Search

Alpine treelines are thought to be controlled by low temperature, which affects tree physiology and limits growth. Irrespective of carbon and nutrient limitations are physiological mechanisms affecting the formation of alpine treelines still needs to be defined. We measured the rates of tree growth (basal area increment, BAI), nutrient concentrations in leaves and roots, foliar concentration of nonstructural carbohydrates (NSCs), and gas exchange in Pinus taiwanensis at five elevations (1200, 1400, 1600, 1800, and 2000 m) in the Wuyi Mountains, China. Leaves and roots were sampled twice (summer and winter). The soil nitrogen (N) and phosphorus (P) concentrations and BAI were measured during the summer. We analyzed the foliar traits in summer and winter. The N:P ratio was also analyzed. BAI decreased significantly as elevation increased, accompanied by increases in foliar NSC, N, and P concentrations in both summer and winter. The root P concentration increased with elevation in summer, but the foliar N:P ratio and root N and P concentrations were not affected by elevation in winter. Foliar photosynthesis and respiration did not change in winter, but increased in summer as elevation increased. These results suggest that C and nutrients may not be limiting resources in P. taiwanensis at this alpine treeline site, which instead may be controlled by temperature. P. taiwanensis at alpine treelines accumulates C and nutrient to increase its rates of biochemical reactions at low temperatures.

Purpose In this study, NK4-conjugated hydroxycamptothecin liposomes (NK4-HCPT-Lips) were prepared with the aim of improving drug targeting to the liver. Methods NK4-HCPT-Lips were prepared using the thin-film dispersion method. In vitro antitumor activities were evaluated by MTT assay. HCPT levels in plasma and tissues were determined via high-performance liquid chromatography (HPLC) with camptothecin as the internal standard, and the characteristics, pharmacokinetics, and bio-distribution of NK4-HCPT-Lips were evaluated. Results The liposomes showed a regular spherical-shaped morphology, and the entrapment efficiency and drug loading capacity reached 82.5 ± 2.4% and 3.01 ± 0.23%, respectively, with a particle size of 155.6 ± 2.6 nm and a zeta potential of -24.8 ± 3.3 mV. Inhibition effect experiments found that NK4-HCPT-Lips had a good inhibition on the HepG2 cells. Pharmacokinetic studies revealed an increase in the area under the curve and mean residence time as well as a decrease in plasma clearance (p < 0.05) of the NK4-HCPT-Lips compared to those of HCPT liposomes and a commercial HCPT injection. Tissue distribution studies showed that NK4-HCPT-Lips were present at high levels in the liver but were cleared from the kidneys. Conclusion These results demonstrate that NK4-HCPT-Lips possess excellent liver-targeting attributes, which could enhance the therapeutic effects of drug treatments for hepatic diseases.

Acute lung injury represents a widespread, variable type of lung injury characterized by a low oxygen level in the blood, non cardiogenic pulmonary edema, low lung compliance and extensive capillary leakage. In our study, the Wistar rat mode of ALI was established using lipopolysaccharide (LPS). The rats were randomly divided into normal control (NC) group (n = 12) and miR-16 overex-pression group (n = 12), and they were transfected with empty vector and miR-16 overexpression virus, respectively. The lung tissues were extracted in both groups, and then the expression levels of miR-16 and NF-κB were detected via fluorescence quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and the association between their expressions was analyzed via Pearson correlation analysis. Moreover, the morphological changes in lung tissues were detected via hematoxylin-eosin (HE) staining, and the differences in the wet/dry weight (W/D) ratio and the pathomorphological score of lung tissues were compared between the two groups. The expression level of NF-κB was detected via immunohistochemistry (IHC) and Western blotting. Our results showed that, there were different degrees of lung injury in lung tissues in both groups. In miR-16 overexpression group, the W/D ratio was significantly higher than that in NC group (P < 0.05), and the pathomorphological score was also significantly higher than that in NC group (P < 0.05). The results of RT-PCR revealed that the mRNA levels of miR-16 and NF-κB in miR-16 overexpression group were 2.5 and 3.7 times higher than those in NC group. The results of Western blotting and IHC also showed that the activity of NF-κB in lung tissues was evidently enhanced in miR-16 overexpression group compared with that in NC group. According to the Pearson correlation analysis, there was a significant positive correlation between the mRNA levels of miR-16 and NF-κB in lung tissues (r = 0.705, P = 0.012). In conclusion, miR-16 activates the NF-κB pathway to initiate a series of inflammatory responses, thereby contributing to the occurrence of ALI in rats.

The carbon sequestration capacity of the forest ecosystem normally increases overage due to the carbon dynamic in below canopy and soil. The carbon dynamic is reflective of the forest characteristics and their interactions with climate, topographic, and soil conditions. In this study, we measured the carbon content and carbon density of canopy, shrub, understory vegetation, litter, and soil, and assessed carbon dynamics in three forest ecosystems (Cunninghamia lanceolate, Pinus massoniana, and Evergreen broad-leaved forests) with a combination of data from Fujian Provincial forest resource inventory. This study showed that the carbon content of the canopy layers increased over time, and the carbon content of the topsoil (0-30 cm) in the young forests was significantly higher than that in other age groups in Cunninghamia lanceolata forest and Pinus massoniana forest. Due to the carbon differences in the soil layer, the carbon stocks of the C. lanceolata forest and the P. massoniana forest declined from 1996 to 2007, but the carbon stocks of Evergreen broad-leaved forest increased. Besides, using the traditional carbon content coefficient (0.5) might underestimate the carbon sequestration potential of these forest ecosystems, especially for the mature forests. The coniferous forests displayed a short-term reduction in the carbon stocks of ecosystems between 10 and 20 years after afforestation, and the decline cannot be ignored in the carbon budget.

The conventional CO electrochemical gas sensor uses aqueous H2SO4 solution as electrolyte, with inevitable problems, such as the drying and leakage of electrolyte. Thus, research on new alternative electrolytes is an attractive field in electrochemical gas sensors. In this paper, the application of a new fumed SiO2 gel electrolyte was studied in electrochemical gas sensors. The effects of fumed SiO2 and H2SO4 contents on the performance of the CO gas sensor were investigated. The results showed that the optimized composition of the SiO2 gel electrolyte was 4.8% SiO2, 38% H2SO4, and 0.005% polyvinyl alcohol (PVA). Compared with aqueous H2SO4, the gel electrolyte had better water retention ability. The signal current of the sensor was proportional to the CO concentration. The sensitivity to CO was 78.6 nA/ppm, and the response and recovery times were 31 and 38 s, respectively. The detection limit was 2 ppm. The linear range was from 2 to 500 ppm. The gel electrolyte CO sensor possesses equivalent performance to that with aqueous electrolyte.

Leaves and roots are important resource acquisition organs of seedlings and both are sensitive to the environment. However, it is currently unclear whether leaf and root traits have a similar response model to nitrogen (N) deposition. Furthermore, the relationships between the responses of leaf and root traits to N deposition are still unknown.Exogenous nitrogen input experiments were conducted to simulate the effects of nitrogen deposition in Shunchang County, south of China. We measured the biomass, morphological characteristics, and nutrient concentrations (total of 12 functional traits of leaves and roots) of Machilus pauhoi seedlings. The responses of leaf and root traits to N addition were analyzed. In addition, the relationships between paired leaf and root traits were analyzed.We found that the responses of the leaves and roots to short-term nitrogen deposition were not consistent. The specific leaf area (SLA) (specific root length, SRL), tissue density (TD), carbon (C) content, N content, C/N, and N/phosphorus (P) of the leaf and root did not appear to respond to N addition. However, the biomass, P content, and C/P of the leaf and root markedly responded to N addition. The nutrient concentrations of the leaf and root were correlated, while the phenotypic traits were not. Furthermore, short-term N addition did not alter the relationship between the leaves and roots.Our results show that, in the context of global change of nitrogen deposition, the correlation between the leaves and roots of a plant has a certain tolerance for nitrogen deposition, which is of great significance for the efficient cultivation of quality seedlings and understanding how terrestrial forest ecosystems respond to nitrogen deposition.

Objective This study aimed to identify the predictors and threshold of failure in neonatal acute respiratory distress syndrome. Methods Newborns with severe acute respiratory distress syndrome aged 0-28 days and gestational age ≥36 weeks were included in the study if their cases were managed with non-extra corporal membrane oxygenation treatments. Patients were divided into two groups according to whether they died before discharge. Predictors of non-extra corporal membrane oxygenation treatment failure were sought, and the threshold of predictors was calculated. Results A total of 103 patients were included in the study. A total of 77 (74.8%) survived hospitalization and were discharged, whereas 26 (25.2%) died. Receiver operating characteristic analysis of oxygen index, pH, base excess, and combinations of these indicators demonstrated the advantage of the combination of oxygen index and base excess over the others variables regarding their predictive ability. The area under the curve for the combination of oxygen index and base excess was 0.865. When the cut-off values of oxygen index and base excess were 30.0 and −7.4, respectively, the sensitivity and specificity for predicting death were 77.0% and 84.0%, respectively. The model with base excess added a net reclassification improvement of 0.090 to the model without base excess. Conclusion The combination of oxygen index and base excess can be used as a predictor of outcomes in neonates receiving non-extra corporal membrane oxygenation treatment for acute respiratory distress syndrome. In neonates with acute respiratory distress syndrome, if oxygen index >30 and base excess

Objective: The aim of the study was to explore the relationship between criticality, brain complications, and immune mechanisms in extracorporeal membrane oxygenation (ECMO) children with pneumonia and severe sepsis. Methods: Patients with simple pneumonia (group I), ECMO patients with pneumonia and severe sepsis accompanied by brain complications (group II), and those without brain complication (group III) admitted to our pediatric intensive care unit were selected to be investigated. The relationship among the peripheral blood subgroups of immune cells, immune factors, adaptive immune responses, endothelial factors, and criticality and brain complications was then studied. Results: Severe paralysis of normal immunity, excess abnormal immunity, and endothelial injury were consistent with the increase in the absolute value of base excess, lactic acid (Lac) content, and average hospitalization days and brain complications involved in group II (vs. group I). The ratio of CD63+ macrophage and CD63+ neutrophil subpopulation increased (p < 0.05); the expression levels of elastase+ neutrophil denatured subgroup (p < 0.05), the ratio of CCR2highCX3CR1low/CCR2lowCX3CR1high of macrophages and neutrophils (p < 0.0001), high-mobility group box 1 (HMGB1), YTHDF1, interleukin-17 protein and mRNA, and RAGE gene decreased to some extent (p < 0.05); the expression levels of Th1 cells chemokine CXCL9 protein and mRNA and sTIE2 protein increased to some extent (p < 0.05); the adaptive immune response of CD8+ CTL stimulated by lipopolysaccharide (LPS) was slightly enhanced (p < 0.05) in group III(vs. group II), which was consistent with the improvement of criticality, average hospitalization days, and the absence of brain complications in group III (vs. group II). Conclusion: ECMO support with brain complication was related to the upregulation of HMGB1 and YTHDF1 protein; the decreased number of CD63+ macrophages and neutrophils; the increased denatured neutrophil subgroup, especially the upregulated ratio of CCR2highCX3CR1low/CCR2lowCX3CR1high of macrophages and neutrophils; the imbalance of Th17/Th1, LPS-specific CD8+ CTL adaptive immune response paralysis; and the reduced endothelial sTIE2 protein expression level which caused clinical deterioration and prolonged average hospitalization days.

A general relationship between the nitrogen (N) and phosphorus (P) content of all plant organs (e.g. leaf, stem, and root) is hypothesized to exist according to whole-plant economics spectrum (PES) theory, but the evidence supporting these expected patterns remains scarce. We measured the N and P content of the leaves, twigs and fine roots of 64 species in three different forest communities along an elevational gradient (evergreen broad-leaved forest, 1319 m a.s.l., coniferous and broad-leaved mixed forest, 1697 m a.s.l., and deciduous forest, 1818 m a.s.l.) in the Wuyishan National Nature Reserve, southeastern China. The scaling relationship between the N and P content and the linear regression relationship between the N:P ratio and N and P content were analysed. The leaf N and P content was significantly higher at the high-elevation site than at the low- or middle-elevation sites (P < 0.001). The N and P content followed a power-law relationship with similar scaling slopes between organs. The N (common slope, 1.13) and P (common slope, 1.03) content isometrically covaried among leaves, twigs and roots. The scaling exponents of the N–P relationship were not significantly different from 1.0 in all organs, with a common slope of 1.08. The scaling constants of N–P decreased significantly (P < 0.05) from the highest value in fine roots (β = 1.25), followed by leaves (β = 1.17), to the lowest value in twigs (β = 0.88). Standardized major axis (SMA) analyses and comparisons of 95 % confidence intervals also showed that the numerical values of the scaling slopes and the scaling constants did not differ regardless of elevation. The N content, but not the P content, accounted for a large proportion of the variation in the N:P ratio in leaves (N:P and N: r2 = 0.31, F = 33.36, P < 0.001) and fine roots (N:P and N: r2 = 0.15, F = 10.65, P < 0.05). In contrast, the N:P ratio was significantly related to both the N and P content in the twigs (N:P and N: r2 = 0.20, F = 17.86, P < 0.001; N:P and P: r2 = 0.34, F = 35.03, P < 0.001, respectively). Our results indicate that different organs of subtropical woody plants share a similar isometric scaling relationship between their N and P content, providing partial support for the PES hypothesis. Moreover, the effects of the N and P content on the N:P ratio differ between metabolic organs (leaves and fine roots) and structural organs (twigs), elucidating the stoichiometric regulatory mechanism of different organs., We found the scaling exponents of the N-P relationship were not significantly different from 1.0 in all organs, with a common slope of 1.08. The numerical values of the scaling slopes and the scaling constants did not differ regardless of elevation. These results indicated the different organs of subtropical woody plants share a similar isometric scaling relationship between their N and P content. Moreover, the effects of the N and P content on the N:P ratio differ between metabolic organs (leaves and fine roots) and structural organs (twigs), elucidating the stoichiometric regulatory mechanism of different organs.

In a controlled experiment, we assessed the effect of phosphate-solubilizing bacterium (PSB) on the soil metal (Cu2+) phytoremediation by Wedelia trilobata and examined the effect of the interaction of Cu contamination and PSB on the growth of W. trilobata. We also explored the effect of the interaction of Cu contamination and PSB on the soil microflora. The results showed that the removal efficiency of Cu from soil by W. trilobata increased with an increase in the concentration of PSB, and the translocation factors of Cu (i.e., leaf:root and stem:root) were both significantly upregulated by PSB. The PSB significantly promoted the growth of W. trilobata; however, the effect of the Cu-PSB interaction on the leaf net photosynthetic rate (Pn) of W. trilobata was not significant, whereas copper contamination had a significant negative influence on the soil microflora, PSB had a significant positive influence on the soil microflora. Thus, PSB improved the phytoremediation efficiency of W. trilobata in Cu-contaminated soil because of the positive influence on the soil microflora, improving soil quality, which then increased the growth of W. trilobata in Cu-contaminated soil. The vigorous growth of W. trlobata led to higher of Cu absorption and translocation from soil as the ultimate result.

Home‐field advantage (HFA) in litter decomposition implies that litter decomposes faster in its ‘home’ habitat, i.e., where the litter originates, than in any other distant (i.e., ‘away’) environment. Soil fauna plays a key role in litter decomposition, while its contribution to HFA may vary greatly. To elucidate how soil fauna interacts with litter quality to influence the occurrence and variability in HFA, leaf litter reciprocal transplant experiments were conducted in the Wuyi Mountains at five different elevations. Naphthalene was used to inhibit soil faunal communities. We found that the magnitude and direction of HFA, and meso- and micro-faunal contributions to HFA varied inconsistently at different elevations. The non-linear direct effects of climate and the variation of soil faunal diversity seemingly led to variations in meso- and micro-faunal contributions to HFA at different elevations. Although HFA was independent of litter quality, meso- and micro-faunal contributions to HFA were significantly related to litter phosphorus. Larger meso- and micro-faunal contributions to decomposition in low leaf litter phosphorus and phosphorus limited habitats may result mainly from the important role of meso- and microfauna in making nutrient-poor soil substrates more accessible to the soil microbial community.

We studied the effect of the microstructure of multiwalled carbon nanotubes (MWCNTs) on interfacial interaction in seven kinds of MWCNT/natural rubber (NR) composites. Unexpectedly, the degree of defects (ID/IG) of MWCNTs was found to play a key role in the interfacial interaction of MWCNT/NR composites. The content of bound rubber (BR) of the composites almost linearly increased with the increase in the ID/IG of MWCNTs. Then we studied the interfacial interaction between MWCNTs with high degree of defects and NR. Interestingly, the BR of the composites consisted of loosely adsorbed BR (LBR) and tight BR (TBR). TBR occupied about half of the total BR, and cannot be removed by extraction in hot toluene for 48 h. Meanwhile, the mobilities of macromolecules in TBR were more restricted than those in LBR. We discussed in depth the molecular origin of the interfacial interaction between defected MWCNTs and NR, and then proposed that LBR was topologically confined by the steps-like structure of defected MWCNTs whereas TBR was principally chemically bonded to MWCNTs. This study provided new insight on the interfacial interaction between MWCNTs and NR and thus provides guidance for the preparation of high-performance elastomer composites with strong interfacial interaction.

Acute respiratory distress syndrome (ARDS) is a multifactorial, inflammatory lung injury disease with high morbidity and mortality. However, the underlying pathogenic mechanism remains unknown. In this study, lipopolysaccharide (LPS)-stimulated alveolar epithelial cells were used to mimic the inflammatory pathogenesis of ARDS in vitro. We here investigated the role of miR-424 in LPS-stimulated alveolar epithelial cells and found it to be substantially downregulated. Overexpression of miR-424 inhibited apoptosis and inflammation in LPS-stimulated alveolar epithelial cells, and the miR-424 inhibitor exhibited the opposite effect. A bioinformatic analysis revealed a potential binding site of miR-424 in the 3'-UTR of fibroblast growth factor 2 (FGF2). A luciferase reporter assay suggested that miR-424 targeted FGF2 in alveolar epithelial cells. The level of FGF2 protein was inhibited by miR-424 mimic, whereas was significantly upregulated after miR-424 suppression in LPS-stimulated alveolar epithelial cells. MiR-424 also exhibited the protective role in LPS-induced apoptosis and inflammation by directly targeting FGF2 via the NF-κB pathway. In conclusion, our results demonstrate that miR-424 had a protective role in LPS-induced apoptosis and inflammation of alveolar epithelial cells by targeting FGF2 via regulating NF-κB pathway. This might contribute novel evidence to help identify a therapeutic target for treating ARDS.

Pediatric sepsis is frequently a fatal condition and a major cause of death globally. The mortality rate of sepsis remains high despite that the advanced therapeutic methods have been carried out. Our research aims to investigate the potentials of miR-34a in the treatment of pediatric sepsis. Results indicated that miR-34a was up-regulated in Lipopolysaccharide (LPS)-induced pulmonary macrophages and U937 cell lines. In addition, miR-34a silence reduced the production of iNOS through inactivating STAT3 pathway in U937 cell lines and cecal ligation and puncture (CLP)-induced lung tissues. Besides, high expression of iNOS and STAT3 in cells transfected with miR-34a mimic further validated it. Furthermore, in vivo experiment demonstrated that miR-34a silence protected CLP-induced suckling rats from lung injury. All in all, our study demonstrated that miR-34a promoted iNOS secretion from pulmonary macrophages in LPS-induced sepsis suckling rats through activating STAT3 pathway. These results provided a possibility to convert miR-34a into clinical application.

Empirical studies indicate that the exponents governing the scaling of plant respiration rates (R) with respect to biomass (M) numerically vary between three‐fourth for adult plants and 1.0 for seedlings and saplings and are affected by nitrogen (N) and phosphorus (P) content. However, whether the scaling of R with respect to M (or N and P) varies among different phylogenetic groups (e.g., gymnosperms vs. angiosperms) or during the growing and dormant seasons remains unclear. We measured the whole‐plant R and M, and N and P content of the seedlings of four woody species during the growing season (early October) and the dormant season (January). The data show that (i) the scaling exponents of R versus M, R versus N, and R versus P differed significantly among the four species, but (ii), not between the growing and dormant seasons for each of the four species, although (iii) the normalization constants governing the scaling relationships were numerically greater for the growing season compared to the dormant season. In addition, (iv) the scaling exponents of R versus M, R versus N, and R versus P were numerically larger for the two angiosperm species compared to those of the two gymnosperm species, (v) the interspecific scaling exponents for the four species were greater during the growing season than in the dormant season, and (vi), interspecifically, P scaled nearly isometric with N content. Those findings indicate that the metabolic scaling relationships among R, M, N, and P manifest seasonal variation and differ between angiosperm and gymnosperm species, that is, there is no single, canonical scaling exponent for the seedlings of woody species.

Physiological and photosynthetic responses were investigated at three different depths of groundwater (DGW: 1.4, 2.4, and 3.4 m) in Elaeagnus angustifolia L., a locally adapted tree to the arid region in northwest China. Predawn leaf water potential and chlorophyll content declined gradually with the increasing DGW, whereas there was little effect on predawn variable-to-maximum chlorophyll fluorescence ratio F v/F m and leaf carotenoid compositions (xanthophyll cycle pool, neoxanthin, lutein, and β-carotene). Net photosynthetic rate (P n), quantum yield of PSII electron transport (ΦPSII), stomatal conductance (Gs), and intercellular CO2 concentration (Ci) declined obviously; however, P n decreased more than ΦPSII at deeper DGW. The photoinhibition of PSII at all three DGW occurred at midday in summer and increased as DGW increased. The ΔpH-dependent thermal dissipation and the level of de-epoxidation of the xanthophyll cycle at all three DGW reached their maxima at midday with the increase of light intensity. However, the fraction of functional PSII and light intensity at deeper DGW (2.4, 3.4 m) showed a negative correlation. This correlation suggested that most of violaxanthin was converted into zeaxanthin at midday, and the reversible inactivation of partial PSII reaction centers took place at deeper DGW. These results together suggest that both the xanthophyll cycle-dependent thermal dissipation and the reversible inactivation of partial PSII might have played important roles in avoiding the excess light-induced energy damage in leaves of this tree species at deeper DGW.

α,α-Disubstituted amino acid derivatives are synthesized either by a self-regeneration of stereocenter strategy or using the asymmetric Strecker reaction/alkylation method. Of the four types of substrates tested for intramolecular acylation, those with a 4-alkoxyl group do not react, those with a 4-bromo substituent give lower conversions, while those without a 4-substituent or with a 4-methyl group work well to give the desired cyclization products. Based on these investigations, a new route for preparing (S)-1-aminoindan-1,5-dicarboxylic acid (S)-AIDA and its analogues was developed.

The antioxidant activities on oil of natural phenolic components extracted from Dalbergia odorifera T. Chen were investigated. A new benzophenone 2,4-dihydroxy-5-methoxybenzophenone ( 1 ), together with eight known components, were isolated. The eight components were identified by chemical and spectroscopic methods as 2′,3′,7-trihydroxy-4′-methoxyisoflavanone ( 2 ), 3′-methoxydaidzein ( 3 ), 4′,5,7-trihydroxy-3-methoxyflavone ( 4 ), vestitol ( 5 ), medicarpin ( 6 ), hexanoic acid, 2-propenylester ( 7 ), hexadecanoic acid, ethyl ester ( 8 ) and 3,8,-nonadien-2-one ( 9 ). Their antioxidant activities were investigated and compared with butylated hydroxyluene (BHT) and α-tocopherol. The results showed that components 1 , 3 , 5 and 6 had antioxidant activity and components 2 and 4 had strong antioxidant activity at 0.02 and 0.04% levels. When the individual components (0.02%) were mixed with 0.02% BHT, or 0.02% α-tocopherol, their protection factor was increased, but there was no synergistic effect. When the individual component had 4 ppm added Fe 3+ , components 1 , 2 , 3 and 4 had antioxidant activity. Their antioxidant activities were tested by an oxidative stability instrument (OSI) at 100°C. Six of the phenolic components showed antioxidant activities.

Two new alkaloidal glycosides, canthin-6-one-5-o-beta-D-xylopyranosyl- (1 --> 6)-beta-D-glucopyranoside (1) and canthin-6-one-1-o-beta-D-xylopyranosyl- (1 --> 6)-beta-D-glucopyranoside (2) named ailantcanthinosides A and B, were isolated from the root bark of Ailanthus altissima. Their structures were elucidated by one-and two-dimensional (1)H NMR, (13)C NMR, FAB-MS, HRESI-MS spectra and chemical methods.

Photosynthesis-irradiance (PI) curves are extensively used in field and laboratory research to evaluate the photon-use efficiency of plants. However, most existing models for PI curves focus on the relationship between the photosynthetic rate (Pn) and photosynthetically active radiation (PAR), and do not take account of the influence of environmental factors on the curve. In the present study, we used a new non-competitive inhibited Michaelis-Menten model (NIMM) to predict the co-variation of Pn, PAR, and the relative pollution index (I). We then evaluated the model with published data and our own experimental data. The results indicate that the Pn of plants decreased with increasing I in the environment and, as predicted, were all fitted well by the NIMM model. Therefore, our model provides a robust basis to evaluate and understand the influence of environmental pollution on plant photosynthesis.

The pyrrolizidine alkaloids, senkirkine ( 1) and doronine ( 2) were isolated from the aerial parts of EMILIA SONCHIFOLIA.