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11.
The average height of 31-aged Robinia pseudoacacia plantation in west mountain of Beijing is 7 in and the mean breastheight diameter of tree is 8.3 cm. The number of tree per hectare appears 1750. The canopy coverage of plantation shows 0.5. Using tile diameter square at tree breast height times tree height (D2H), as an independing variable, to estimate the dry weight of various parts of trees, between them the significient correlations occur. According to the modle of Wstem=58.88(D2H)0.88 (WBranch)=e7.77+0.001(D2H) (Wleaf)=e5.71+0.0008(D2H) (Wroot)=e7.67+0.0009(D2H) 28.45 t/ha of the stem biomass, 11.6 t/ha of the branch biomass. 0.97 t/ha of the leaf biomass, 7.6 t/ha of the root biomass are estimated in arbor layer. The aboveground and belowground biomass of shrub and herb layers axe 13.71 t/ha and 10.72 t/ha respectively in September, the biomass of shrub and herb layer is 24.43 t/ha. 73.05 t/ha of the total biomass in Robinia pseudoacacia plantation is obtained.  相似文献   
12.
High accumulation and selective delivery of boron into tumor tissues are the most important requirements to achieve efficient neutron capture therapy of cancers. We focused on liposomal boron delivery system to achieve a large amount of boron delivery to tumor. We succeeded in the synthesis of the double-tailed boron cluster lipids 4a–c and 5a–c, which has a B12H11S-moiety as a hydrophilic function, by S-alkylation of B12H11SH with bromoacetyl and chloroacetocarbamate derivatives of diacylglycerols. Size distribution of liposomes prepared from the boron cluster lipid 4b, dimyristoylphosphatidylcholine, polyethyleneglycol-conjugated distearoylphosphatidylethanolamine, and cholesterol was determined as 100 nm in diameter by an electrophoretic light scattering spectrophotometer. Calcein-encapsulation experiments revealed that these boronated liposomes are stable at 37 °C in fetal bovine serum solution for 24 h.  相似文献   
13.
We investigated the composition of the vegetation in two former mining regions in Central Slovakia: Banská Štiavnica with predominant Pb-Zn contamination and Staré Hory with a very high Cu content in the soil. Old heaps rich in heavy metals are covered with specific vegetation. On the Cu-rich spoil heaps, species-poor plant communities with prevailing Agrostis stolonifera, Avenella flexuosa, Acetosella vulgaris, Arabidopsis arenosa, Silene dioica, and S. vulgaris occur. Species such as Agrostis capillaris, Acetosella vulgaris, Arabidopsis arenosa, and Thlaspi caerulescens appear frequently on Pb-Zn mine wastes. Several differences in the vegetation structure were detected between the Pb-Zn and Cu mine heaps; higher amounts of vascular plants and fewer lichen species covered the Pb-Zn mine heaps. For the Cu mine heaps, on the contrary a small number of vascular species but a high number and coverage of lichen species, especially Ceratodon purpureus and Cladonia arbuscula subsp. mitis were typical. The non-metalliferous meadows in the vicinity of the mines showed uniform structure but a higher species diversity.  相似文献   
14.
Niemann-Pick type C2 (NPC2) proteins in arthropods have been extensively differentiated and possibly duplicated according to environmental conditions and are probable to have different functions. The participation of NPC2 proteins in chemical communication in arthropods brings new objectives in environmental-friendly strategies for pest population control. In this study, NPC2 gene in Macrocentrus cingulum (McinNPC2) was newly identified by rapid amplification cDNA ends (RACE) technology. McinNPC2 amino acid sequence alignment with other representative NPC2 annotates to evaluate the highly conserved consensus amino acids, but with odorant binding proteins in M. cingulum show that only one consensus amino acid. Primary six-cysteine structures that are same to odorant binding proteins in M. cingulum were observed in McinNPC2. Phylogenetic analysis of McinNPC2 indicated that the nearest monophyletic group forming one clade with high posterior probability values clusters as Cyphomyrmex costatus (CcosNPC2) whereas the nearest evolutionary relation group as some odorant binding proteins. Moreover, quantitative real-time PCR (qPCR) measurements show that the McinNPC2 gene expression level in various tissues of the female is significantly and ubiquitously higher than in male, whereas the highest expression level in female antennae. We further explore the binding characterization of recombinant McinNPC2 to candidate odor molecules and did the modeling and docking simulations. The results showed ligands binding specificity and docking tests results indicate that β-ionone, an aroma compound commonly found in essential oils, can strongly bind with McinNPC2. In conclusion, we proposed that McinNPC2 may be involved in chemical communication and play roles in perception of plant volatiles.  相似文献   
15.
北长山岛森林乔木层碳储量及其影响因子   总被引:3,自引:0,他引:3  
石洪华  王晓丽  王嫒  刘振英  麻德明 《生态学报》2013,33(19):6363-6372
人工林是庙岛群岛典型的陆地生态系统的组成部分,对维护海岛地区生态环境具有重要作用。采用现有生物量相对生长方程和样地调查数据相结合的方法,以庙岛群岛中北长山岛为研究区,对海岛黑松纯林与黑松×刺槐混交林两种林型的碳储量进行了估算,并分析了土壤质地及其理化性质对海岛乔木层碳储量的影响。结果表明:黑松乔木层平均碳储量为84.00 t/hm2,接近于世界平均水平(86.00 t/hm2);黑松×刺槐混交林乔木层平均碳储量为29.60 t/hm2,高于山东省乔木层的平均碳储量(27.62 t/hm2)。应用因子分析法研究影响乔木层碳储量的主要因子,结果表明:土壤质地、pH值、含水量及含盐量是影响海岛乔木碳储量重要的影响因子。北长山岛土壤全氮、总磷、土壤有机质、碳氮比等其他理化性质对乔木层碳储量影响不是非常明显。  相似文献   
16.
Corn leaf aphid Rhopalosiphum maidis (Fitch) can feed on various cereal crops and transmit viruses that may cause serious economic losses. To test the impact of both host plant species and age on R. maidis, as well as the proteomic difference of diverse populations, we first investigated the survival and reproduction of six R. maidis populations (i.e., LF, HF, GZ, DY, BJ, and MS) via a direct observation method in the laboratory on 10 and 50 cm high maize seedlings, and 10 cm high barley seedlings. Then a proteomic approach was implemented to identify the differentially expressed proteins from both aphids and endosymbionts of BJ and MS populations. Results indicated that the BJ population performed significantly better than the others on both barley and 50 cm high maize seedlings, while no population could survive on 10 cm high maize seedlings. The proteomic results demonstrated that the expression levels of myosin heavy chain (muscle isoform X12) (spot 781) and peroxidase (spot 1383) were upregulated, while ATP-dependent protease Hsp 100 (spot 2137) from Hamiltonella defensa and protein SYMBAF (spot 2703) from Serratia symbiotica were downregulated in the BJ population when compared to expression levels of the MS population. We hypothesize that the fatalness observed on 10 cm high maize seedlings may be caused by secondary metabolites that are synthesized by the seedlings and the MS population of R. maidis should be more stress-resistant than the BJ population. Our results also provide insights for understanding the interaction between host plants and aphids.  相似文献   
17.
AimsThis study was conducted to investigate the associations between single nucleotide polymorphisms (SNPs) of matrix metalloproteinases (MMPs) and Kawasaki disease (KD) in the Korean population.Main methodsA total 0f 101 KD patients and 306 healthy controls were examined. MMP7 (rs10502001, G/A, Arg77His), MMP11 (rs738792, T/C, Ala38Val), MMP12 (rs652438, A/G, Ile357Val) and MMP26 (rs2499953, A/G, Lys43Glu) genes were genotyped from the genomic DNA using direct sequencing. The results were then analyzed using logistic regression models, adjusting for gender as covariates.Key findingsThe four SNPs were in Hardy–Weinberg equilibrium. Only the MMP11 polymorphism (rs738792) was associated with KD. The SNP (rs738792) showed a statistically significant association with KD in the codominant (OR = 1.61, 95% CI = 1.11–2.34, P = 0.011) and dominant (OR = 1.92, 95% CI = 1.21–3.06, P = 0.006) models. However, there was no association between polymorphisms of other MMP genes and KD.SignificanceOverall, the results of this study indicate that MMP11 polymorphism may be associated with KD in the Korean population.  相似文献   
18.
19.
Multi‐functional microRNAs (miRNAs) are emerging as key modulators of plant–pathogen interactions. Although the involvement of some miRNAs in plant–insect interactions has been revealed, the underlying mechanisms are still elusive. The brown planthopper (BPH) is the most notorious rice (Oryza sativa)‐specific insect that causes severe yield losses each year and requires urgent biological control. To reveal the miRNAs involved in rice–BPH interactions, we performed miRNA sequencing and identified BPH‐responsive OsmiR396. Sequestering OsmiR396 by overexpressing target mimicry (MIM396) in three genetic backgrounds indicated that OsmiR396 negatively regulated BPH resistance. Overexpression of one BPH‐responsive target gene of OsmiR396, growth regulating factor 8 (OsGRF8), showed resistance to BPH. Furthermore, the flavonoid contents increased in both the OsmiR396‐sequestered and the OsGRF8 overexpressing plants. By analysing 39 natural rice varieties, the elevated flavonoid contents were found to correlate with enhanced BPH resistance. Artificial applications of flavonoids to wild type (WT) plants also increased resistance to BPH. A BPH‐responsive flavanone 3‐hydroxylase (OsF3H) gene in the flavonoid biosynthetic pathway was proved to be directly regulated by OsGRF8. A genetic functional analysis of OsF3H revealed its positive role in mediating both the flavonoid contents and BPH resistance. And analysis of the genetic correlation between OsmiR396 and OsF3H showed that down‐regulation of OsF3H complemented the BPH resistance characteristic and simultaneously decreased the flavonoid contents of the MIM396 plants. Thus, we revealed a new BPH resistance mechanism mediated by the OsmiR396–OsGRF8–OsF3H–flavonoid pathway. Our study suggests potential applications of miRNAs in BPH resistance breeding.  相似文献   
20.
A selective kanamycin-binding single-strand DNA (ssDNA) aptamer (TGGGGGTTGAGGCTAAGCCGA) was discovered through in vitro selection using affinity chromatography with kanamycin-immobilized sepharose beads. The selected aptamer has a high affinity for kanamycin and also for kanamycin derivatives such as kanamycin B and tobramycin. The dissociation constants (Kd [kanamycin] = 78.8 nM, Kd [kanamycin B] = 84.5 nM, and Kd [tobramycin] = 103 nM) of the new aptamer were determined by fluorescence intensity analysis using 5′-fluorescein amidite (FAM) modification. Using this aptamer, kanamycin was detected down to 25 nM by the gold nanoparticle-based colorimetric method. Because the designed colorimetric method is simple, easy, and visible to the naked eye, it has advantages that make it useful for the detection of kanamycin. Furthermore, the selected new aptamer has many potential applications as a bioprobe for the detection of kanamycin, kanamycin B, and tobramycin in pharmaceutical preparations and food products.  相似文献   
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