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1.
2000a间,中国境内野生稻分布区域由2495575km2缩减至1371094km2,减少了45.06%;分布纬度北界由38°3′N南移至28°14′N,南移9°49′、1140km;中国境内栽培稻分布区域由4081860km2增加至9600000km2,增加了135.00%;分布北界由38°N北移至53°29′N,北移15°29′、1700km。人口分布重心主要在黄河流域和长江流域,对该区域野生稻的生存产生不利影响。而促进栽培稻的发展,必须建立野生稻自然保护区。  相似文献   

2.
2000a间,中国境内野生稻分布区域由2495575km2缩减至1371094km2,减少了45.06%;分布纬度北界由38°3′N南移至28°14′N,南移9°49′、1140km;中国境内栽培稻分布区域由4081860km2增加至9600000km2,增加了135.00%;分布北界由38°N北移至53°29′N,北移15°29′、1700km。人口分布重心主要在黄河流域和长江流域,对该区域野生稻的生存产生不利影响。而促进栽培稻的发展,必须建立野生稻自然保护区。  相似文献   

3.
本文采用生命表和数值模型分析等方法,对中国卤虫(Artemiasinica)的温度特性做了研究。1.孵化发育起始温度9.07℃,幼虫发育起始温度9.07℃。有效积温(℃·d)前者为0.921±0.979,后者为205.26±24.1,平均世代有效积温458.4±39.6。2.各项生命表参数均与温度呈显著的函数关系,其适温范围基本介于18─34℃,最适点介于26.5─28.5℃,种群增长倍数>2的温度范围在18─34℃。3.在山西盐池水域,该卤虫的年世代数为6.2±0.62个世代、第2─5个世代是种群生产力高峰期。在此期间种群的加倍时间<15d.内禀增长率>0.04d ̄(-1),因此资源开发价值最大  相似文献   

4.
香石竹的叶片培养及植株再生   总被引:14,自引:0,他引:14  
1植物名称香石竹(Dianthuscaryophy-llus),别名康乃馨。2材料类别无菌苗叶片。3培养条件以MS为基本培养基。分化培养基附加:(1)6-BA1.0mp·L-1(单位下同)+NAA0.3;(2)6-BA1.0+NAA0.1;(3)6-BA1.0+NAA0.05。增殖培养基附加6-BA0.5+NAA0.1。分化和增殖培养基均加蔗糖3%、琼脂0.7%,pH5.8。生根培养基为1/2MS附加NAA0.1,蔗糖2%,琼脂0.6%,pH5.8。培养温度为(25±1)℃,光照12h·d-1,…  相似文献   

5.
银杏光合与蒸腾特性的研究   总被引:24,自引:0,他引:24  
通过测定银杏净光合速率、蒸腾速度、气孔阻力等生理指标和观测银杏叶片形态、解剖特征,结果表明:1.银杏光补偿点为76μmol.m^-1.s^-1,光饱和点为1040μmol.m^-2.s^-1。超过光饱和点后,随光照强度增加光合强度反而下降。2.银杏光合最佳温度为26℃。3.净光 速率的日变化呈“午休”型的双峰曲线变化,最高峰出现在10:00A.M.前后,次峰出现在6:00P.M.前后。4.蒸腾速度  相似文献   

6.
为探讨温度对胸腺激素促NK活性的影响,用胸腺因子D、胸腺素和胸腺肽与白介素2联合诱导LAK细胞,以LDH释放法检测其NK活性,发现:140℃以下加热处理的胸腺激素与未加热者活性无明显差异,当加热150℃以上时,其所诱导的NK活性,胸腺因子D、胸腺素和胸腺肽分别由62.4±5.4%降至48.2±7.6%%、53.3±3.1%降至44.4±2.6%和由60.5±4.4%降至46.7±2.9%,结果表明,150℃以上温度可使胸腺激素促NK活性丧失。  相似文献   

7.
本文详细研究了适合块状耳霉变异株Et107生长的营养因子及培养条件。C/N比为15∶1时有利于菌株的生长,尿素是菌株生长的最佳氮源,生物素及适量的Fe(2+)促进菌株生长,无机元素Mg是菌株生长不可缺少的因素。最适生长pH范围为6.0~7.0,最适生长温度为25±1℃,通气量(即装液量)以70ml/250ml为宜。  相似文献   

8.
银杏叶黄酮提取方法比较   总被引:19,自引:0,他引:19  
比较不同溶剂提取银杏(GinkgobilobaL.)叶黄酮类化合物的提取效率,从成本效益角度考虑,以70%乙醇作为提取溶剂更为有利。在分级沉淀中,黄酮含量与蛋白质含量呈正相关,在乙醇提取液中黄酮和蛋白质含量最高;蛋白质的存在有助于提高黄酮的溶解度。乙醇提取液用饱和(NH4)2SO4浓缩两次,可使醇相中的黄酮沉淀析出。根据试验结果,提出了银杏叶黄酮的优化提取方法。  相似文献   

9.
蕲蛇酶在健康人的药物代谢动力学   总被引:3,自引:0,他引:3  
王晴川  刘广芬 《蛇志》1997,9(3):14-15
健康自愿者14人,男9人,女5人,除研究者本身(女,64岁)外,平均年龄25.8±s6.5岁,分3组。分别一次iv蕲蛇酶注射液1U(150),2U(300)和3U(450μg)。用ELISA方法检测药后不同时间血药浓度以研究药代动力学。结果显示血药-时间曲线符合二室开放模型,其t1/2α分别为0.66±0.10,0.97±0.34和1.22±0.77h,t1/2β分别为15.95±2.4,18.80±4.94和19.73±4.28h  相似文献   

10.
通过计算机模拟比较十种理论上柔性较好的接头在 5′ I L6 T N FΔ融合蛋白中对 I L 6 和 T N FΔ空间结构的影响情况,从中选择了 S A P G T P接头.以 S A P G T P 作为接头的 5′ I L6 S A P G T P T N FΔ和以 P G 为接头的5′ I L6 P G T N FΔ空间结构预测结果相似. D N A 序列分析两种蛋白的接头序列均与设计的一致.5′ I L6 S A P G T P T N FΔ和 5′ I L6 P G T N FΔ蛋白的大肠杆菌表达产物经初步分离、纯化及鉴定后,生物学活性及对高表达 I L 6 受体肿瘤细胞的杀伤作用比较结果显示:在 L929细胞上,前者的生物学活性是后者的 27 倍;在 U937 细胞上,前者对肿瘤细胞的抑制率是后者的13 倍.它们对高表达 I L 6 受体的 U937 细胞杀伤作用分别是同样突变位点的人 T N Fα衍生物的37 和 29 倍.实验表明, S A P G T P作为接头构建的 5′ I L6 S A P G T P T N FΔ融合蛋白优于以 P G 作为接头构建的 5′ I L6 P G T N FΔ融合蛋白.  相似文献   

11.
The ISO-standard for LCA distinguishes four phases, of which the last one, the interpretation, is the least elaborated. It can be regarded as containing procedural steps (like a completeness check) as well as numerical steps (like a sensitivity check). This paper provides five examples of techniques that can be used for the numerical steps. These are the contribution analysis, the perturbation analysis, the uncertainty analysis, the comparative analysis, and the discernibility analysis. All five techniques are described at a non-technical level with respect to basic concept, possibilities, tabular and graphical representation, restriction and warnings, and all are illustrated with a simple example.  相似文献   

12.
影响水稻光合日变化的酶和相关因素的分析   总被引:13,自引:0,他引:13  
水稻叶片的最大光合速率出现在上午10:00时,Rubisco初始活力也在此时达到最大,然后逐渐降低,下午14:00时略上升后又下降.Rubisco初始活力与光合速率之间极显著相关,相关系数为 0.9474.运用相关性分析、回归分析、通径分析,对晴(有时有云)天气水稻叶片的光合速度、光合关键酶及有关因素的日变化进行综合评估,结果发现中午光合下降主要来自气孔限制,同时Rubisco活性也下降;Rubisco活性是影响光合日变化的又一重要生化因子.体内Rubisco活性受Rubisco活化酶的调节.  相似文献   

13.
Pyrolysis mass spectrometry (PyMS) is a rapid, simple, high-resolution analytical method based on thermal degradation of complex material in a vacuum, and has been widely applied to the discrimination of closely related microbial strains. Minimally prepared samples of embryogenic and non-embryogenic calluses derived from various higher plants (sweet potato, morning glory, Korean ginseng, Siberian ginseng, and balloon flower) were subjected to PyMS for spectral fingerprinting. A dendrogram based on the unweighted pair group method, with arithmetic mean of pyrolysis mass spectra, divided the calluses into Siberian ginseng embryogenic callus and the others, which were subsequently divided into embryogenic and non-embryogenic callus groups, regardless of plant species from which the calluses were derived. In the non-embryogenic callus group, the dendrogram was in agreement with the known taxonomy of the plants. These results indicate that PyMS analysis could be applied for discriminating plant calluses based on embryogenic capacity and taxonomic classification.  相似文献   

14.
We studied vegetative and reproductive characters of 74 herbarium specimens of Licuala glabra Griff. (Palmae) collected from 22 localities throughout Peninsular Malaysia. To test the null hypothesis that there are no distinct groups within the species, cluster analysis (nearest neighbour), principal coordinates and principal components analyses were performed on the set of 43 qualitative and quantitative characters. The results obtained suggested that: (1) there are three infraspeciflc groups within the species, viz., the two published varieties glabra and selangorensis as well as a possible third novel taxon; (2) there is clustering of individuals corresponding to their geographic localities; (3) clusters generated using only reproductive characters indicate a biogeographic distribution of populations correlated with the mountain ranges in the peninsula.  相似文献   

15.
Synopsis Principal components analysis was performed on fish presence/absence data for 39 common fish species from 410 stream sites in Kansas. The analysis confirmed ten ecologically meaningful fish assemblages, based on species associations. Factor scores based on these assemblages were then clustered into six geographic areas or fish ecoregions. Canonical discriminant analysis identified environmental variables that distinguished the derived fish ecoregions. Mean annual runoff, mean annual growing season, and discharge appear most important. Mean width, mean depth, chloride concentration, water temperature, substrate type, gradient, and percent of pool habitat were less important. Correspondence exists between these fish ecoregions and the patterns of physiographic regions, river basins, geology, soil, and potential natural vegetation in Kansas. The multivariate statistical approach used to classify fish ecoregions should have considerable potential value for fish assessment and management purposes in areas other than the state of Kansas.  相似文献   

16.
In an active-controlled trial, the experimental treatment can be declared to be non-inferior to the control if the confidence interval for the difference excludes a fixed pre-specified margin. Recently, some articles have discussed an alternative method where the data from the current study and placebo-controlled studies for the active control are combined together into a single test statistic to test whether a fixed fraction of the effect of the active control is preserved. It has been shown that, conditional on nuisance parameters from the active-controlled study, a fixed margin can be defined that will be operationally equivalent to this latter method. In this article, we will discuss statistical properties associated with these approaches. Specifically, the interim monitoring boundaries and level of evidence will be considered.  相似文献   

17.
The most common tests for types and antitypes in configural frequency analysis are normal approximations of exact tests. In the paper such statistics under the complete independence model and under the fixed margins model are discussed. It turns out that these test statistics are not acceptable when the number of simultaneously performed tests is large or when the expected frequencies are small. In these cases, the use of exact tests is advocated and some existing computer programs for such tests are indicated. A normal approximation based on the strong version of the De Moivre-Laplace limit theorem is also discussed. Empirical examples are given from longitudinal data describing psychological development of boys.  相似文献   

18.
Heat is a major abiotic stress that drastically reduces chickpea yield. This study aimed to identify heat-responsive traits to sustain crop productivity by screening a recombinant inbred line (RILs) population at two locations in India (Ludhiana and Faridkot). The RIL population was derived from an inter-specific cross between heat-tolerant genotype GPF 2 (C. arietinum L.) and heat sensitive accession ILWC 292 (C. reticulatum). The pooled analysis of variance showed highly significant differences for all the traits in RILs and most of the traits were significantly affected by heat stress at both locations. High values of genotypic coefficient of variation (19.52–38.53%), phenotypic coefficient of variation (20.29–39.85%), heritability (92.50–93.90%), and genetic advance as a percentage of mean (38.68–76.74%) have been observed for plant height, number of pods per plant, biomass, yield, and hundred seed weight across the heat stress environments. Association studies and principal component analysis showed a significant positive correlation of plant height, number of pods per plant, biomass, hundred seed weight, harvest index, relative leaf water content, and pollen viability with yield under both timely-sown and late-sown conditions. Path analysis revealed that biomass followed by harvest index was the major contributor to yield among the environments. Both step-wise and multiple regression analyses concluded that number of pods per plant, biomass and harvest index consistently showed high level of contribution to the total variation in yield under both timely-sown and late-sown conditions. Thus, the holistic approach of these analyses illustrated that the promising traits provide a framework for developing heat-tolerant cultivars in chickpea.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-00977-5.  相似文献   

19.
分子水平的遗传多样性及其测量方法   总被引:20,自引:1,他引:19  
遗传多样性水平是一项很重要的数据。目前从分子水平量化遗传多样性的方法以等位酶分析、RFLP分析和RAPD分析为代表。遗传变异在基因组中并非随机分布,所以取样方式对分析结果的影响不容忽视。本文叙述了遗传变异的产生和分布,并以此为基础比较了上述3种分析方法的理论与实践。  相似文献   

20.
凡纳滨对虾各月龄性状的主成分与判别分析   总被引:8,自引:0,他引:8  
何铜  刘小林  杨长明  黄皓  相建海 《生态学报》2009,29(4):2134-2142
为了研究凡纳滨对虾各性状增长规律和判定最佳生长季节凡纳滨对虾的体格与月龄的关系,选择1~6月龄凡纳滨对虾各1000只,选择全长、体长、第一腹节背高、第三腹节背高、第一腹节背宽、头胸甲长和体重共7个性状,进行主成分与判别分析.结果表明:各月龄凡纳滨对虾性状之间均呈现显著的正相关(P<0.01), 其中以全长与体长的相关性最为明显,1月龄凡纳滨对虾体重与形态性状的相关系数较小.各月龄凡纳滨对虾的主成分有所不同,1~2月龄凡纳滨对虾的第一主成分为长度因子,第二主成分为宽度因子,第三主成分为高度因子;3月龄凡纳滨对虾的第一主成分与1~2月龄凡纳滨对虾一致,但第二主成分为高度因子,第三主成分为体重因子;4~6月龄凡纳滨对虾的第一主成分为体重因子,第二主成分为高度因子,第三主成分为宽度因子.1~3月龄凡纳滨对虾形态性状的增长优先于体重, 4~6月龄凡纳滨对虾体重优先于形态性状的增长.错过最佳生长季节的凡纳滨对虾的与体格大小相符的月龄可通过建立的判别式来判断,总的判别准确率为98.98%,其中2~4月龄凡纳滨对虾的判别准确率为100%.  相似文献   

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