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1.
通过水稻种植田间试验,研究了水稻秸秆直接还田、水稻秸秆与生活垃圾炭化后还田对稻田温室气体CH4、CO2和N2O排放及土壤理化性质和水稻产量的影响.结果表明:与直接还田相比,秸秆炭化后还田可显著降低稻田CH4和N2O的累积排放量,降幅分别为64.2%~78.5%和16.3%~18.4%.与不添加生物炭相比,无论种植水稻与否,添加秸秆炭和垃圾炭均显著降低了稻田N2O的累积排放量;不种植水稻情况下,添加垃圾炭显著降低了稻田CO2的累积排放量,降幅为25.3%.秸秆炭对提高稻田土壤pH和速效钾含量的作用优于垃圾炭.两种生物炭均能显著提高稻田土壤有机碳含量,但对土壤容重、全氮、有效磷、阳离子交换量及水稻籽粒产量均未产生显著影响.与秸秆直接还田相比,秸秆炭化后还田对水稻增产的效果更佳.  相似文献
2.
杭州稻麦菜轮作地区大气氮湿沉降   总被引:2,自引:0,他引:2       下载免费PDF全文
陈义  唐旭  杨生茂  吴春艳  王家玉 《生态学报》2009,29(11):6102-6109
通过雨水中NH+4-N/NO-3-N比率和铵态氮自然丰度值(δ15NH+4)的变化探讨大气氮湿沉降与农作施肥活动的关联性. 2003年6月至2005年7月,采用自行设计定制的雨水收集器在浙江杭州稻-麦-蔬菜轮作地区进行了为期2a的全天候连续雨水采样分析.结果显示,杭州稻-麦-蔬菜轮作地区雨水中NH+4-N/NO-3-N比率和δ15NH+4值呈现相似的季节性变化,雨水中NH+4-N/NO-3-N的峰值出现在6月底~9月上旬,而后逐渐下降,秋冬季(10~11月份)降到最低;来春麦菜集中施肥期(2~3月份),又呈现多个小高峰;5~6月份为单季稻和蔬菜基肥和追肥集中施用期,故而峰值也达4以上;入冬后仅在麦田施肥期出现一个小高峰而后明显下降,大都降到1以下;频繁施肥期雨水中的NH+4-N/NO-3-N比率值是农闲期的2~4倍,显示雨水NH+4-N/NO-3-N比率与农田施肥活动有密切关联与同步性,但与气温无直接关联(R2=0.0129).雨水中δ15NH+4值的变化,与雨水中NH+4-N/NO-3-N比率相似,呈现明显的季节性变化:稻麦生育后期与种前空闲期为正值,麦稻蔬菜集中施肥期转为负值.雨水中NH+4-N/NO-3-N比率与δ15NH+4值对大气湿沉降中氮的来源、形态及地面NH3排放源的强度有一定的表征意义.  相似文献
3.
Hydrogen sulfide alleviates aluminum toxicity in barley seedlings   总被引:1,自引:0,他引:1  

Aims

Aluminum (Al) toxicity is one of the major factors that limit plant growth. Low concentration of hydrogen sulfide (H2S) has been proven to function in physiological responses to various stresses. The objective of this study is to investigate the possible role of H2S in Al toxicity in barley (Hordeum vulgare L) seedlings.

Methods

Barley seedlings pre-treated with sodium hydrosulfide (NaHS), a H2S donor, and subsequently exposed to Al treatment were studied for their effects on root elongation, Al accumulation in seedlings, Al-induced citrate secretion and oxidative stress, and plasma membrane (PM) H+-ATPase expression.

Results

Our results showed that H2S had significant rescue effects on Al-induced inhibition of root elongation which was correlated well with the decrease of Al accumulation in seedlings. Meanwhile, Al-induced citrate secretion was also significantly enhanced by NaHS pretreatment. Al-induced oxidative stress as indicated by lipid peroxidation and reactive oxygen species burst was alleviated by H2S through the activation of the antioxidant system. Moreover, Al-induced reduction in PM H+-ATPase expression was reversed by exogenous NaHS.

Conclusions

Altogether, our results suggest H2S plays an ameliorative role in protecting plants against Al toxicity by inducing the activities of antioxidant enzymes, increasing citrate secretion and citrate transporter gene expression, and enhancing the expression of PM H+-ATPase.  相似文献
4.
pcsk9 siRNA对oxLDL诱导的THP-1源性巨噬细胞凋亡的影响   总被引:1,自引:0,他引:1  
为研究pcsk9基因沉默后对氧化型低密度脂蛋(oxLDL)诱导THP-1源性巨噬细胞凋亡的影响,用不同浓度oxLDL处理THP-1源性巨噬细胞48 h,Hoechst33258染色检测细胞凋亡,RT-PCR、Western blot分别检测pcsk9 mRNA、NARC-1蛋白的表达.应用Lipofectamine2000转染3对pcsk9 siRNAs进THP-1源性巨噬细胞中,筛选出最有效的siRNA再转染入THP-1源性巨噬细胞,24 h后加入oxLDL处理48 h,Hoechst33258染色观察细胞评价细胞凋亡,流式细胞术计数检测细胞凋亡率.结果发现,75 mg/L oxLDL处理THP-1源性巨噬细胞48 h后,Hoechst33258染色可见大量凋亡细胞.同时RT-PCR、Western blot检测发现,pcsk9 mRNA和NARC-1蛋白质表达量均随oxLDL浓度的增加而增加,75 mg/LoxLDL组增加最明显.不同浓度siRNA转染THP-1源性巨噬细胞后,RT-PCR筛选出3对siRNAs的终浓度为80 nmol/L均可出现明显的沉默效应.选取此浓度在蛋白质水平检测基因抑制情况,筛选出最有效的一对siRNA.将筛选出来的siRNA转染细胞24 h后,再用oxLDL处理48 h,Hoechst33258染色及流式细胞计数结果显示,转染siRNA组凋亡明显被抑制.结果表明,在本研究的浓度范围内,随着oxLDL浓度增加pcsk9的表达随之增加,同时,THP-1源性巨噬细胞凋亡也明显增加,75 mg/L oxLDL最明显,pcsk9 mRNA和蛋白质的表达也在该浓度最高.提示pcsk9 siRNA能有效抑制pcsk9基因的表达,从而有效抑制由oxLDL诱导的THP-1源性巨噬细胞的凋亡.  相似文献
5.
草原土壤微生物受放牧的影响及其季节变化   总被引:1,自引:0,他引:1       下载免费PDF全文
以内蒙古克什克腾旗西部的典型草原为对象, 研究轻度放牧区(LG)、中度放牧区(MG)、重度放牧区(HG)土壤中的微生物数量、微生物生物量和土壤呼吸强度的季节变化以及放牧强度对它们的影响。结果表明, 微生物数量、微生物生物量以及土壤的呼吸作用强度均有较明显的季节性变化, 峰值均出现在8月份, 而且三者之间具有极显著的正相关关系; 轻度和中度放牧有利于土壤中的微生物数量、生物量的增加, 而重度放牧则导致土壤中微生物数量和生物量的减少。  相似文献
6.
应用细胞培养技术和四甲基偶氮唑盐(MTT)测定法对高压静电场照射雏鸡血液和免疫器官的T细胞对刀豆蛋白(ConA)的增殖反应及其白细胞介素-2(IL-2)诱生活性的动态变化进行了较全面系统的研究.结果发现,高压正静电场照射雏鸡血液和免疫器官的T细胞增殖功能及其IL-2诱生活性均明显高于高压负静电场照射雏鸡和对照雏鸡;而高压负静电场照射雏鸡血液和免疫器官的上述各项被检指标均不同程度的低于对照雏鸡.表明高压正静电场照射对雏鸡血液和免疫器官的细胞免疫功能及其调节具有促进作用,而高压负静电场照射可使雏鸡血液和免疫器官的细胞免疫功能及其调节减弱或降低.  相似文献
7.
A red–pink, Gram-negative, rod-shaped, non-motile, non-spore-forming bacterium, designated strain DK6-37 was isolated from the permafrost region of Qilian Mountains in northwest of China. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that this isolate represents a novel member of the genus Hymenobacter, with low sequence similarities (<97 %) to recognized Hymenobacter species. Optimum growth was observed at 28 °C, pH 7.0 and 0 % NaCl. The strain was found to contain MK-7 as the predominant menaquinone. The polar lipids were identified as phosphatidylethanolanmine, two unknown aminophospholipids, one unknown aminolipid and three unknown polar lipids. The major fatty acids were identified as summed feature 3 (C16:1 ω7c/C16:1 ω6c as defined by MIDI), summed feature 4 (anteiso-C17:1 B/iso-C17:1 I), C16:1 ω5c, iso-C17:0 3-OH, iso-C15:0 and C18:0. The DNA G + C content was determined to be 67.4 mol %. On the basis of the polyphasic evidence presented, it is proposed that strain DK6-37 represents a novel species of the genus Hymenobacter, for which the name Hymenobacter qilianensis sp. nov. is proposed. The type strain is DK6-37T (= CGMCC 1.12720T = JCM 19763T).  相似文献
8.
Suancai is a traditional fermented food that is still popular in northeastern China. Twenty-four bacterial isolates, obtained from 10 samples of naturally fermented suancai broth via screened cultivation, were found to be lactic acid bacteria by physiological and biochemical testing and 16S rDNA-sequence analysis. Among the isolates, 21 rod-shaped strains were classified as Lactobacillus plantarum (eight strains), Lactobacillus sakei (six strains), Lactobacillus curvatus (five strains), or Lactobacillus paracasei (two strains), while three cocci-shaped isolates were identified as Leuconostoc mesenteroides. These lactic acid bacteria are subjected to salt stress during the fermentation of suancai. In the present study, we examined Lactobacillus paracasei LN-1’s display of salt tolerance. To understand the mechanism involved, a proteomics-based, two-dimensional electrophoresis analysis was undertaken to reveal the response of LN-1 during growth in medium with or without NaCl. Out of 23 protein spots that showed differential changes in expression, seven were identified by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry. Further analysis showed that chaperone proteins (Hsp 60 and Hsp 70) and a fatty acid biosynthesis enzyme (Fab G) possibly play important roles in the ability of Lactobacillus paracasei LN-1 to resist salt stress.  相似文献
9.
为了筛选可用于亚洲栽培稻的重要野生近缘物种颗粒野生稻群体遗传结构研究的有效 SNPs标记,本研究共选取Osgstf3、OsNAC6、BADH、XCP2、EMF2和 ERCC4 6个重要水稻功能基因,检测了来自中国云南和海南12份颗粒野生稻代表样品中的单核苷酸多态性,结果发现Osgstf3、OsNAC6、BADH和XCP2的单核苷酸多态性接近于零,但在 EMF2和ERCC4内含子区中检测到较低的核苷酸变异。利用EMF2和ERCC4片段对来自云南的3个天然群体和来自海南的2个天然群体共52个个体进行了群体遗传学研究,发现该物种具有高水平的遗传分化和低水平的遗传变异的独特群体遗传结构;这种剧烈的遗传分化不仅来自云南和海南两个地区之间,而且还来自地区内居群间,说明该野生稻生长的热带、亚热带森林生境的破坏导致了碎裂的居群间基因流强烈受阻。  相似文献
10.
KAI1, a metastasis-suppressor gene belonging to the tetraspanin family, is known to inhibit cancer metastasis without affecting the primary tumorigenicity by inhibiting the epidermal growth factor (EGF) signaling pathway. Recent studies have shown that hypoxic conditions of solid tumors induce high-level autophagy and KAI1 expression. However, the relationship between autophagy and KAI1 remains unclear. By using transmission electron microscopy, confocal microscopy, and Western blotting, we found that KAI1 can induce autophagy in a dose- and time-dependent manner in the human pancreatic cell line MiaPaCa-2. KAI1-induced autophagy was confirmed by the expression of autophagy-related proteins LC3 and Beclin 1. KAI1 induces autophagy through phosphorylation of extracellular signal-related kinases rather than that of AKT. KAI1-induced autophagy protects MiaPaCa-2 cells from apoptosis and proliferation inhibition partially through the downregulation of poly [adenosine diphosphate (ADP)-ribose] polymerase (PARP) cleavage and caspase-3 activation.  相似文献
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