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51.
天津滨海盐渍土上几种植物的热值和元素含量及其相关性   总被引:21,自引:1,他引:21  
研究了天津开发区滨海防护圈9种植物的热值,灰分含量和元素含量以及他们之间的相关关系。结果表明:平均干重热值和去灰分热值都表现为乔木(18442.72J/g、19136.23J/g)>灌木(18138.18J/g、18701.295J/g)>多年生草本(15643.11J/g、18622.185J/g)>1年生草本(13119.33J/g、17907.91J/g)。具体数值随植物种和组分的不同而异。从植物的元素含量看,常量元素N、P、K在乔木的根、枝、皮中含量较干高;在灌木中N和P表现为根>枝,K则反之;而多年生草本地上部分和地下部分含量较接近,对于本研究区土壤主要盐分元素Na,Ca,Mg,Cl^-而言,乔木基本与常量元素N、P、K一致,仍是根、皮、枝含量高于干;灌木均为根<枝,与K一样,和N、P相反。多年生草本除大米草Ca含量外都是地上部分含量比地下部分高。植物碳含量总体上根的含量低于其他组分。植物的干重热值与碳含量呈极显著的正相关关系,与灰分含量及Na,Mg,Cl^-含量呈极显著的负相关关系,与Ca含量呈显著负相关关系,去灰分热值与碳含量和干重热值呈极显著的正相关关系。  相似文献   
52.
取小孢子处于单核靠边期的烟草8611、K326、NC89花蕾,经4℃预处理48小时后用不同剂量的 ̄(60)COγ射线辐射,将花药接种于H培养基中诱导出单倍体植株,并经壮苗培养,移栽成活后,在幼苗新叶上摩擦接种黄瓜花叶病毒病(CMV)汁液,经过92天的选择、淘汰,分别在NC89、8611植株群体中筛选得到了各2株、1株抗CMV的突变体植株。  相似文献   
53.
Whether to commit limited cellular resources toward growth and proliferation, or toward survival and stress responses, is an essential determination made by Target of Rapamycin Complex 1 (TORC1) for a eukaryotic cell in response to favorable or adverse conditions. Loss of TORC1 function is lethal. The TORC1 inhibitor rapamycin that targets the highly conserved Tor kinase domain kills fungal pathogens like Candida albicans, but is also severely toxic to human cells. The least conserved region of fungal and human Tor kinases are the N-terminal HEAT domains. We examined the role of the 8 most N-terminal HEAT repeats of C. albicans Tor1. We compared nutritional- and stress responses of cells that express a message for N-terminally truncated Tor1 from repressible tetO, with cells expressing wild type TOR1 from tetO or from the native promoter. Some but not all stress responses were significantly impaired by loss of Tor1 N-terminal HEAT repeats, including those to oxidative-, cell wall-, and heat stress; in contrast, plasma membrane stress and antifungal agents that disrupt plasma membrane function were tolerated by cells lacking this Tor1 region. Translation was inappropriately upregulated during oxidative stress in cells lacking N-terminal Tor1 HEAT repeats despite simultaneously elevated Gcn2 activity, while activation of the oxidative stress response MAP kinase Hog1 was weak. Conversely, these cells were unable to take advantage of favorable nutritional conditions by accelerating their growth. Consuming oxygen more slowly than cells containing wild type TOR1 alleles during growth in glucose, cells lacking N-terminal Tor1 HEAT repeats additionally were incapable of utilizing non-fermentable carbon sources. They were also hypersensitive to inhibitors of specific complexes within the respiratory electron transport chain, suggesting that inefficient ATP generation and a resulting dearth of nucleotide sugar building blocks for cell wall polysaccharides causes cell wall integrity defects in these mutants. Genome-wide expression analysis of cells lacking N-terminal HEAT repeats showed dysregulation of carbon metabolism, cell wall biosynthetic enzymes, translational machinery biosynthesis, oxidative stress responses, and hyphal- as well as white-opaque cell type-associated genes. Targeting fungal-specific Tor1 N-terminal HEAT repeats with small molecules might selectively abrogate fungal viability, especially when during infection multiple stresses are imposed by the host immune system.  相似文献   
54.
为明确不同水旱轮作模式对川西平原旱作季杂草群落特征的影响,从而为旱作季杂草的高效防控提供理论依据。基于大蒜-水稻(GR)、小麦-水稻(WR)、蚕豆-水稻(BR)、油菜-水稻(RR)和马铃薯-水稻(PR)五种水旱轮作的长期定位试验,在2022年旱季采用生态学方法探究了不同水旱轮作模式下旱作季农田杂草种类、密度、株高、生物量等杂草群落结构和物种多样性特征。结果表明:(1)五种轮作模式下杂草田间密度表现为WR>BR>RR>GR>PR,生物量表现为WR>BR>GR>RR>PR,物种多样性表现为GR>BR>RR>PR>WR,物种均匀度表现为GR>PR>BR>RR>WR,群落优势度表现为WR>PR>RR>BR>GR,表明GR杂草群落稳定性最高,WR杂草群落稳定性最低且优势物种发生危害的程度最高,RR的杂草种类数少且不易发生危害;(2)五种水旱轮作模式杂草群落相似性较高,相似性指数在0.69-0.84之间,WR杂草生活型以一年生单子叶杂草为主,其余四种模式以一年生双子叶杂草为主;(3)WR优势杂草种类最少,为禾本科棒头草(Polypogon fugax Nees ex Steud),其重要值为59.53%;BR优势杂草种类最多,为棒头草、蔊菜(Rorippa indica (L.) Hiern)、毛茛(Ranunculus japonicus Thunb)和通泉草(Mazus japonicus (Thunb.) O. Kuntze);GR优势杂草为苣荬菜(Sonchus wightianus DC)和猪殃殃(Galium spurium L); RR和PR优势杂草均为三种,都包括为棒头草和蔊菜。因此,以确保旱作季杂草能得到有效控制,不同水旱轮作模式应制定不同的杂草防控措施。GR和PR应重点控制以猪殃殃为代表的双子叶杂草,WR应着重控制以棒头草等为代表的单子叶杂草,BR和RR应注重繁殖力强的单双子叶杂草的综合防治。  相似文献   
55.
56.
烟草花药单倍体试管植株Nc89、Nc82、6186,取其完全展开之叶片,切成5mm×5mm大小的叶块,将之接种于补加BA(2mg/L)、蔗糖(5%)、琼脂(0.55%),pH5.8的MS培养基中,然后将其置于23—25℃、12h/d光照的培养间中培养,大致经过14—18天后,在叶外植体边缘部分出现了肉眼可见的绿色小芽,待芽长至约5mm大小时,将其从外植体上分离并置于含1/2 MS大量元素、全量MS微量元素、铁盐及有机物质,并补加KH_2PO_4(50mg/L)、IAA(1mg/L)、蔗糖(3%)、琼脂(0.55%),pH5.8的过渡生根培养基中,待3个星期后芽已长出了3片小叶时再将之转移到含1/2 MS大量元素、MS全量铁盐,并补加IAA(1 mg/L)、蔗糖(1%)、琼脂(0.55%),pH5.8的生根培养基上,5—6天后芽上基部有小根出现,再经过两个星期,试管苗长出了较发达的根系。待其长至3cm—4cm高时,移栽入土,移栽后试管苗成活率高,苗长势很好。  相似文献   
57.
China has become the country with the largest resource use and has high levels of waste emissions that pose a great management challenge. To provide more details about environmental problems and to find effective solutions, this article analyzed the scale, structure, and trend of the socioeconomic metabolism in China during the period 1992–2014 based on economy‐wide material flow accounts (EW‐MFA), and predicted resource use during the period of the 13th Five‐Year Plan. The results of this study show that the scale of China's socioeconomic metabolism in China increased more than twofold, during 1992–2014. However, after 2011, with the economic slowdown, the growth rates of total material requirement (TMR), direct material input (DMI), and domestic processed output (DPO) began to decrease. China may reach an inflection point, but this point will probably not be approached before the year 2020. Material recycling (MR) has played an important role in improving resource productivity, improving it by 92.52 renminbi per tonne in 2014. Metallic minerals and fossil fuels are the main sources of hidden flow. Carbon dioxide (CO2) emissions, construction waste, and agricultural emissions have become the major sources of DPO. Because of the 13th Five‐Year Plan, China may slow the growth rate of DMI and may save 10.26 gigatonnes of resources during 2015–2020. Resource productivity is predicted to increase by 15.91%. Imports and MR may play more important roles. These suggestions are made: (1) strengthening the recycling system; (2) stronger policies, especially in metallic mineral and fossil fuels; (3) developing management systems for CO2 emissions, construction waste, and agricultural emissions; and (4) adjusting China's economic structure.  相似文献   
58.
Plumbagin (PL), an active naphthoquinone compound, has been demonstrated to be a potential anticancer agent. However, the underlying anticancer mechanism is not fully understood. In this study, the human hepatocellular carcinoma (HCC) SMMC-7721 cell line was studied in an in vitro model. The cell proliferation was inhibited by PL in a dose- and time-dependent manner. Electron microscopy, acridine orange staining, and immunofluorescence were used to evaluate autophagosome formation and LC3 protein expression in PL-treated SMMC-7721 cells. Real-time polymerase chain reaction and Western blot showed that PL treatment suppressed the expression of apoptosis and autophagy factors (LC3, Beclin1, Atg7, and Atg5), which are associated with tumor apoptosis and autophagy in SMMC-7721 cells. In the study of in vitro tumor nude mouse models, PL can inhibit tumor growth. Cell apoptosis and autophagy of the transplanted tumors were evaluated by hematoxylin and eosin staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining, and Western blot. In addition, in the in vivo studies of HCC cells, we found that pretreatment with the autophagy inhibitor 3-methyladenine blocked the formation of apoptosis induced by PL. In contrast, administration of the apoptosis inhibitor Z-VAD did not affect PL-induced autophagy. Taken together, our findings strongly suggest that PL is a promising drug with significant antitumor activity in HCC.  相似文献   
59.
This study evaluated the effect of prostaglandin E1 (PGE1) on the stability of atherosclerotic plaque. A vulnerable plaque model was established in rabbits, using balloon injury combined with a high-cholesterol diet. The rabbits were distributed into a control group, a low-dose PGE1 treatment group, a moderate-dose PGE1 treatment group, a high-dose PGE1 treatment group, and a simvastatin treatment group, with treatments lasting for 4?weeks. At week 13 (at the end of the experiments), atherosclerotic plaque was triggered by injection of Russell's viper venom (Chinese) and histamine. Serological, pathological, immunohistochemical, and gene-expression studies were subsequently performed. PGE1 treatment did not alter serum lipid levels; however, PGE1 dose-dependently increased the thickness of the fibrous caps, and decreased the plaque vulnerability index. The plaque contents of macrophage- and the mRNA levels of monocyte-chemotactic protein-1, matrix metalloproteinase-1, and matrix metalloproteinase-9 were markedly reduced in all of the PGE1 treatment groups, with the high-dose of PGE1 being more effective than the simvastatin treatment. These findings suggest that PGE1 dose-dependently enhances the stability of atherosclerotic plaque. The high-dose of PGE1 presented more protection in terms of inhibiting macrophage accumulation and inflammatory expression in plaque. Our findings suggest a novel drug for the treatment of atherosclerosis.  相似文献   
60.
Considerable evidence supports that the CD4(+) T cell-mediated immune response contributes to the development of atherosclerotic plaque. However, the effects of Th17 cells on atherosclerosis are not thoroughly understood. In this study, we evaluated the production and function of Th17 and Th1 cells in atherosclerotic-susceptible ApoE(-/-) mice. We observed that the proportion of Th17 cells, as well as Th1, increased in atherosclerotic ApoE(-/-) mice compared with nonatherosclerotic wild-type littermates. In ApoE(-/-) mice with atherosclerosis, the expression of IL-17 and retinoic acid-related orphan receptor γt was substantially higher in the arterial wall with plaque than in the arterial wall without plaque. Increased Th17 cells were associated with the magnitude of atherosclerotic plaque in ApoE(-/-) mice. Importantly, treatment of ApoE(-/-) mice with neutralizing anti-IL-17 Ab dramatically inhibited the development of atherosclerotic plaque, whereas rIL-17 application significantly promoted the formation of atherosclerotic plaque. These data demonstrate that Th17 cells play a critical role in atherosclerotic plaque formation in mice, which may have implications in patients with atherosclerosis.  相似文献   
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