Both the photosynthetic light curves and CO(2) curves of Juglans regia L. and Ziziphus jujuba Mill. var. spinosa in three seasons were measured using a LI-6400 portable photosynthesis system. The maximal net photosynthetic rate (A(max)), apparent quantum efficiency(phi), maximal carboxylation rate (V(cmax)) and water use efficiency (WUE) of the two species were calculated based on the curves. The results showed that A(max) of J. regia reached its maximum at the late-season, while the highest values of A(max) of Z. jujuba occurred at the mid-season. The A(max) of J. regia was more affected by relative humidity (RH) of the atmosphere, while that of Z. jujuba was more affected by the air temperature. Light saturation point (LSP) and Light compensation point (LCP) of J. regia had a higher correlation with RH of the atmosphere, those of Z. jujuba, however, had a higher correlation with air temperature. V(cmax) of both J. regia and Z. jujuba had negative correlation with RH of the atmosphere. WUE of J. regia would decrease with the rise of the air temperature while that of Z. jujuba increased. Thus it could be seen that RH, temperature and soil moisture had main effect on photosynthesis and WUE of J. regia and Z. jujuba. Incorporating data on the physiological differences among tree species into forest carbon models will greatly improve our ability to predict alterations to the forest carbon budgets under various environmental scenarios such as global climate change, or with differing species composition.
Secondary metabolites are considered to be the major compounds in Cordyceps with anti-tumor, anti-aging and immunity-enhancing effects. The molecular structures of secondary metabolites form the basis for the development and utilization of Cordyceps. Metacordyceps neogunnii is an important Cordyceps resource, but less study has been made on the molecular structure of its secondary metabolites. In this study, gas chromatography-mass spectrometry (GC/MS) and ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) were used to analyze and identify the secondary metabolites from CH3OH/H2O extract of Metacordyceps neogunnii. The results show that a total of 22 compounds were identified by GC-MS, including 2 n-alkanes, 1 isoparaffin, 1 cycloalkane, 6 olefins and 13 esters. The predominant compounds were (E)-ocimene, (E)-β-ocimene, methyl oleate, dioctyl adipate, methyl palmitate and methyl linoleate, obtained by means of GC/MS. Five distince classes of secondary metabolites were speculated: 3 polypeptides, 2 esters, 1 isoflavone, 1 isoindrone and 3 amides, from which 10 compounds were detected using UPLC-Q-TOF/MS. (R)-N-((1-(((9H-fluorene-9-yl) methoxy) carbonyl) pyrrolidine-2-yl) methyl)-N-(2-(6-benzoylamino-9H-purin-9-yl) acetyl) glycine, benzyl (5-(2-((3-(2, 3-dihydrobenzo[b] [1, 4] dioxin-6-yl)-4-carbonyl-4H-chromene-7-yl) oxo) acetylamino) amyl) carbamate, 5, 5’-((propane-2, 2-diyl (4, 1-phenylene)) bis (oxo)) bis (2-(naphthalene-1-yl) isoindoline-1, 3-dione), 1-dodecylazepine-2-one and other compounds were the first detected in Metacordyceps neogunnii.
Heavy metals mainly enter tea from the soil. In this study, stratified soil samples were collected, at a depth of 0–60 cm, using a soil drill in An-tea plantations. Speciation of As, Cd, Cr, Cu, Ni, Pb, and Zn was determined using the European Community Bureau of Reference sequential extraction method, and the heavy metal concentrations in the extracts were determined by inductively coupled plasma−mass spectrometry. Compared with other soil layers, the mean Cd, Cu, Pb, and Zn concentrations were highest in the 0–20 cm layer, the Ni concentrations were highest in the 20–40 cm layer, and the As and Cr concentrations were highest in the 40–60 cm layer. The mean contributions of the non-residual fractions, including the acid-soluble, reducible, and oxidizable fractions, to the total concentrations were higher than those of the residual fraction for Cr, Cu, and Ni at all depths in soil from a flat area, as well as for Cd and Zn at all depths in soil from a sloping area. The contributions of non-residual fractions to the total As and Pb concentrations were higher than those of the residual fraction in soil from a depth of 0–20 cm from the flat area and soil from a depth of 20–60 cm from the sloping area. The total heavy metal concentrations correlated well with the acid-soluble fraction and reducible fraction concentrations in soil from 0–40 cm.
Renewable and economical generation of hydrogen via electrochemical methods shows great potential in addressing the energy crisis. In this study, an emerging molten salt method was adopted for the synthesis of a cerium-modified rhenium disulfide nanosheet for electrical hydrogen evolution reactions. The prepared 1% Ce-doped rhenium disulfide (ReS2) sample showed promoted hydrogen evolution performance in both acid and alkaline electrolytes compared to bare ReS2. Generating of abundant defects in ReS2 exposed more reaction active sites. Moreover, adding cerium accelerated the hydrogen evolution dynamics. Hopefully, this work will offer new insight into developing ReS2-based electrocatalysts for hydrogen evolution reactions.
To investigate the effects of different aging times, three An–tea samples were selected for comparison with a non-aged sample as the control (CK, one-year-old) and labeled as high-aged (HAS, 12 years old), medium-aged (MAS, 7 years old), and low-aged samples (LAS, 2 years old). Changes in the volatile components of the different An–tea samples were investigated using headspace–solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC-MS). The volatile components of An–tea consisted of eight types of compounds. Aldehydes and hydrocarbons were dominant in LAS, while esters, ketones, alcohols, nitrogen-containing compounds, and ethers were the most abundant compound in MAS. Esters were dominant in HAS, while phenols were only present in LAS and CK. As aging time increased, the number of identical compounds gradually decreased, while the relative contents of the alcohols also decreased. Except for CK, the contents of ketones and aldehydes gradually decreased as the aging time increased. The content of aldehydes greatly increased during the initial aging period. Ketones and esters had markedly increased in HAS, while their abundance in LAS was close to that in CK. The comprehensive quality score of the volatile components obtained by principal component analysis was highest for MAS, followed by HAS and LAS, with CK having the lowest score.
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