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1.
Western Hubei is the most concentrated area of forest resources in Hubei Province, and the knowledge of the distribution characteristics of ecosystem carbon density is important to understand the regional characteristics of carbon density and its mechanism of formation. Carbon density and factors influencing different layers in the ecosystem were studied by using field data. The average carbon density of ecosystems in western Hubei was 159.05 t/hm2; the carbon density of different forest types in descending order was Abies fargesii forests (362.25 t/hm2), mixed broadleaf-conifer forests (154.13 t/hm2), broad-leaved forests (146.09 t/hm2), and coniferous forests (135.76 t/hm2), and ecosystem carbon density increased with increasing age. The carbon density of the arborous layer, shrub layer, and soil layer of A. fargesii forests was significant higher than that of the other forests (P < 0.05), indicating the carbon storage per unit area of A. fargesii forests, which grow at higher elevations, was the greatest. The carbon density in arborous layers of broad-leaved forests, mixed broadleaf-conifer forests, and coniferous forests was 39.29 t/hm2, 48.99 t/hm2, and 48.39 t/hm2, respectively. Those of the soil layer were 102.96 t/hm2, 100.97 t/hm2, and 82.37 t/hm2, respectively, and there were no significant differences among them. Among the three forest types, carbon density in the litter layer was greater than that of the shrub layer, which indicated the litter layer plays an important role in carbon storage. The carbon density of mixed broadleaf-conifer forests was greatest, excluding A. fargesii forests, in medium (58.71 t/hm2) and mature forests (79.66 t/hm2). Thus, the carbon sink of mixed broadleaf-conifer forests had more potential than the others at the medium and mature forest stage. The soil layer carbon density in different forests constituted 60.67—70.48% of the entire ecosystem, and was 1.70—2.62 times greater than that of the arborous layer. There are many factors influencing ecosystem carbon density, which result from the interaction of environmental and topographical factors. The main explanatory variables of carbon density of the region were altitude, precipitation, and canopy density. The vegetation and soil layer carbon density increased as altitude increased, and the rate of change for every vertical 100 m was 1.3 t/hm2 and 1.9 t/hm2, respectively (P < 0.05). Although the annual average precipitation only affected the carbon density of the vegetation, it increased to 4 t/hm2 (P < 0.01) when average precipitation was >100 mm.  相似文献   

2.
《Journal of Asia》2014,17(1):67-71
While screening for cellulase-producing fungi from insect gut, a fungus with high endoglucanase (carboxymethyl cellulase; CMCase) activity was isolated from the larval gut of Bombyx mori. Based on morphological characteristics and using an 18S rRNA-based molecular phylogenetic approach, the fungus, strain BMC-2, was identified as a Mucor sp. expressing a novel alkalotolerant cellulase. The maximum production of cellulase by the BMC-2 strain was observed at 55 °C and pH 8.0. The CMCase activity was inhibited by Cu2 + > Na+ > Zn2 + > Mg2 + > Ba2 +, and induced by Ca2 +, Mn2 +, Fe2 +, and K+.  相似文献   

3.
The Golgi ion homeostasis is tightly regulated to ensure essential cellular processes such as glycosylation, yet our understanding of this regulation remains incomplete. Gdt1p is a member of the conserved Uncharacterized Protein Family (UPF0016). Our previous work suggested that Gdt1p may function in the Golgi by regulating Golgi Ca2 +/Mn2 + homeostasis. NMR structural analysis of the polymannan chains isolated from yeasts showed that the gdt1Δ mutant cultured in presence of high Ca2 + concentration, as well as the pmr1Δ and gdt1Δ/pmr1Δ strains presented strong late Golgi glycosylation defects with a lack of α-1,2 mannoses substitution and α-1,3 mannoses termination. The addition of Mn2 + confirmed the rescue of these defects. Interestingly, our structural data confirmed that the glycosylation defect in pmr1Δ could also completely be suppressed by the addition of Ca2 +. The use of Pmr1p mutants either defective for Ca2 + or Mn2 + transport or both revealed that the suppression of the observed glycosylation defect in pmr1Δ strains by the intraluminal Golgi Ca2 + requires the activity of Gdt1p. These data support the hypothesis that Gdt1p, in order to sustain the Golgi glycosylation process, imports Mn2 + inside the Golgi lumen when Pmr1p exclusively transports Ca2 +. Our results also reinforce the functional link between Gdt1p and Pmr1p as we highlighted that Gdt1p was a Mn2 + sensitive protein whose abundance was directly dependent on the nature of the ion transported by Pmr1p. Finally, this study demonstrated that the aspartic residues of the two conserved motifs E-x-G-D-[KR], likely constituting the cation binding sites of Gdt1p, play a crucial role in Golgi glycosylation and hence in Mn2 +/Ca2 + transport.  相似文献   

4.
The aim of the present study was to assess the effects of different organic and inorganic fertilizers on the functional diversity of soil microbial community under a vegetable production system. The Biolog® Eco-plate technique and indices, such as average well-colour development (AWCD), McIntosh and Shannon diversity were employed to study the diversity of soil microorganisms. The AWCD, i.e. overall utilization of carbon sources, suggested that different organic treatments had a significant impact on the metabolic activity of soil microorganisms. After 120 h, the highest AWCD values were observed in poultry manure (2.5 t·ha?1) + vermicompost (3.5 t·ha?1) (0.63) and farm yard manure (FYM) (10 t·ha?1) + vermicompost (3.5 t·ha?1) (0.61). After 72 h, the highest value of the McIntosh diversity index was recorded in poultry manure (2.5 t·ha?1) + vermicompost (3.5 t·ha?1) (3.87), followed by poultry manure (2.5 t·ha?1) + vermicompost (3.5 t·ha?1) + biofertilizers (Azotobacter 500 g·ha?1 applied as seed treatment) (3.12). In the case of the Shannon diversity index, the highest values were noticed in organic treatments; however, there was no significant differences between organic and inorganic treatments. Biplot analysis showed a clear differentiation of organic treatments from the inorganic control. The amino acids, phenolics and polymer utilizing microorganisms were dominant in organic treatments. Inorganic control recorded the lowest values of the microbial diversity indices. Through this study, we have identified the best combination of organic nutrients, i.e. poultry manure (2.5 t·ha?1) + vermicompost (3.5 t·ha?1) for the stimulation of metabolically active soil microbial communities.  相似文献   

5.
The aim of the present study was to analyse the soil properties in different seasons at varying altitudes. The study was carried out in Dhanaulti forest, falls under temperate region of Garhwal Himalaya in Uttarakhand State, India. Physical properties and chemical properties of the soil were estimated using all standard procedures. In the present study, sand particles were reported highest (77.21%) in rainy season followed by in summer (70.17%) and winter (63.15%) seasons. The silt and clay particles also followed similar trend as sand which reduced in order of rainy > summer > winter seasons. The water holding capacity of soil ranged from 62.13 to 67.70%. The majority of soils were dark brown to dark yellowish brown in colour, which is considered having higher potential of water holding capacity. The values of nitrogen ranged between 0.01 to 0.012% (upper altitude), 0.009 to 0.011% (middle altitude) and 0.007 to 0.011% (lower altitude). The effects of altitudes and seasons in nitrogen show significant variation. Potassium ranged between 102.29 and 206.22 kg ha? 1. The combined effect of season and soil-depth also showed significant variation in level of potassium. The soil organic carbon values were between 0.14 and 0.19% and pH values ranged between 6.33 and 6.75 which was slightly acidic in nature.  相似文献   

6.
We studied the interaction effects of 8-different land uses systems viz., forestry (T1), silvopastoral (T2), horticulture (T3), agrihorticulture (T4), agrisilviculture (T5), agrihortisilviculture (T6) > grassland (T7) and agriculture (T8) in 2-altitudinal gradient for three consecutive soil layers of up to 1 m deep from sub-montane to low hill sub-tropical zone of Western Himalayas in Himachal Pradesh State of India. All the land uses under agroforestry practices viz., agrisilviculture, silvopastoral, agrihorticulture and agrihortisilviculture showed significantly enhanced values of pH, organic carbon (OC %), available N, P, K and exchangeable Ca, Mg and available S than agriculture land use. A maximum value of soil carbon (1.08%) was observed in forest land use followed by silvopastoral, horticulture, agrihorticulture, agrisilviculture, agrihortisilviculture, grassland and agriculture, respectively. Overall highest values of available N, P and K were observed under forest land use and silvopastoral among agroforestry systems. Available N, P, and K declined with increasing altitude. Exchangeable Mg followed the trend T7 > T2 > T5 > T1 > T6 > T3 > T4 > T8 and available Sulphur as T7 > T3 > T2 > T6 > T5 > T4 > T8 > T1, respectively. The value of exchangeable Ca and available S increased with increasing altitude. From the study it can be concluded that tree based land use systems of subtropical zone of the Himalayan region are more sustainable and environment friendly than agriculture and grassland use systems. Hence, they need to be conserved and promoted on large scale. The outcome of this paper will be helpful in convincing the farmers for adoptions of agroforestry practices in large scale.  相似文献   

7.
Realizing the importance of forest carbon monitoring and reporting in climate change, the present study was conducted to derive spectrally modeled aboveground biomass and mitigation using Landsat data in combination with sampled field inventory data in the coniferous forests of Western Himalaya. After conducting preliminary survey in 2009, 90 quadrats (45 each for calibration and validation) of 0.1 ha were laid in six forest types for recording field inventory data viz. diameter at breast height, height, slope and aspect. Biomass carbon (Mg ha 1) was worked out for different forest types and crown density classes (open with 10–40% crown density and closed with > 40% crown density) using recommended volume equations, ratios and factors. Biomass carbon map (aboveground + belowground) was generated for the entire region using geospatial techniques. Normalized difference vegetation index (NDVI) was generated and spectral values were extracted to establish relation (R2 = 0.72, p < 0.01) with the field inventory data. The model developed was validated (R2 = 0.73, p < 0.01) with 45 sample observations not used earlier for predicting and generating biomass carbon map (2009) for the entire region. The data from field based inventory indicates highest total biomass carbon (171.40, σ ± 23.19) Mg ha 1 for Fir–Spruce (closed) which has relatively more mature girth classes and low tree density. This value was found to be significantly higher than other forest types. Lowest biomass carbon was observed for Blue Pine (open) (37.15, σ ± 11.82) Mg ha 1. The NDVI values for the entire region ranged from 0 to 0.62 and consequently the spectrally derived aboveground biomass carbon varied from 0 to 600 Mg ha 1. The study demonstrates the application of mapping, spectral responses and sampled field inventory for type wise assessment of carbon mitigation in temperate coniferous forests of Himalayas.  相似文献   

8.
《Ecological Indicators》2008,8(5):657-663
Northeastern region (NER) of India, one of the largest reserves of forests in India has so far been studied with a view to map the distribution of species or modeling the disturbance regimes and richness analysis. The present study focuses on the importance of regional level studies where the entire NER which is under the threat of forest fragmentation and degradation, is been assessed. In the present study, six historical data sets generated from remote sensing data (1972, 1982, 1987, 1989, 1993 and 1999) are used to assess forest cover loss, shape index and entropy to the degree of forest fragmentation over a multi-decadal period. The assessments have been carried out in the open (40–10% canopy density) and close (>40% canopy density) forest cover classes. The range of shape index and deviation from the actual mean in open forest and closed forest were computed separately. The patches among two categories were further analyzed based on patch area into six classes; ranging from <1 km2 to >500 km2. This also indicates variability of the forest patches. It is noteworthy that patches of area within 1–10 km2 and 10–50 km2 have been severely fragmented. This loss could be attributed to the shifting cultivation practice where the patches of moderate size are cultivated by group of families. The present study could give an insight to the patch configuration and composition in terms of shape index and the Shannon's entropy index.  相似文献   

9.
A moderately thermophilic, strictly anaerobic, chemoautotrophic bacterium, designated strain HS1857T, was isolated from a deep-sea hydrothermal vent at the Noho site in the Mid-Okinawa Trough. Strain HS1857T grew between 35 and 63 °C (optimum 55 °C), in the presence of 10–55 g l?1 NaCl (optimum 25 g l?1), and pH 5.5–7.1 (optimum 6.4). Growth occurred with molecular hydrogen as the electron donor and elemental sulfur, nitrate, or selenate as the electron acceptors. Formate could serve as an alternative electron donor with nitrate as an electron acceptor. During growth with nitrate as the electron acceptor, strain HS1857T produced ammonium and formed a biofilm. CO2 was utilized as the sole carbon source. The G + C content of the genomic DNA was 33.2 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain HS1857T is a member of the order Nautiliales, showing a sequence similarity of 95.0% with Lebetimonas acidiphila Pd55T. The fatty acid composition was similar to that of L. acidiphila, which was dominated by C18:0 (47.0%) and C18:1 (23.7%). Based on the genomic, chemotaxonomic, phenotypic characteristics, the name Lebetimonas natsushimae sp. nov., is proposed. The type strain is HS1857T (= NBRC 112478T = DSM 104102T).  相似文献   

10.
Hsp31 protein, belonging to the DJ-1/ThiJ/PfpI superfamily, increases the survival of Escherichia coli under various stresses. While it was reported as a holding chaperone, Hsp31 was also shown to exhibit the glyoxalase III activity in subsequent study. Here, we describe our finding that Hsp31 undergoes a Zn+ 2-mediated multimerization (HMWZinc), resulting in an enhanced chaperone activity. Furthermore, it was shown that the formation of HMWZinc is reversible such that the oligomer dissociates into the native dimer by EDTA incubation. We attempted to determine the structural change involving the transition between the native dimer and HMWZinc by adding Ni+ 2, which is Zn+ 2-mimetic, producing a potential intermediate structure. An analysis of this intermediate revealed a structure with hydrophobic interior exposed, due to an unfolding of the N-terminal loop and the C-terminal β-to-α region. A treatment with hydrogen peroxide accelerated HMWZinc formation, so that the Hsp31C185E mutant rendered the formation of HMWZinc even at 45 °C. However, the presence of Zn+ 2 in the catalytic site antagonizes the oxidation of C185, implying a negative role. Our results suggest an unprecedented mechanism of the enhancing chaperone activity by Hsp31, in which the reversible formation of HMWZinc occurs in the presence of heat and Zn+ 2 ion.  相似文献   

11.
A key series of vinblastine analogs 713, which contain modifications to the C20′ ethyl group, was prepared with use of two distinct synthetic approaches that provide modifications of the C20′ side chain containing linear and cyclized alkyl groups or added functionalized substituents. Their examination revealed the unique nature of the improved properties of the synthetic vinblastine 6, offers insights into the origins of its increased tubulin binding affinity and 10-fold improved cell growth inhibition potency, and served to probe a small hydrophobic pocket anchoring the binding of vinblastine with tubulin. Especially noteworthy were the trends observed with substitution of the terminal carbon of the ethyl group that, with the exception of 9 (R = F vs H, equipotent), led to remarkably substantial reductions in activity (>10-fold): R = F (equipotent with H) > N3, CN (10-fold) > Me (50-fold) > Et (100-fold) > OH (inactive). This is in sharp contrast to the maintained (7) or enhanced activity (6) observed with its incorporation into a cyclic C20′/C15′-fused six-membered ring.  相似文献   

12.
The objective of this study was to estimate sex-specific effects in the test–retest cross-reliability of peripheral and central changes in nonlinear and linear measures of a surface electromyography signal during a brief (5 second) and sustained (2 minute) isometric maximal voluntary contraction, combined with superimposed electrical stimulation involving the ankle plantar flexors over five identical trials. In this study, we repeated the testing protocol used in our previous study of 10 women (age 20.9, SD = 0.3 years) (Bernecke et al., 2015) in a group of 10 men (age 21.2, SD = 0.4 years). Despite the central (sex effect; p < 0.05, ηp2 > 0.71, SP > 70%) and peripheral fatigability (sex effect; p < 0.01, ηp2 > 0.8, SP > 90%) during sustained isometric maximal voluntary contraction, and lower reliability for central activation ratio during brief (intraclass correlation coefficient [ICC] = 0.95 for men and ICC = 0.82 for women) and sustained maximal voluntary contraction (ICC > 0.82 for men and ICC > 0.66 for women) over ankle plantar flexors expressed in women more than in men, all the ICCs of all indices measured by tests assessing neuromuscular function across the five identical test–retest trials were found as meaningful (correlation significance of p < 0.05 was reached) and no significant differences were found between trials for any of the measured variables. In conclusion, the present study demonstrated greater central and peripheral fatigue for female participants following sustained (2 minute) isometric maximal voluntary contraction of the plantar flexor muscles for all repeated trials and indicated an acceptable agreement between measurements of the characteristic variables made using the three different devices (dynamometry, electrical stimulation, and surface electromyography) over time for both sexes.  相似文献   

13.
Cedrus deodara and Sabina chinensis are widely planted in North China. The needles of C. deodara and S. chinensis were sampled in the urban, suburban, and rural districts of Tianjin where the atmospheric conditions are significantly different according to the environmental monitoring results. The Cu, Mn, Zn, and Pb concentrations in the samples were examined via ICP. The resistance indexes, and the malonic aldehyde (MDA), soluble sugar, and free proline levels were also determined. The Pearson coefficients between the resistance indexes and the heavy metal contents were analyzed to compare the two plants abilities to accumulate heavy metal and their resistance characteristics. The results indicated that the heavy metal concentrations had the following significant trend: urban areas > suburban areas > rural areas. In urban areas, the Mn, Zn, and Pb concentrations in C. deodara were as high as 2024.77 mg·kg? 1, 2397.07 mg·kg? 1, and 130.07 mg·kg? 1, significantly higher than in S. chinensis. The Mn, Zn, and Pb concentrations in C. deodara were extremely significantly positively correlated (P < 0.01), but no significant correlations were noted in S. chinensis. The MDA, soluble sugar, and free proline concentrations in C. deodara increased as the heavy metal contents rose along the urban–rural gradient, and were positively correlated with the plant heavy metal contents. They were much higher than the contents in S. chinensis where no differences were noted among the sampling sites. In conclusion, the heavy metal resistance methods used by C. deodara and S. chinensis are different. C. deodara could absorb and accumulate many heavy metals, mainly through increased physiological resistance to stress. In contrast, S. chinensis resistance relied on avoiding contact with the metals and by reducing absorption. These differences are associated with the biological characteristics of C. deodara and S. chinensis, and are closely connected with their coniferous and morphological differences.  相似文献   

14.
The aim of this study was to analyze the effectiveness of different control agents of Aedes aegypti and Aedes albopictus associated with ovitraps under laboratory and field conditions. Five treatments were used: grass infusion + Bacillus thuringiensis israelensis (gI + Bti), grass infusion + Saccharopolyspora spinosa (gI + Ss), grass infusion + Pyriproxyfen (gI + P), distilled water + Toxorhynchites haemorrhoidalis (dW + Th), and grass infusion (gI) (control). The highest mean number of eggs of both species were obtained with grass infusion in the laboratory. Among control agents, the lowest mean of A. aegypti eggs occurred with gI + Ss and the lowest mean of A. albopictus eggs occurred with dW + Th. There was no difference between treatments in A. aegypti (P = 0.4320) and A. albopictus (P = 0.7179). In the field, the highest mean number of eggs for both species were obtained with gI + Ss, and the lowest values were obtained with gI + P (P = 0.0124). The treatments can be applied to both the surveillance and the control, but ovitraps with biological larvicide Bti were more effective and safer considering the number of eggs laid and selectivity of pathogens for mosquitoes.  相似文献   

15.
Studies on ecosystem service function have an important significance for analyzing and understanding global warming. With the introduction of geographic information system (GIS) and remote sensing (RS) technologies for the evaluation of ecosystem service function, the scope for analysis has been widening. Increasing number of researchers use these technologies to quantify the value of ecosystem service functions and reveal their spatial-temporal variability. By using the data for the interpretation of five RS images and net primary productivity (NPP) in Qinghai Lake basin, we assessed the value of vegetation carbon fixation and oxygen release services and revealed their dynamic variation in this basin. The result suggested that the average values of vegetation carbon fixation and oxygen release services in Qinghai Lake basin between 1987 and 2010 were spatially distributed in a ring shape around the Qinghai Lake and decreased from southeastern to the north and northwestern regions; the northwestern areas had the lowest value. The vegetation carbon fixation value between 1987 and 2010 was on an average 28.87 × 108 yuan/a in Qinghai Lake basin, whereas the oxygen release value was 64.41 × 108 yuan/a. Alpine meadow ecosystem showed the highest value of vegetation carbon fixation and oxygen release services function in Qinghai Lake basin, with average values of 18.28 × 108 yuan/a and 40.79 × 108 yuan/a, respectively, followed by those of temperate steppe and sparse vegetation. The vegetation carbon fixation and oxygen release values in Qinghai Lake basin gradually increased from 1987 to 2010, with the maximum value in 2010. By the end of 2010, the values increased by 7.19 × 108 yuan and 16.04 × 108 yuan, respectively. The values slightly decreased in barren land, lakeside marsh, river valley swamp, and sandy areas, but increased to different degrees in other ecosystems. Among them, the largest increase was noted in alpine meadow (4.38 × 108 yuan and 9.78 × 108 yuan, respectively), followed by those in temperate steppe with increased values of 1.12 × 108 yuan and 2.49 × 108 yuan, respectively.  相似文献   

16.
Hepatic injury is the major limitation of long-term albendazole administration in patients with cystic echinococcosis (CE), which could give rise to cessation of treatment. The objective of the present study was to evaluate the protective effects of Zataria multiflora aromatic water (AW) against the hepatic injury induced by long-term albendazole treatment in mice with CE. Fifty healthy BALB/c female mice were infected intraperitoneally by injection of 1500 protoscoleces per animal. Five months after infection, the infected animals were divided into five treatment groups including Z. multiflora (40 ml/l in drinking water for 90 days), albendazole (200 mg/kg/day for 90 days), Z. multiflora + albendazole 200 (40 ml/l Z. multiflora and 200 mg/kg/day albendazole for 90 days), Z. multiflora + albendazole100 (40 ml/l Z. multiflora and 100 mg/kg/day albendazole for 90 days), and untreated (control) group. At the end of the treatment period, anesthesia was performed and blood samples were collected directly from the heart prior to euthanasia. Liver variables and oxidative stress markers were measured in the blood serum samples. A decrease in serum liver enzyme activity in the both Z. multiflora + albendazole groups was observed when compared to control, Z. multiflora and albendazole groups; however, the results for Z. multiflora + albendazole 100 were significant (p < 0.007) and superior compared to those for Z. multiflora + albendazole 200. No significant differences for oxidative stress markers were observed between the different groups. The results of the present study revealed that a combined therapy with Z. multiflora AW and albendazole is effective against hepatic injury induced by CE and/or long term albendazole administration in mice with cystic echinococcosis.  相似文献   

17.
A loop-mediated isothermal amplification (LAMP) technique has been widely used in detecting the nucleic acid of various pathogenic bacteria. In this study, a set of four LAMP primers was designed to specifically test Anaplasma bovis. The LAMP assay was performed at 62 °C for 60 min in a water bath. The specificity was confirmed by amplifying A. bovis isolate, while no cross reaction was observed with other five pathogens (Anaplasma bovis, Anaplasma phagocytophilum, Theileria luwenshuni, Babesia motasi and Schistosoma japonicum). The sensitivity of LAMP was 5 × 100 copies/μL, 100 times more than that of conventional PCR (5 × 102 copies/μL). Of 120 blood DNA extracted from sheep and goats field samples, 81 (67.5%), 22 (18.3%) and 43 (35.8%) were positively detected by LAMP, conventional PCR and nested PCR, respectively. The findings indicated that the developed LAMP assay is a new convenient tool for rapid and cost-effective detection of A. bovis.  相似文献   

18.
A new strain of Manila clam with orange shell color was produced after selection within a full-sib family for two generations. In the present study, the shell length, height, and width, and the live body weight of the orange strain were measured, and their correlation coefficients were calculated. The shell morphological traits were used as independent variables, and the live body weight was used as the dependent variable for calculating the path coefficients, correlation index, and determination coefficients. The results showed that the correlation coefficients between each shell morphological trait and the live body weight were all highly significant (P < 0.01). The correlation indices (R2) of morphological traits against the live body weight of clams were larger than 0.85, indicating that the morphology traits were the main factors affecting the body weight. Multiple regression equations were obtained to estimate shell length X1 (cm), shell height X2 (cm), and shell width X3 (cm) against live body weight Y (g): Y = ? 2.62 + 0.34 X1 + 0.145 X2, (X1 < 0.05, X2 < 0.05). The results suggest that the shell length could be used as the main trait for selective breeding and could indirectly make a large improvement in the weight trait.  相似文献   

19.
To investigate the possible interactive effects of elevated atmospheric ozone (O3) concentrations and periodic drought stress on physiology of Shantung maple (Acer truncatum Bung), an experiment was conducted from the growth season of 2012 to 2013 with open-top chambers (OTCs) in Changping district, a suburb of Beijing, China. Four treatments were administered with three replications in twelve OTCs which were NN (well watered + ambient air), NO (well watered + add 100 nl l? 1 O3 above ambient air), DN (drought stress + ambient air) and DO (drought stress + add 100 nl l? 1 O3 above ambient air). Leaf area (LA), leaf mass per area (LMA), individual leaf weight (ILW), carbon(C), nitrogen (N) and sulfur (S) contents in early and late leaves were measured at the end of the second year. The results showed: (1) Both elevated O3 concentration and drought treatments significantly reduced early leaf LMA, LA, ILW, leaf N and S contents, with a reduction of 28.7, 45.7, 61.3, 39.6, 16.1% by O3 stress and 12.5, 46.8, 53.5, 15.45 and 22% by drought stress, respectively, while only LMA of late leaf was reduced 12.1% by O3 treatments and LA and ILW were significantly reduced 23.3% and 30% by drought treatments. (2) Significant interactions of elevated atmospheric O3 concentration and mild drought were detected on LMA, LA, ILW, N and C contents in early leaves and LMA in late leaves. Except for LA, the decreases under interactive treatments were all less than independent O3 effects. In conclusion, late leaf had less responses to elevated O3 and drought stresses than early leaves which need to be considered separately. The interactive effects suggested drought had antagonistic effects with O3 on growth indicators except for LA, indicating drought could mitigate the adverse efforts from O3 effects.  相似文献   

20.
Store-operated Ca2 + entry (SOCE) mediated by stromal interacting molecule-1 (STIM1) and Orai1 represents a major route of Ca2 + entry in mammalian cells and is initiated by STIM1 oligomerization in the endoplasmic or sarcoplasmic reticulum. However, the effects of nitric oxide (NO) on STIM1 function are unknown. Neuronal NO synthase is located in the sarcoplasmic reticulum of cardiomyocytes. Here, we show that STIM1 is susceptible to S-nitrosylation. Neuronal NO synthase deficiency or inhibition enhanced Ca2 + release-activated Ca2 + channel current (ICRAC) and SOCE in cardiomyocytes. Consistently, NO donor S-nitrosoglutathione inhibited STIM1 puncta formation and ICRAC in HEK293 cells, but this effect was absent in cells expressing the Cys49Ser/Cys56Ser STIM1 double mutant. Furthermore, NO donors caused Cys49- and Cys56-specific structural changes associated with reduced protein backbone mobility, increased thermal stability and suppressed Ca2+ depletion-dependent oligomerization of the luminal Ca2 +-sensing region of STIM1. Collectively, our data show that S-nitrosylation of STIM1 suppresses oligomerization via enhanced luminal domain stability and rigidity and inhibits SOCE in cardiomyocytes.  相似文献   

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