was grown under ambient (0.04) and elevated (2, 3, 4, 5, 10, and 15%) CO₂ concentration. Its optimal growth occurred at 3% CO₂ supply. P. valderianum displayed similar carbon fixation activities through Rubisco, phosphoenolpyruvate carboxylase (PEPC), carbonic anhydrase, and malate dehydrogenase. The activity of Rubisco, the primary carbon-fixing enzyme, was found to be approximately 80% higher in...

Limitations to photosynthesis of leaves of apple (Malus domestica) trees across the growing season prior to and after harvest

D.H. GREER

Photosynthetica 2019, 57(2):483-490 | DOI: 10.32615/ps.2019.063

Photosynthetic responses to CO₂ were followed on leaves of Malus domestica cv. Cox's Orange trees growing in orchard conditions, before and after harvest. Rates of photosynthesis, at ambient and CO₂ saturated concentrations, were stable across the growing season, except for minor decreases at harvest although rates recovered and remained high thereafter. Stomatal conductance increased over the growing season but declined transiently just before harvest and recovered for most of the season. Rates of ribulose-1,5-bisphosphate (RuBP) carboxylation declined before harvest, however, rates of RuBP regeneration mirrored assimilation....

Phycobilisome isolation and C-phycocyanin purification from the cyanobacterium Aphanizomenon gracile

R. PIRON, T. BUSTAMANTE, A. BARRIGA, N. LAGOS

Photosynthetica 2019, 57(2):491-499 | DOI: 10.32615/ps.2019.064

Cyanobacterial phycobilisomes are made up from phycobiliproteins held together by linker proteins. Incident photons are absorbed by the phycobiliproteins that carry linear tetrapyrrole chromophores with extended conjugated bond systems. The chemical structure of the chromophores also bestows the phycobiliproteins with excellent radical scavenging and antioxidant properties and phycobiliproteins have pharmaceutical value as such. We purified and characterized the phycobilisome and its major protein constituent C-phycocyanin from the freshwater filamentous cyanobacterium Aphanizomenon gracile. Isolated phycobilisomes were shown to be intact and...

Leaf photosynthetic characteristics and photosystem II photochemistry of rice (Oryza sativa L.) under potassium-solubilizing bacteria inoculation

M. YAGHOUBI KHANGHAHI, H. PIRDASHTI, H. RAHIMIAN, G.H. NEMATZADEH, M. GHAJAR SEPANLOU, E. SALVATORI, C. CRECCHIO

Photosynthetica 2019, 57(2):500-511 | DOI: 10.32615/ps.2019.065

The current research was performed to investigate the effects of three potassium-solubilizing bacteria (KSB) strains (Pantoea agglomerans, Rahnella aquatilis, and Pseudomonas orientalis) on leaf photosynthetic characteristics in rice (Oryza sativa L. cv. Pajohesh). A pot and a field experiment were conducted in a paddy field. The results indicated that the KSB inoculums significantly enhanced chlorophyll (Chl) a, Chl a+b, SPAD value, and stomatal conductance as compared to the control in both experiments, especially when applied along with half the recommended dose of the potassium chemical fertilizer....

Effects of melatonin on photosynthesis and soybean seed growth during grain filling under drought stress

J.N. ZOU, X.J. JIN, Y.X. ZHANG, C.Y. REN, M.C. ZHANG, M.X. WANG

Photosynthetica 2019, 57(2):512-520 | DOI: 10.32615/ps.2019.066

We studied the effects of melatonin on soybean photosynthesis and seed growth at different developmental stages under drought stress induced by polyethylene glycol in the growth medium. Experimental groups were supplied with a normal nutrient solution after seven days of continuous treatment; overall, five treatments were completed when the early maturity stage was reached. Under normal water supply, melatonin supplementation had no significant effect on the photosynthetic characteristics or soybean seed growth. However, drought stress reduced leaf relative water content, chlorophyll content, and relative photosynthetic gas-exchange parameters, while...

LETTER TO THE EDITOR
The energy flux theory celebrates 40 years: toward a systems biology concept?

M. DA SILVA PONTES, R. MALDONADO RODRIGUEZ, E.F. SANTIAGO

Photosynthetica 2019, 57(2):521-522 | DOI: 10.32615/ps.2019.067

In 2018, the theory of energy fluxes in biomembranes (TEFB) developed by Professor Dr. Reto Jörg Strasser (one of the most influential leaders in the deep understanding and application of chlorophyll a fluorescence) celebrated its 40^th anniversary (Strasser 1978).

Downregulation of PSII activity and increased cyclic electron transport in cotton prevents PSI from photoinhibition due to night chilling

F. XIAO, Y.L. ZHANG, Y.L. YANG, W.F. ZHANG

Photosynthetica 2019, 57(2):523-532 | DOI: 10.32615/ps.2019.072

The objective of this experiment was to study the effects of night chilling on the photosynthetic characteristics of cotton (Gossypium hirsutum L.) at a boll-forming stage. The results suggest that overreduction of PSII after night chilling (≤ 10°C) led to excess excitation energy in cotton leaves. The night chilling (compared to 22°C) reduced PSI acceptor side limitation under moderate and high light intensity and increased maximum photooxidizable P700. This suggests that in contrast to PSII, PSI was protected from photoinhibition due to night chilling. However, PSII activity and linear electron transport were not significantly affected...

Depletion of extracellular ATP affects the photosystem II photochemistry and the role of salicylic acid in this process

Q.Z. HOU, X. PANG, K. SUN, J.Y. LIANG, L.Y. JIA, H.Q. FENG, T.S. ZHANG, Y.D. ZHENG, Y.P. WANG

Photosynthetica 2019, 57(2):533-539 | DOI: 10.32615/ps.2019.077

In the present work, treatment with AMP-PCP (β,γ-methyleneadenosine-5'-triphosphate - a competitive inhibitor of the extracellular ATP pool) or apyrase (an ATP-degrading enzyme) decreased the PSII operating efficiency (Φ_PSII), photochemical quenching (q_p), and maximum quantum efficiency of PSII photochemistry (F_v/F_m) of Arabidopsis leaves illuminated with high light intensity. Mutation of extracellular ATP receptor, DORN1, also caused decreases of Φ_PSII, q_p, and F_v/F_m when the leaves were exposed to high light. Either the treatment with...

Can needle nitrogen content explain the interspecific difference in ozone sensitivities of photosynthesis between Japanese larch (Larix kaempferi) and Sakhalin fir (Abies sachalinensis)?

T. SUGAI, M. KITAO, T. WATANABE, T. KOIKE

Photosynthetica 2019, 57(2):540-547 | DOI: 10.32615/ps.2019.042

Although deciduous and evergreen conifers are expected to utilize needle nitrogen differently, their interspecific differences in the ozone sensitivity remain unclear. We compared the growth and physiological responses to elevated O₃ concentrations in deciduous Japanese larch (Larix kaempferi) and evergreen Sakhalin fir (Abies sachalinensis) seedlings. Seedlings of both species were exposed to 62.5 ± 1.95 nmol(O₃) mol^-1 during the day time in open-top chambers. Elevated O₃ had no effect on height or diameter growth in either of the species but suppressed photosynthetic parameters. A decline...

Leaf traits and photosynthetic characteristics of endangered Sinopodophyllum hexandrum (Royle) Ying under different light regimesin Southeastern Tibet Plateau

Q.Q. GUO, H.E. LI, C. GAO, R. YANG

Photosynthetica 2019, 57(2):548-555 | DOI: 10.32615/ps.2019.080

Sinopodophyllum hexandrum (Royle) Ying, a medicinal plant, has been endangered due to alpine habitat and overuse at Southeastern Tibet Plateau. This study aimed to examine the phenotypic traits and photosynthesis of S. hexandrum, including their relationship with main environmental factors, under low light (LL), moderate light (ML), and high light (HL) regimes. Low specific leaf mass was observed under LL, but the stomatal density and apparent quantum yield were the highest under this regime. The phenotypic traits, except for stomatal density and net photosynthetic rate, were the most notable under ML. The leaf area, stomatal density,...

The effect of light quality on the expression of stomatal development genes of maize

T.D. LIU, X.W. ZHANG, Y. XU

Photosynthetica 2019, 57(2):556-563 | DOI: 10.32615/ps.2019.082

Light-induced stomatal development is mediated through a crosstalk between cryptochrome (CRY), phytochrome (phy), and constitutive photomorphogenic 1 (COP1)-signaling systems. In maize, crosstalk is a complicated phenomenon that is accomplished by COP1-signaling pathway. Epidermal patterning factor 2 (EPF2) and epidermal patterning factor-like 9 (EPFL9)-regulated path signals rely on CRY and phy under blue and red light, respectively. Our experimental results showed that, in maize, ZmCOP1 expressed downstream CRY under monochromatic blue light. Blue light, which induced ZmEPF2 expression, was restricted, thereby increasing stomatal formation...

Effect of salt stress on the growth and photosystem II photochemical characteristics of Lycium ruthenicum Murr. seedlings

Y.-Y. GUO, H.-S. NIE, H.-Y. YU, D.-S. KONG, J.-Y. WU

Photosynthetica 2019, 57(2):564-571 | DOI: 10.32615/ps.2019.068

The present study aimed to determine effects of salt stress on Lycium ruthenicum Murr. seedlings. Our results showed that mild and moderate salt stress were beneficial to L. ruthenicum seedling growth. Minimal fluorescence increased and maximum fluorescence decreased gradually with the increasing levels of salt stress. Absorption flux per reaction center (RC), trapped energy flux per RC, and trapped energy flux per optical cross section (CS) increased significantly, while electron transport flux per CS decreased with salt stress duration and rising salt concentration. During salt stress, there was a gradual decline in probability that...

Distribution and effects of ionic titanium application on energy partitioning and quantum yield of soybean under different light conditions

S. HUSSAIN, N. IQBAL, M.A. RAZA, M.N. KHAN, S. AHMED, T. RAHMAN, P. CHEN, X. WANG, X. DU, W. LIU, W. YANG

Photosynthetica 2019, 57(2):572-580 | DOI: 10.32615/ps.2019.074

Soybean growth and development response to ionic titanium application have never been investigated. Therefore, such study is needed to better explain the titanium (Ti) application for soybean crop. For the first time, we studied the effects of application of two Ti concentrations (12.5 and 25 mg L^-1) on photosynthetic and chlorophyll (Chl) fluorescence parameters of soybean under normal light (NL) and shade conditions (SC). Compared to NL, SC significantly decreased Chl contents, leaf area (LA), leaf thickness (LT), plant dry mater (PDM), photosynthetic and Chl fluorescence parameters, total soluble sugar, and Ti uptake. Overall, Ti application...

Effects of nitrogen supply on the photosynthetic capacity of the hybrid citrus cultivar 'Huangguogan'

L. LIAO, J.L. FU, T.T. DONG, X. QIU, Y. RONG, X.Y. LIU, Z.X. DONG, G.C. SUN, Z.H. WANG

Photosynthetica 2019, 57(2):581-589 | DOI: 10.32615/ps.2019.083

Pot experiments were conducted to determine the effects of nitrogen (N) fertilization rate on the photosynthetic efficiency of 'Huangguogan' (Citrus reticulata × Citrus sinensis). We observed that plant growth increased with increasing N. Maximum values for parameters evaluated were recorded for an N addition rate of 120 g per year. Leaf chlorophyll content was positively correlated with the leaf N content. The relative reduction in photosynthetic rate (P_N) at high N (150 and 180 g) correlated with the parallel decreases in the leaf N content. Rubisco activity was positively correlated with the initial slope of the...

Acetylcholine mechanism of action to enhance tolerance to salt stress in Nicotiana benthamiana

C. QIN, Y.Y. SU, B.S. LI, Y.Q. CHENG, C.C. WEI, S. YUAN, N. AHMED, M. ASHRAF, L.X. ZHANG

Photosynthetica 2019, 57(2):590-598 | DOI: 10.32615/ps.2019.084

Acetylcholine (ACh) is one of the important neurotransmitters, involved in signal transduction function in human and animal brain. However, the influence of ACh treatment on salt-stress tolerance in plants is yet unknown. Salt stress caused a reduction in gas-exchange parameters, chlorophyll content, antioxidant enzyme activities, and leaf relative water content of Nicotiana benthamiana plants. However, the above inhibitions could be significantly alleviated by application of leaf spray or root application of ACh. Exogenous ACh reduced the accumulation of malondialdehyde by enhancing activities of antioxidant enzymes such as peroxidase and superoxide...

Efficacy of TiO₂ nanoparticles in enhancing the photosynthesis, essential oil and khusimol biosynthesis in Vetiveria zizanioides L. Nash

A. SHABBIR, M.M.A. KHAN, B. AHMAD, Y. SADIQ, H. JALEEL, M. UDDIN

Photosynthetica 2019, 57(2):599-606 | DOI: 10.32615/ps.2019.071

Titanium dioxide nanoparticles (TiO₂NPs) have intrigued scientists due to their plant growth elicitor activity and potential to strengthen the photosynthetic machinery of plants. Therefore, we investigated if foliar application of TiO₂NPs could enhance the photosynthetic characteristics and the yield of essential oil-bearing multi-purpose crop, Vetiveria zizanioides. Of the various concentrations (30, 60, 90, 120, and 150 mg L^-1), 90 mg(TiO₂NPs) L^-1 was found being significant enough in mproving most of the parameters studied. At 300 d after transplantation, foliar application of TiO₂NPs...

Dorsoventral regulation of photosynthetic functions related to morphological and anatomical structures in field-grown sorghum

X. WANG, Y. SHI, Q. WANG, Y. LI

Photosynthetica 2019, 57(2):607-616 | DOI: 10.32615/ps.2019.085

The rapid dorsoventral regulation of photosynthesis is important because the light conditions around both surfaces of field-grown leaves vary considerably. The photosynthetic asymmetry has been intensively studied, but structure-related explanations for asymmetry were not exactly clarified. This study aimed to investigate the photosynthetic asymmetry in field-grown Sorghum bicolor L. and analyze the impacts of dorsoventral structures on photosynthesis. We found that the photosynthetic asymmetry changed with light conditions, and adaxial surfaces had higher primary photochemical activity owing to higher mesophyll density, while abaxial surfaces...

Photoinhibition and continuous growth of the wild-type and a high-light tolerant strain of Chlamydomonas reinhardtii

O. VIRTANEN, D. VALEV, O. KRUSE, L. WOBBE, E. TYYSTJÄRVI

Photosynthetica 2019, 57(2):617-626 | DOI: 10.32615/ps.2019.056

The volumetric productivity of the high-light tolerant strain hit2 of Chlamydomonas reinhardtii was found to be higher than that of the parental strain CC124 during continuous growth at PPFD from 200 to 1,500 µmol m^-2 s^-1. At PPFD of 1,250 µmol m^-2 s^-1, hit2 produced 2.53 ± 0.18 and CC124 produced 2.05 ± 0.12 g(biomass) dm^-3 d^-1. The rate constant of photoinhibition of hit2 was less than half of that of CC124, suggesting that hit2 produces more biomass than CC124 because hit2 does not need...

Responses of photosynthetic apparatus in sunflower cultivars to combined drought and salt stress

M. UMAR, Z. UDDIN, Z.S. SIDDIQUI

Photosynthetica 2019, 57(2):627-639 | DOI: 10.32615/ps.2019.043

Response of photosynthetic apparatus in some sunflower cultivars, i.e., S.28111, Hysun-33, Hysun-39, and SF0049, to salt, drought, and combined stresses were studied. The combined stress caused severe damage to photosynthetic apparatus as compared to single stress. The maximum quantum yield of PSII, phenomenological fluxes, plastoquinone pool size, performance indexes, and driving force of absorption were greatly affected by the combined stress. Among the cultivars, the combined stress produced synergistic effect (greater damage) in Hysun-33 and cross-tolerance (lesser damage) in S.28111. Similarly, concerning the ion imbalance, S.28111 and...

The effect of potassium on photosynthetic acclimation in cucumber during CO₂ enrichment

X. DABU, S. LI, Z. CAI, T. GE, M. HAI

Photosynthetica 2019, 57(2):640-645 | DOI: 10.32615/ps.2019.073

Long-term CO₂ enrichment (1,000 μmol mol^-1) leads to photosynthetic acclimation in cucumber. Here, through hydroponic experiments in an open-top climate chamber system, we investigated key photosynthetic parameters of cucumbers using potassium stimulation (120 or 240 mg L^-1). Short-term CO₂ enrichment (less than 25 days) significantly increased the net photosynthetic rate in cucumber. However, long-term CO₂ enrichment (43 d) led to photosynthetic acclimation and decrease in stomatal conductance. The increase in potassium alleviated the decrease in photosynthetic rate and stomatal conductance,...

JIP-test in assessing sensitivity to nitrogen deficiency in two cultivars of Actinidia arguta (Siebold et Zucc.) Planch. ex Miq.

T. SWOCZYNA, B. ŁATA, A. STASIAK, J. STEFANIAK, P. LATOCHA

Photosynthetica 2019, 57(2):646-658 | DOI: 10.32615/ps.2019.057

Optimal nitrogen availability is necessary to keep high photosynthetic efficiency and in consequence, good physiological condition and growth of plants. In order to examine the effect of N nutrition on photosynthetic apparatus performance we used the chlorophyll a fluorescence (ChF) technique in two differing Actinidia cultivars and we aimed to select the most reliable ChF parameters showing N deficiency. The 4-years-old specimens growing on an experimental plantation were treated with three differing N doses and ChF data were collected during two years. The results showed that PSII performance indices, performance index on the absorption...

Photosynthetic activity of red and green leaf sectors in Coleus blumei plants as sensed by chlorophyll fluorescence

K.H. LIN, M.Y. HUANG, J.H. WENG, S.C. KAO

Photosynthetica 2019, 57(2):659-667 | DOI: 10.32615/ps.2019.051

The changes and responses in the chlorophyll (Chl) fluorescence (ChlF) components were studied on the red and green parts of leaves in three Coleus blumei varieties under different light intensities. Chl a, carotenoids (Car), and SPAD were linearly, positively, and significantly correlated with total Chl [i.e., Chl (a+b)] of red and green leaves. Significant differences in Chl and Car contents were noted between differentially pigmented sectors of the leaf, but no anthocyanin content was found in the green parts compared to red leaves. Values of minimal and maximal fluorescence yields in dark- and light-adapted states...

Discovering trends in photosynthesis using modern analytical tools:More than 100 reasons to use chlorophyll fluorescence

W. BĄBA, A. KOMPAŁA-BĄBA, M. ZABOCHNICKA-ŚWIĄTEK, J. LUŹNIAK, R. HANCZARUK, A. ADAMSKI, H.M. KALAJI

Photosynthetica 2019, 57(2):668-679 | DOI: 10.32615/ps.2019.069

In this review, using the network analysis, based on the bibliometric data, collected from Web of Science Core Collection database, we followed the development of chlorophyll fluorescence research (CFR) during 1947-2018. We confirmed dramatic increase in diversity of CFR from late 90-ties and vigorous development of this discipline in the last ten years. They are parallel to an increase in number of research areas and institutions involved and were triggered by the accumulation of knowledge and methodological, technological, and communication advances, especially modern fluorimeters and fluorescence techniques. The network analysis of keywords...

The mechanism of starch content increase in grain of autotetraploid rice (Oryza sativa L.)

P.M. YANG, X.R. ZHOU, Q.C. HUANG

Photosynthetica 2019, 57(2):680-687 | DOI: 10.32615/ps.2019.044

Net photosynthetic rate (P_N), photorespiration (P_R), chlorophyll (Chl) content, Chl fluorescence parameters, starch accumulation, and related key enzyme activities were determined during the grain-filling stage in two autotetraploid lines and corresponding diploid rice lines. The results showed that autotetraploid rice lines had a higher Chl content, P_N, electron transport rate, maximum photochemical efficiency of PSII, actual photochemical efficiency of PSII, and lower P_R in leaves than that in corresponding diploid rice lines during the grain-filling stage. It indicated that...

Effects of Pb and Zn toxicity on chlorophyll fluorescence and biomass production of Koelreuteria paniculata and Zelkova schneideriana young plants

X.H. HUANG, F. ZHU, W.D. YAN, X.Y. CHEN, G.J. WANG, R.J. WANG

Photosynthetica 2019, 57(2):688-697 | DOI: 10.32615/ps.2019.050

The influence of Pb and Zn on chlorophyll (Chl) fluorescence and plant growth of one-year-old Koelreuteria paniculata and Zelkova schneideriana young plants was investigated. Pb and Zn contents in plant organs were measured. The results showed Pb and Zn stress decreased photochemical quenching and quantum efficiency of PSII, but increased energy dissipation in the tested plants. At the same time, maximum net photosynthetic rate, maximum quantum use efficiency, and organ biomass were reduced. Under the same concentration of heavy metals, the damage induced by Zn toxicity was more serious than that of Pb. Pb was less accumulated in leaves,...

Relationship between photosynthesis, bleeding-sap mass, and bleeding components in maize hybrids and corresponding parents in northern China

Z. HE, C. XU, B. LIU, B. YAO, H. WANG, Z.Y. CHEN, D.Y. LI, Z.Y. BAI, Z.A. ZHANG

Photosynthetica 2019, 57(2):698-704 | DOI: 10.32615/ps.2019.096

Currently, the main maize production areas in northeastern China are facing soil fertility loss, which severely affects root growth and limits photosynthesis. It is widely acknowledged that physiological conditions of the root system are closely related to the photosynthetic capacity; therefore, we evaluated whether there are certain differences in root bleeding sap characteristics and photosynthetic capacity between the hybrids and their parents. The results showed that heterosis of the photosynthetic capacity occurred at the milk-ripe stage; however, heterosis of bleeding-sap mass (BSM) and organic biomass occurred during the whole growth period....

The density of barnyard grass affects photosynthesis and physiological characteristics of rice

X.L. WANG, Z.Y. ZHANG, X.M. XU, G. LI

Photosynthetica 2019, 57(2):705-711 | DOI: 10.32615/ps.2019.075

Barnyard grass (Echinochloa crus-galli) is a troublesome graminaceous weed infesting rice fields in the Yangtze River Basin, China. However, the effects of barnyard grass on rice root physiology are unclear. In this study, the effects of barnyard grass, planted at different densities (ranging from 2-8 plants m^-2), on rice performance were evaluated, including chlorophyll fluorescence parameters, Rubisco activity, root oxidation activity, and the zeatin + zeatin riboside concentration. The results indicated that rice photosynthesis and physiological characteristics decreased as the density of barnyard grass increased. The rice net...

LETTER TO THE EDITOR
Inclusion of photoprotective parameters in photosynthesis-measuring systems to improve the interpretation of photosynthesis and productivity

C.C. OGBAGA, H.U.R. ATHAR

Photosynthetica 2019, 57(2):712-713 | DOI: 10.32615/ps.2019.041

While reading the paper by Vredenberg (2018) published in Photosynthetica (10 January, 2018), I was inspired to write this letter.