256 research outputs found

    Intraspecific variation in sensitivity to ultraviolet-B radiation in endogenous hormones and photosynthetic characteristics of 10 wheat cultivars grown under field conditions

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    AbstractField studies were conducted to determine the potential of altering endogenous hormones and photosynthetic characteristics and intraspecific variation in sensitivity of 10 wheat (Triticum aestivum) cultivars (four tolerant, two middle sensitive and four sensitive) to enhanced ultraviolet-B (UV-B, 280–315nm) radiation under field conditions. The supplemental UV-B radiation was 5.00kJm−2, simulating a depletion of 20% stratospheric ozone. Responses were cultivar-specific. Out of the 10 tested wheat cultivars, six showed significant decrease in IAA content. UV-B radiation significantly increased ZR content in two wheat cultivars and significantly decreased in five cultivars. ABA content of three wheat cultivars was increased significantly, while that of five cultivars was decreased significantly. UV-B radiation significantly increased the stomatal conductance of three cultivars, and significantly decreased that of four cultivars. Intercellular CO2 concentrations were significantly increased in five cultivars and significantly decreased in one cultivar (Mianyang 20). Transpiration rate of three cultivars significantly increased, while that of three cultivars significantly decreased. UV-B radiation significantly decreased the net photosynthetic rate of six cultivars. Intraspecific differences were found for the different measured parameters. For seven measured parameters, UV-B radiation had significant effects on five wheat cultivars, while no effect on the others. Significant correlations were observed between net photosynthetic rate and stomatal conductance, intercellular CO2 concentrations and transpiration rate in eight cultivars. UV-B radiation might change stomatal conductance, intercellular CO2 concentrations and transpiration rate, thus resulting in changes in net photosynthetic rate

    Alkaloid content and essential oil composition of Mahonia breviracema cultivated under different light environments

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    Light can affect the yields of alkaloid and essential oil in the synthesis of secondary metabolites directly or indirectly through plant growth. Despite Mahonia breviracema being an endemic medicinal species in China, research on the influence of light on production of alkaloid and essential oil is scarce. Thus, this research evaluated the influence of various lighting conditions on alkaloid yields and the composition and yields of the essential oils of M. breviracema. The results revealed significant differences in alkaloid yields, oil yieldsand chemical characteristics of M. breviracema grown in four different light intensities from 10 to 100% full sun shine. The total amount of alkaloids in plants under I30 and I50 was higher than that under I10 and I100 due to the higher biomass of plants. Oil yield of M. breviracema leaf increased linearly with the increase of lightincidence. Plants grown under I10 had less plastoglobuli, which coincided with the lowest oil yield (1.91 g kg-1). The plastoglobuli in chloroplasts increased when the irradiance levels increased, resulting in the highest oil yields under I100 (4.53 g kg-1). The principal components in the leaves of M. breviracema were hexadecanoic acid (10.54-72.19%) and α-ionone (1.25-42.39%). The highest hexadecanoic acid content was obtained under I50, followed by I30, and the highest α-ionone content was obtained under I100. Therefore, it is necessary to control the light environment to obtain raw materials with high quality

    Premixed jet flame characteristics of syngas using OH planar laser induced fluorescence

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    Lean premixed flame characteristics of several typical low calorific value (LCV) syngases (basis CO/H-2/CH4/CO2/N-2), including bituminous coal, wood residue, corn core, and wheat straw gasification syngas, were investigated using OH planar laser induced fluorescence (PLIF) technology. OH radical distributions within the turbulent flame were measured for different turbulence intensities. Flame structures of syngases were analyzed and characterized with respect to burnt and unburnt regions, flame curvature (sharp cusp), local extinction (holes and penetration), OH reaction layer thickness, wrinkling, and other features, with OH-PLIF instantaneous images and statistical analysis. Results show that H-2 content, LCV, and turbulence intensity are the most effective factors influencing the OH radical intensity and thickness of OH radical layers. The bituminous coal gasification syngas with relatively higher LCV and H-2 content tends to burn out easily. Through changes in thickness of the OH radical layers and signal intensities, the reaction layer can be compressed by intensifying turbulence and thereby the combustion processes of syngas

    Responses of nitrogen utilization and apparent nitrogen loss to different control measures in the wheat and maize rotation sytsem

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    Nitrogen (N) is an essential macronutrient for plant growth and excessive application rates can decrease crop yield and increase N loss into the environment. Field experiments were carried out to understand the effects of N fertilizers on N utilization, crop yield and net income in wheat and maize rotation system of the North China Plain (NCP). Compared to farmers’ N rate (FN), the yield of wheat and maize in reduction N rate by 21–24% based on FN (RN) was improved by 451 kg ha-1, N uptakes improved by 17 kg ha-1 and net income increased by 1671 CNY ha-1, while apparent N loss was reduced by 156 kg ha-1. The controlled-release fertilizer with a 20% reduction of RN (CRF80%), a 20% reduction of RN together with dicyandiamide (RN80%+DCD) and a 20% reduction of RN added with nano-carbon (RN80%+NC) all resulted in an improvement in crop yield and decreased the apparent N losses compared to RN. Contrasted with RN80%+NC, the total crop yield in RN80%+DCD improved by 1185 kg ha-1, N uptake enhanced by 9 kg ha-1 and net income increased by 3929 CNY ha-1, while apparent N loss was similar. Therefore, a 37–39% overall decrease in N rate compared to farmers plus the nitrification inhibitor, DCD, was effective N control measure that increased crop yields, enhanced N efficiencies, and improved economic benefits, while mitigating apparent N loss. There is considerable scope for improved N use effieincy in the intensive wheat -maize rotation of the NCP

    Gypenosides alleviate cone cell death in a zebrafish model of retinitis pigmentosa

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    Retinitis pigmentosa (RP) is a group of visual disorders caused by mutations in over 70 genes. RP is characterized by initial degeneration of rod cells and late cone cell death, regardless of genetic abnormality. Rod cells are the main consumers of oxygen in the retina, and after the death of rod cells, the cone cells have to endure high levels of oxygen, which in turn leads to oxidative damage and cone degeneration. Gypenosides (Gyp) are major dammarane-type saponins of Gynostemma pentaphyllum that are known to reduce oxidative stress and inflammation. In this project we assessed the protective effect of Gyp against cone cell death in the rpgrip1 mutant zebrafish, which recapitulate the classical pathological features found in RP patients. Rpgrip1 mutant zebrafish were treated with Gyp (50 ”g/g body weight) from two-months post fertilization (mpf) until 6 mpf. Gyp treatment resulted in a significant decrease in cone cell death compared to that of untreated mutant zebrafish. A markedly low level of reactive oxygen species and increased expression of antioxidant genes were detected in Gyp-incubated mutant zebrafish eyes compared to that of untreated mutant zebrafish. Similarly, the activities of catalase and superoxide dismutase and the level of glutathione were significantly increased in Gyp-treated mutant zebrafish eyes compared to that of untreated mutant zebrafish. Gyp treatment also decreased endoplasmic reticulum stress in rpgrip1 mutant eyes. Expression of proinflammatory cytokines was also significantly decreased in Gyp-treated mutant zebrafish eyes compared to that of untreated mutant zebrafish. Network pharmacology analysis demonstrated that the promotion of cone cell survival by Gyp is possibly mediated by multiple hub genes and associated signalling pathways. These data suggest treatment with Gyp will benefit RP patients

    Correlation analysis of chlorogenic acid and luteoloside biosyntheses with transcription levels of HQTs and FNSs in Lonicera species

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    Organic acids and flavonoids are the main active components in Lonicera species. Chlorogenic acid and luteoloside are important components, and their synthesis is regulated in plants by the phenyl-propanoid synthesis pathway. Downstream of the phenylpropanoid synthesis pathway, hydroxycinnamoyl CoA quinate hydroxycinnamoyl transferase (HQT) and flavone synthase (FNS) are critical enzymes that are involved in chlorogenic acid and luteoloside biosynthesis, respectively.In this study, we first determined the dynamic accumulations of chlorogenic acid, luteoloside and other active components in different growth stages of the flower buds of Lonicera fulvotomentosa through HPLC-DAD and then investigated the expressions of the LJHQT and LJFNS gene families by q-RT-PCR. In addition, we also compared the expression levels of HQT and FNS orthologous genes in vari-ous tissues of Lonicera japonica, L. fulvotomentosa, and Lonicera hypoglauca.The results indicated that the chlorogenic acid contents exhibit leaf accumulation that is preferential in L. fulvotomentosa but exhibit bud accumulation that is preferential in L. japonica and L. hypoglauca. The luteoloside contents show preferential leaf accumulation in these three species. Our results suggest that the leaves and buds of these three species are rich in medicinal ingredients, including chlorogenic acid (CGA) and luteoloside, and therefore can be used as a material to extract CGA and luteoloside rather than being wasted. Furthermore, combined with the transcript expression levels of HQTs and FNSs, we explained the species-specific and tissue-specific occurrence of CGA and luteoloside. We analyzed dynamic changes of components and gene expression and demonstrated that the expressions of HQTs and FNSs in these three species are closely related to the synthesis of chlorogenic acid and luteoloside

    Controlling coherence using the internal structure of hard pi pulses

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    The tiny difference between hard pi pulses and their delta-function approximation can be exploited to control coherence. Variants on the magic echo that work despite a large spread in resonance offsets are demonstrated using the zeroth- and first-order average Hamiltonian terms, for 13-C NMR in C60. The 29-Si NMR linewidth of Silicon has been reduced by a factor of about 70,000 using this approach, which also has potential applications in magnetic resonance microscopy and imaging of solids.Comment: 4 pages, 4 color figure

    Forest diversity and community dynamics along an altitudinal gradient of Ailaoshan Mountain (Yuanyang, Yunnan Province, China)

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    In order to evaluate forest community diversity, the quantity of forest community succession along an altitudinal gradient from 1690 to 2016 m above sea level, the understanding of relationships between diversity and community dynamics, and data from sampling plots of forest communities were studied. Forest communities were mid-mountain moist evergreen broad-leaved forests on the southern slope of the Ailaoshan Mountain in Yuanyang County (near the Hani terraces) in Yunnan Province, China. The results showed that (1) the mean species richness, ecological dominance, and evenness (E) were 9.16, 0.31, and 0.27, respectively. The mean Shannon-Wiener Index and Coverage Weighted Foliage-Height Diversity Index were 0.84 and 0.41, respectively. (2) The mean live aboveground biomass (AGS) was 99.23 Mg/ha and the mean Composition Index (CI) was 182.17. Species diversity (including E, richness, and Shannon-Wiener Index), live AGS, and CI could be predicted by the mid-domain effect (MDE), which displayed a unimodal pattern against elevation. (3) Richness, E, Shannon-Wiener Index, and Coverage Weighted Foliage-Height Diversity Index increased with CI. Ecological dominance decreased with increased CI, following a quadratic relationship. Whittaker Index decreased with both increased CI and AGS, with a quadratic relationship. Much forest diversity could be explained by the MDE. However, forest dynamics were seriously disturbed by human activities. More attention should focus on increasing forest diversity in order to prevent the degradation of forest ecological functions thus resulting in threats to the sustainable development of the local ecological systems

    Root morphological, Cd accumulation and tolerance characteristics of 2 Dianthus caryophyllus cultivars under Cd stress

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    For studying the physiological response of two different Dianthus caryophyllus cultivars on Cd stress, pot experiment was carried out to measure proline and glutathione in leaves, five types of organic acids in root exudates (oxalic acid, malic acid, acetic acid, tartaric acid, citric acid), soluble sugars and free amino acids, root length, root surface area, root volume, root projected area and Cadmium content in soil, plant roots and aboveground. According to the effects of cadmium stress on the physiological and biochemical characteristics of two Dianthus caryophyllus, the results showed that: the growth of two cultivars are affected, “Master” and “Xiao Yan” are manifested as plant height, leaf, flower buds and biomass decreased, but the “Master” by the stronger inhibitory effect. The root length, total root surface area, total root projected area, and average root diameter of the “Master” increased under cadmium stress, but the root volume decreased. However, the root length, total root surface area, root volume, and root projected area of the “Xiao Yan” under cadmium stress decreased, while the average root diameter increased. The glutathione in the leaves of the two cultivars decreased, the proline content of the leaves of the “Xiao Yan” increased, while that of the “Master” decreased. In the root exudates, the free amino acid content of the two cultivars are reduced, and the secretion of organic acids is also inhibited (except for the citric acid secreted in the “Master”), while the soluble sugar content in the root exudates is expressed as “Xiao Yan” increased, and the “Master” decreased. According to the physiological response to the two cultivars under cadmium stress, the “Xiao Yan” is more suitable for soil restoration in the mining area of Lanping area

    Protection of p-coumaric acid against chronic stress-induced neurobehavioral deficits in mice via activating the PKA-CREB-BDNF pathway

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    There is a body of evidence to suggest that chronic stress modulates neurochemical homeostasis, alters neuronal structure, inhibits neurogenesis and contributes to development of mental disorders. Chronic stress-associated mental disorders present common symptoms of cognitive impairment and depression with complex disease mechanisms. P-coumaric acid (p-CA), a natural phenolic compound, is widely distributed in vegetables, cereals and fruits. P-CA exhibits a wide range of health-related effects, including anti-oxidative-stress, anti-mutagenesis, anti-inflammation and anti-cancer activities. The current study aims to evaluate the therapeutic potential of p-CA against stress-associated mental disorders. We assessed the effect of p-CA on cognitive deficits and depression-like behavior in mice exposed to chronic restraint stress (CRS); we used network pharmacology, biochemical and molecular biological approaches to elucidate the underlying molecular mechanisms. CRS exposure caused memory impairments and depression-like behavior in mice; p-CA administration attenuated these CRS-induced memory deficits and depression-like behavior. Network pharmacology analysis demonstrated that p-CA was possibly involved in multiple targets and a variety of signaling pathways. Among them, the protein kinase A (PKA) - cAMP-response element binding protein (CREB) - brain derived neurotrophic factor (BDNF) signaling pathway was predominant and further characterized. The levels of PKA, phosphorylated CREB (pCREB) and BDNF were significantly lowered in the hippocampus of CRS mice, suggesting disruption of the PKA-CREB-BDNF signaling pathway signaling pathway; p-CA treatment restored the signaling pathway. Furthermore, CRS upregulated expression of proinflammatory cytokines in hippocampus, while p-CA reversed the CRS-induced effects. Our findings suggest that p-CA will offer therapeutic benefit to patients with stress-associated mental disorders
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