This study investigated whether gas exchange and the present content of antioxidant compounds can contribute to the survival of Euterpe oleracea plants in environments of frequent waterlogging. A factorial randomised, experimental design included two distinct water conditions (waterlogging and control) and five evaluation times (0, 6, 12, 18, and 24 d). Gasexchange parameters, leaf temperature, electrolyte leakage, and contents of antioxidant compounds were measured. Waterlogging did not promote significant alterations in net photosynthetic rate and transpiration, and stomatal conductance was reduced only after 18 d. Malondialdehyde and glutathione contents did not significantly change during waterlogging. Additionally, electrolyte leakage was significant only after 18 d of waterlogging. Thus, this study revealed that maintenance in gas exchange and antioxidant compounds might contribute to the survival of E. oleracea plants in environments exposed to waterlogging., T. S. Pereira, A. K. S. Lobato, G.A.R. Alves, R.N. Ferreira, O.N. Silva, A. P. Martins Filho, E.S. Pereira, L.S. Sampaio., and Obsahuje bibliografii
Intercropping is a sustainable agricultural practice used worldwide for highly efficient utilization of resources. However, short crops often grow under the shade of the canopy of tall crops in intercropping systems. Plants evolved two main strategies to deal with shade: avoidance and tolerance. Soybean (Glycine max), a legume crop, is often planted in intercropping. But little is known about a strategy that soybean may employ to deal with shade at seedling stage. Therefore, we determined morphological and physiological traits related to shade tolerance and shade avoidance in seedlings of two varieties. Generally, both varieties showed similar shade tolerance traits, such as increased specific leaf area and chlorophyll (Chl) content, and reduced photosynthetic capacity and the Chl a/b ratio. The light-limiting environment eliminated the benefits of shade tolerance traits for the carbon gain, which led to similar real-time photosynthesis and biomass in intercropping. By contrast, two varieties expressed different changes in shade avoidance traits. The variety Guixia 3 exhibited clear preference of shade avoidance that resulted in a high main stem, hypocotyl elongation, and biomass allocation towards the stem. The variety Gongxuan 1 showed those traits less. We suggested that the genetic variation occurs within soybean, thus the shade avoidance related traits might be important for variety selection for intercropping. Hence, the evaluation of performance should focus on shade avoidance in soybean genotypes in future experiments., W. Z. Gong, C. D. Jiang, Y. S. Wu, H. H. Chen, W. Y. Liu, W. Y. Yang., and Obsahuje bibliografii
Due to emerging high spectral resolution, remote sensing techniques and ongoing developments to retrieve the spectrally resolved vegetation fluorescence spectrum from several scales, the light reactions of photosynthesis are receiving a boost of attention for the monitoring of the Earth's carbon balance. Sensor-retrieved vegetation fluorescence (from leaf, tower, airborne or satellite scale) originating from the excited antenna chlorophyll a molecule has become a new quantitative biophysical vegetation parameter retrievable from space using global imaging techniques. However, to retrieve the actual quantum efficiencies, and hence a true photosynthetic status of the observed vegetation, all signal distortions must be accounted for, and a high-precision true vegetation reflectance must be resolved. ESA's upcoming Fluorescence Explorer aims to deliver such novel products thanks to technological and instrumental advances, and by sophisticated approaches that will enable a deeper understanding of the mechanics of energy transfer underlying the photosynthetic process in plant canopies and ecosystems., S. Van Wittenberghe, N. Sabater, M. P. Cendrero-Mateo, C. Tenjo, A. Moncholi, L. Alonso, J. Moreno., and Obsahuje bibliografické odkazy
Environmental pollution by antibiotics poses a potential ecological risk to aquatic photosynthetic organisms. In the present study, toxic effects of erythromycin on PSI and PSII were investigated in cyanobacteria culture medium of Microcystis aeruginosa. The activity and electron transport of both photosystems were affected by erythromycin in a concentrationdependent manner. The quantum yield of PSII (YII) was reduced at 0.1 mg L-1 of erythromycin, while the quantum yield of PSI (YI) significantly decreased at concentration of 5-25 mg L-1. The decline of YII was accompanied by an increase of nonregulated energy dissipation (YNO). At 10 mg L-1 of erythromycin, YII decreased by 55%, while YNO increased by 18%. The decrease of YI induced by erythromycin was caused by donor-side limitation of PSI (YND). YND was markedly enhanced with elevated erythromycin concentration. At 10 mg L-1 of erythromycin, YI and YNA (PSI acceptor-side limitation) decreased by 8 and 82%, respectively, while YND rose by 314%. The quantum yield of cyclic electron flow increased significantly at 0.1-1 mg L-1 of erythromycin; it decreased but remained higher than that of the control at 5-25 mg L-1 of erythromycin. The contribution of cyclic electron flow to YI, and to linear electron flow rose significantly with the increasing erythromycin concentration. The maximum values of electron transport rates in PSII and PSI decreased by 71 and 24.3%, respectively, at 25 mg L-1 of erythromycin. Compared with the untreated control, the light saturation of PSII and PSI decreased significantly with increasing erythromycin concentration. We showed that concentrations of erythromycin >- 5 mg L-1 could exert acute toxicity to cyanobacteria, whereas the chronic toxicity caused by concentrations of ng or μg L-1 needs further research., C.-N. Deng, D.-Y. Zhang, X.-L. Pan., and Obsahuje bibliografii
The aim of this study was to determine the impact of increased copper contents on selected physiological processes in oneyear-old Pinus sylvestris L. needles from a former German timber storage area in Warcino Forest District, a subject to an environmental quality survey. Samples were collected from the area with the high copper content in the soil. The control area was a nearby pine tree stand showing unimpeded growth. The significant growth inhibition was found in dwarf shoots and whole needles, increased water content, and reduced dry mass were also observed. The chlorophyll content was lowered, while 20% higher electrolyte leakage was found. Chlorophyll a fluorescence indicated only higher values of the nonphotochemical quenching in P. sylvestris from the Cu-site. Significant differences were shown in the rate of gas exchange measured by changes in carbon dioxide or oxygen concentration. The intensity of photosynthesis in needles of P. sylvestris from the Cu-site measured by CO2 uptake was considerably higher than that of oxygen production. The rate of respiration in the needles from the Cu-site measured by the amount of released CO2 was higher only by 15%, while according to O2 consumed, the rate increased by 30% in relation to the control. Our results suggest that the copper accumulation in P. sylvestris needles affected the morphology and physiology of the studied organs., K. Możdżeń, T. Wanic, G. Rut, T. Łaciak, A. Rzepka., and Obsahuje bibliografii
Seedling recruitment is a critical developmental stage in regeneration of plant populations under Mediterranean conditions that strongly depends on water availability. Seed mass and relative growth rate (RGR) may affect the early establishment of seedlings through different physiological processes. Here, we examined the effects of the seed mass and carbon balance on seedling growth under two water regimes in Rhamnus alaternus L. and Rhamnus ludovici-salvatoris, two Mediterranean shrubs, showing a different ability to recruit seedlings. Plant water consumption and biomass accumulation (ΔB) were measured during three periods of the growth in order to estimate water use efficiency (WUE), RGR, and its components. Additionally, net photosynthesis and leaf, stem, and root respiration were measured in plants grown in pots well watered and under progressive drought. Rhamnus alaternus showed the higher seed mass, ΔB, and plant WUE than that of R. ludovici-salvatoris in all periods and water regimes. The higher RGR of R. alaternus was observed during the first and the second period, but the reverse trend was registered during the third period as a consequence of the higher initial biomass of R. alaternus. Also, R. alaternus showed a higher specific leaf area and estimated carbon balance than that of R. ludovicisalvatoris. The observed differences in ΔB, estimated carbon balance, seed mass, and WUE between both species could explain their different distribution and ability to recruit seedlings under natural conditions., H. El Aou-Ouad, I. Florez-Sarasa, M. Ribas-Carbó, J. Flexas, H. Medrano, J. Gulías., and Obsahuje seznam literatury
High salt concentration is a major abiotic stress limiting plant growth and productivity in many areas of the world. Elaeagnus angustifolia L. adapts to adverse environments and is widely planted in the western region of China as a windbreaker and for landscape and soil stabilization. High salt concentrations inhibited photosynthesis of E. angustifolia, but the mechanism is not known. In this paper, RNA-sequencing was used to investigate effects of salt stress on the photosynthetic characteristics of the species. In total, 584 genes were identified and involved in photosynthetic pathways. The downregulation of genes that encode key enzymes involved in photosynthesis and genes correlated to important structures in photosystem and light-harvesting complexes might be the main reason, particularly, the downregulation of the gene that encodes magnesium chelatase. This would decrease the activity of enzymes involved in chlorophyll synthesis and the downregulation of the key gene that encodes Rubisco, and thereby decreases enzyme activity and the protein content of Rubisco., J. Lin, J. P. Li, F. Yuan, Z. Yang, B. S. Wang, M. Chen., and Obsahuje bibliografii
RNA gel hybridization showed that the expression of monodehydroascorbate reductase (MDHAR) in the wild type (WT) tomato was decreased firstly and then increased under salt- and polyethylene glycol (PEG)-induced osmotic stress, and the maximum level was observed after treatment for 12 h. WT, sense transgenic and antisense transgenic tomato plants were used to analyze the antioxidative ability to cope with osmotic stresses. After salt stress, the fresh mass (FM) and height of sense transgenic lines were greater than those of antisense lines and WT plants. Under salt and PEG treatments, sense transgenic plants showed a lower level of hydrogen peroxide (H2O2) and malondialdehyde (MDA), a higher net photosynthetic rate (PN), and the maximal photochemical efficiency of PSII (Fv/Fm) compared with WT and antisense transgenic plants. Moreover, sense lines maintained higher ascorbate peroxidase (APX) activity than WT and antisense plants under salt- and PEG-induced osmotic stress. These results indicate that chloroplastic MDHAR plays an important role in alleviating photoinhibition of PSII by elevating ascorbate (AsA) level under salt- and PEG-induced osmotic stress., F. Li ... [et al.]., and Obsahuje bibliografii
Interactions involving host plants (cowpea, groundnut, cotton, sunflower, greengram, blackgram) an insect herbivore, black legume aphid Aphis craccivora Koch (Hemiptera: Aphididae) and a predator, the zigzag beetle Cheilomenes sexmaculata (Fabricius) (Coleoptera: Coccinellidae) were investigated during 2014-2015. The preference of the aphid A. craccivora for host plants measured in terms of growth and multiplication was cowpea > groundnut > greengram > blackgram > sunflower > cotton (most preferred to least preferred). Cowpea was the most preferred host plant for growth and multiplication of A. craccivora. Aphid's oviposition period was longest, fecundity greatest; adult longevity longest (188.40 ± 28.87 h; 52.00 ± 10.92; 231.60 ± 40.41 h), and nymphal mortality was lowest (0%) when reared on cowpea followed by groundnut, greengram and blackgram. Aphids had highest nymphal mortality (100%), with very few or no live adults produced, when reared on sunflower and cotton, the least preferred host of A. craccivora in this study. At the third trophic level, both the larvae and the adults of the coccinellid, Cheilomenes sexmaculata, consumed more of the aphids reared on groundnut than of those reared on blackgram, greengram, cowpea, sunflower and cotton. The biochemical constituents (phenols) present in cotton and sunflower, which contributed to the aphid's nymphal mortality, also affected the feeding behaviour of the coccinellid., Snehasish Routray, Karnam V. Hari Prasad., and Obsahuje bibliografii