Tartary buckwheat (Fagopyrum tataricum Gaertn) has been praised as one of green foods for humans in the 21st century. Effects of fertilization on leaf photosynthetic characteristics and grain yield of tartary buckwheat has not been yet reported in detail. Our experiment was set as a split-plot factorial. The main plots and subplots were designed by fertilizer ratio and rate as: NPK 1:1:1 (A1), NPK 1:4:2 (A2), NPK 1:2:3 (A3), and 300 (B1), 450 (B2), and 600 (B3) kg (NPK) ha-1. Our results showed that the grain yield was significantly and positively correlated with the net photosynthetic rate (PN), stomatal conductance (gs), transpiration rate (E), PAR, stomatal limitation value (Ls), chlorophyll content (SPAD value), and leaf area index (LAI), while significantly and negatively correlated with intercellular CO2 concentration (Ci) and water-use efficiency (WUE). The grain yield, PN, gs, E, PAR, Ls, SPAD, and LAI increased and then decreased with enhanced fertilization, and their maximum values appeared in the A2B2 treatment. The Ci and WUE decreased and then increased with enhanced fertilization, and their minimum values appeared in the A2B2 treatment. Our results suggested that fertilization had significant effects on the leaf photosynthetic capacity and grain yield of tartary buckwheat
Yunqiao1, and the best fertilization strategy was 450 kg ha-1 with NPK 1:4:2., C. Wang, H. Z. She, X. B. Liu, D. Hu, R. W. Ruan, M. B. Shao, L. Y. Zhang, L. B. Zhou, G. B. Zhang, D. Q. Wu, Z. L. Yi., and Obsahuje bibliografii
We carried out a field experiment in order to study effects of fertilization in juvenile plants of three coffee (Coffea arabica) cultivars in Yunnan, SW China. Fertilization treatments included a control without fertilizer (CK), combinations of three NPK fertilization rates [high fertilization (FH), medium fertilization (FM), and low fertilization (FL) with 135, 90, and 45 g per plant per year, respectively], and at two N:P2O5:K2O ratios (R1, 1:0.5:0.8; R2, 1:0.8:0.5). The growth in juvenile plants was not altered by fertilization, with two clear growth peaks being observed in both the height and stem growth rates (RGRs) throughout a year. Both FM and FH resulted in significantly higher RGRs in both height and stem diameter compared to FL and CK in all three cultivars. At the same fertilization rate, the leaf area, branch number, longest branch length, internode number, and biomass of R2 were higher than those of R1, and P significantly affected the root biomass and root to shoot ratio. Compared to the FL treatment, both FM and FH treatments resulted in higher net photosynthetic rates and stomatal conductance across seasons, and in higher intrinsic water-use efficiency during the dry season and at the middle of the wet season. Photosynthetic nitrogen-use efficiency at R2 was higher than that at R1, but no significant differences were observed between the different fertilization rates. Among the three coffee cultivars, Caturra exhibited the highest height, stem diameter, longest branch length, and internode number. Our results indicated that the optimal N:P2O5:K2O ratio was 1:0.8:0.5 for the juvenile growth of coffee plants. Both FM and FH could help optimize the growth and photosynthetic rate of coffee plants, but FM is suitable for the ecological friendly agriculture and economic sustainability at coffee plantations., Z. X. Zhang, Z. Q. Cai, G. Z. Liu, H. Wang, L. Huang, C. T. Cai., and Obsahuje bibliografii
The effects of exogenous sodium nitroprusside (SNP), as nitric oxide donor, and spermidine (Spd) on growth and photosynthetic characteristics of Bakraii seedlings (Citrus reticulata x Citrus limetta) were studied under NaCl stress. In citrus plants, SNP- and Spd-induced growth improvement was found to be associated with reduced electrolyte leakage, malondialdehyde, hydrogen peroxide content, and leaf Na+ and Cl- concentration. However, we found increased leaf Ca2+, Mg2+, and K+ concentrations, relative water content, chlorophyll fluorescence parameters, antioxidant enzyme activities, such as ascorbate peroxidase, catalase, superoxide dismutase and peroxidase, as well as higher photosynthetic rate, intercellular CO2 concentration, stomatal conductance, and transpiration rate under saline regime. Foliar application of SNP and Spd alone mitigated the adverse effect of salinity, while the combined application proved to be even more effective., D. Khoshbakht, M. R. Asghari, M. Haghighi., and Obsahuje bibliografii
The objective of this study was to investigate the effect of elevated (550 ± 17 μmol mol-1) CO2 concentration ([CO2]) on leaf ultrastructure, leaf photosynthesis and seed yield of two soybean cultivars [Glycine max (L.) Merr. cv. Zhonghuang 13 and cv. Zhonghuang 35] at the Free-Air Carbon dioxide Enrichment (FACE) experimental facility in North China. Photosynthetic acclimation occurred in soybean plants exposed to long-term elevated [CO2] and varied with cultivars and developmental stages. Photosynthetic acclimation occurred at the beginning bloom (R1) stage for both cultivars, but at the beginning seed (R5) stage only for Zhonghuang 13. No photosynthetic acclimation occurred at the beginning pod (R3) stage for either cultivar. Elevated [CO2] increased the number and size of starch grains in chloroplasts of the two cultivars. Soybean leaf senescence was accelerated under elevated [CO2], determined by unclear chloroplast membrane and blurred grana layer at the beginning bloom (R1) stage. The different photosynthesis response to elevated [CO2] between cultivars at the beginning seed (R5) contributed to the yield difference under elevated [CO2]. Elevated [CO2] significantly increased the yield of Zhonghuang 35 by 26% with the increased pod number of 31%, but not for Zhonghuang 13 without changes of pod number. We conclude that the occurrence of photosynthetic acclimation at the beginning seed (R5) stage for Zhonghuang 13 restricted the development of extra C sink under elevated [CO2], thereby limiting the response to elevated [CO2] for the seed yield of this cultivar., X. Y. Hao ... [et al.]., and Obsahuje bibliografii
In this study, we chose apple leaf as plant material and studied effects of GeO2 on operation of photosynthetic apparatus and antioxidant enzyme activities under strong light. When exogenous GeO2 concentration was below 5.0 mg L-1, maximum photochemical quantum yield of PSII and actual quantum yield of PSII photochemistry increased significantly compared with the control under irradiances of 800 and 1,600 μmol(photon) m-2 s-1. Photosynthetic electron transport chain capacity between QA-QB, QA-PSI acceptor, and QB-PSI acceptor showed a trend of rising up with 1.0, 2.0, and 5.0 mg(GeO2) L-1 and declining with 10.0 mg(GeO2) L-1. On the other hand, dissipated energy via both ΔpH and xanthophyll cycle decreased remarkably compared with the control when GeO2 concentration was below 5.0 mg L-1. Our results suggested that low concentrations of GeO2 could alleviate photoinhibition and 5.0 mg(GeO2) L-1 was the most effective. In addition, we found, owing to exogenous GeO2 treatment, that the main form of this element in apple leaves was organic germanium, which means chemical conversion of germanium happened. The organic germanium might be helpful to allay photoinhibition due to its function of scavenging free radicals and lowering accumulation of reactive oxygen species, which was proven by higher antioxidant enzyme activities., Z. B. Wang, Y. F. Wang, J. J. Zhao, L. Ma, Y. J. Wang, X. Zhang, Y. T. Nie, Y. P. Guo, L. X. Mei, Z. Y. Zhao., and Obsahuje bibliografii
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 activity measured with fluorescence techniques. These findings lend partial support for a previously hypothesized function of guttation: prevention of excess water in leaves, yet they contradict those of several other studies. More work is required in order to adequately understand the function of guttation., Y.-C. Chen, T.-C. Lin, C. E. Martin., and Obsahuje bibliografii
The Tisza River Basin is an important area as it is a green corridor in which there are highly endangered habitats and a high level of biodiversity. The patterns in the species richness of invertebrates and the environmental conditions affecting these patterns are poorly studied in the grassy habitats in the lower reaches of the Tisza River Basin. The present study focuses on the effects of flooding, habitat and landscape features on the species richness of orthopterans at 24 grassland sites in two different landscapes. The relations between the explanatory variables and the pattern of diversity of orthopterans with different life-history traits were studied, using ordination and Generalized Linear Mixed Models. Although the influential factors for the different trait groups differed, we suggest that landscape features are the most important in shaping orthopteran assemblages, whereas habitat characteristics and flooding have comparatively little effect. Habitat characteristics affected only the non-xerophilous and Ensifera species and only the species richness of non-xerophilous orthopterans in flooded and non-flooded sites differed. We emphasize that even in countries where there are still considerable areas of high value natural grasslands, such as Hungary, non-protected meadows, linear grassy habitats (dikes, ditch banks, road verges, etc.) need more attention and should be given higher priority in the conservation of invertebrates., Attila Torma, Miklós Bozsó., and Obsahuje bibliografii
Water is a limited resource and is likely to become even more restricted with climate change. The aim of this study was to evaluate the effect of humic acid (HA) applications on photosynthesis efficiency of rapeseed plants under different watering conditions. Water stress strongly increased electron transport flux, probability that trapped excitation can move an electron into the electron transport chain beyond QA, and quantum yield of reduction of end electron acceptors at the PSI acceptor side. Application of HA decreased the values of these parameters to be similar to those of non-stress conditions. We found that, the application of HA improved plants net photosynthesis under water stress via increasing the rate of gas exchange and electron transport flux in plants., R. Lotfi, H. M. Kalaji, G. R. Valizadeh, E. Khalilvand Behrozyar, A. Hemati, P. Gharavi-Kochebagh, A. Ghassemi., and Obsahuje bibliografii
Photoprotection mechanisms protect photosynthetic organisms, especially under stress conditions, against photodamage that may inhibit photosynthesis. We investigated the effects of short-term immersion in hypo- and hypersalinity sea water on the photosynthesis and xanthophyll cycle in Sargassum fusiforme (Harvey) Setchell. The results indicated that under moderate light [110 μmol(photon) m-2 s-1], the effective quantum yield of PSII was not reduced in S. fusiforme fronds after 1 h in hyposalinity conditions, even in fresh water, but it was significantly affected by extreme hypersalinity treatment (90‰ sea water). Under high light [HL, 800 μmol(photon) m-2 s-1], photoprotective mechanisms operated efficiently in fronds immersed in fresh water as indicated by high reversible nonphotochemical quenching of chlorophyll fluorescence (NPQ) and de-epoxidation state; the quantum yield of PSII recovered during the subsequent relaxation period. In contrast, fronds immersed in 90‰ sea water did not withstand HL, barely developed reversible NPQ, and accumulated little antheraxanthin and zeaxanthin during HL, while recovery of the quantum yield of PSII was severely inhibited during the subsequent relaxation period. The data provided concrete evidence supporting the
short-term tolerance of S. fusiforme to immersion in fresh water compared to hypersalinity conditions. The potential practical implications of these results were also discussed., X. J. Xie, X. L. Wang, L. D. Lin, L. W. He, W. H. Gu, S. Gao, X. F. Yan, G. H. Pan, M. J. Wu, G. C. Wang., and Obsahuje seznam literatury
L-malate, a tricarboxylic acid cycle (TCA ) intermediate, plays an important role in transporting NADH from cytosol to mitochondria for energy production and may be involved in the beneficial effects of improving physical stamina. In the present study, we investigated the effects of L-malate on the performance of forced swimming time and blood biochemical parameters related to fatigue – blood urea nitrogen (BUN), glucose (Glc), creatine kinase (CK) , total protein (TP) and lactic acid (LA). To investigate the effects of L-malate on the malate-aspartate shuttle and energy metabolism in mice, the activities of enzymes related to the malate-aspartate shuttle were measured. L-malate was orally administered to mice continuously for 30 days using a feeding atraumatic needle. The swimming time was increased by 26.1 % and 28.5 %, respectively, in the 0.210 g/kg and 0.630 g/kg L-malate-treated group compared with the control group. There were no differences in the concentrations of Glc, BUN and TP between the L-malate-treated groups and the control groups. However, the levels of CK were significantly decreased in the L-malate-treated groups. The results predict a potential benefit of L-malate for improving physical stamina and minimizing muscle damage during swimming exercise. The activities of cytosolic and mitochondrial malate dehydrogenase were significantly elevated in the L-malate-treated group compared with the control group. These enzymatic activities may be useful indicators for evaluating changes affecting the malate-aspartate shuttle and energy metabolism in the liver of mice., J. L. Wu, Q. P. Wu, J. M. Huang, R. Chen, M. Cai, J. B. Tan., and Obsahuje bibliografii a bibliografické odkazy