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1.
长春市主要木本植物汞的污染特征 总被引：6，自引：0，他引：6
研究了长春市主要木本植物杨树、榆树、柳树、油松和落叶松不同器官中的总汞含量。结果表明 ,长春市植物存在着一定程度的汞污染。其中毛白杨、垂柳和油松对汞的吸收能力较低 ,落叶松叶的吸收能力较高 ,榆树吸收汞的能力最高。植物不同器官总汞含量存在着差异 ,除油松外 ,树叶 >树皮 >树茎 ,油松为树叶 >树茎 >树皮 ,各器官总汞含量呈正相关。植物总汞含量的空间特征为公路 >公园 >对照点 ,表明交通是影响植物总汞含量的一个重要因素。植物秋季总汞含量高于春季 ,表明植物在生长季节中累积汞 相似文献
2.
3种植物对重金属富集能力的比较 总被引：1，自引：0，他引：1
以菖蒲(Acorus calamusLinn.)、金叶菖蒲(Acorus gramineus‘Ogon’)和散尾葵(Chrysalido-carpus lutescensH.Wendl)为试验材料,将3种植物定植于人工配置的Cu、Zn、Cr和Pb复合型污染的土壤,研究不同植物对土壤中重金属的富集能力。结果表明:3种植物根部具有较强的吸收与富集作用,除Zn外,其他三种元素在根中的含量要大于茎叶中的含量,表明根系对Cu、Cr和Pb的滞留能力较强;3种植物对Zn的吸收量最大、吸收速率比较高,而对Pb的吸收量最少、吸收速率比较低,表明这3种植物对Zn污染的土壤净化效果最为明显,而对Pb污染土壤净化效果较差。 相似文献
3.
Sheshadri Narayanan 《Indian journal of clinical biochemistry : IJCB》1999,14(1):40-48
The apo E gene located on chromosome 19 in humans is polymorphic. The three apo E isoforms E2, E3, and E4 are coded by three
common alleles of the gene. The amyloid plaques in brains of Alzheimer disease (AD) patients are known to contain apo E. There
is an increased prevalence of E4 allele in AD patients. apo E exhibits increased binding to a peptide Aβ deriving from amylold
precursor protein. apo E, the risk factor for late AD disease is unable to prevent formation of paired helical filaments which
in turn destabilizes neuronal microtubules.
A variety of molecular techniques are available for apo E genotyping using DNA amplified by the polymerase chain reaction
(PCR). The high guanine to cytosine content of apo E is problematic to the extent that the yield of PCR product and hybridization
stringency can be compromised. The specificity of diagnosis of late-onset AD can be improved when results of apo E genotyping
are evaluated together with clinical criteria. 相似文献
4.
陕西省分布着国家保护的珍稀濒危植物44种，其中属国家一级保护1种，二级保护15种，三级保护28种。这些珍稀濒危植物在医药、花卉、化工、木材等方面具有较高的开发利用价值。由于近年来自然和人为等因素的影响，使生态环境遭到严重破坏，许多珍贵稀有植物濒临灭绝。因此，积极保护与合理利用这些资源迫在眉睫。 相似文献
5.
BackgroundAscorbic acid (Asc) is one of the most abundant antioxidants and it serves as a major contributor to protect plants against oxidative damage. Plants use two enzymes that participate in the metabolic recycling of Asc. One of these two enzymes is dehydroascorbate reductase (DHAR). It directly regenerates Asc from its oxidized state and thus prevents Asc from being irreversibly hydrolyzed to 2, 3-diketogulonic acid. This study aimed to examine whether over-expression of DHAR leads to an enhanced oxidative stress tolerance in tobacco plants.ResultsIn this study, we functionally characterized a novel JcDHAR gene from Jatropha curcas and found via quantitative RT-PCR analysis that JcDHAR can be induced with H2O2, salt and PEG stresses. The DHAR activities of transgenic tobacco plants increased from 2.0 to 5.3 fold compared to wild-type plants. As a result, the transgenic plants displayed enhanced tolerance to oxidative stress.ConclusionsOur results indicate that JcDHAR expression can effectively enhance the tolerance to oxidative stress in plants. 相似文献
6.
刺五加的有性生殖与营养繁殖 总被引：4，自引：0，他引：4
刺五加 Eleutherococcus senticosus (Rupr.et Maxim.)Maxim,既可进行有性繁殖,又可进行营养繁殖。本文报道其三类花丝长度不同的植株每个花序的花朵数量、座果率、饱满种子率及根茎形态和形态发生的某些特点。通过人工受精,检测了其繁育系统。结果表明:长花丝植株不座果,短花丝植株座果,但不同年份、不同生境中座果率不同,中花丝植株也座果但饱满种子率教低。在正常年份,短花丝植株的座果率接近40％，并且林缘的座果率稍高于皆伐迹地和次生林下的。考虑到中花丝植株在所研究地区居群数很少，我们认为绝大多数刺五加种子是异花传粉的产物，其有性生殖与营养繁殖相配合，在无人为破坏的前提下，该物种不应该濒危。 相似文献
7.
大豆是一种重要的农产品资源,压榨行业是大豆产业链上的重要环节,它的原料来自大豆种植业,生产的豆粕主要用作饲料业和畜牧业的蛋白原料。自1996年以来,中国大豆进口量不断增加,是全球最大的大豆压榨国,大豆压榨企业布局发生了重大变化。美国和巴西是世界上最大的大豆生产国,也是主要的大豆压榨国,对比分析美国、巴西及中国大豆压榨企业布局特征,对指导中国未来大豆压榨企业投资布局具有重要意义。本文根据项目组20多年持续收集的相关资料,以及美国农业部、巴西植物油加工协会的资料,对比美国、巴西和中国的大豆供求基本特点、大豆生产布局、畜牧业和饲料业分布、大豆压榨企业和产能布局特点发现,美国、巴西的大豆压榨企业主要集中在大豆主产区,并与其国内豆粕市场空间高度重合,呈现“大集聚、小分散”的布局形态;而中国大豆压榨企业布局和大豆制品销区在空间上不完全重合,逐渐形成了以沿海港口城市为压榨核心,以长江、哈大铁路等交通运输线路扩散的带状布局形态。区域畜牧业、饲料业发展决定着豆粕市场需求空间,但是大豆原料供给与豆粕需求在空间上往往存在差异,除了不同国家和区域的产业政策外,大豆原料及豆粕的运费成本、豆粕的市场潜力、区域内大豆压榨产能规模及企业间分工协作所产生的集聚效应是造成大豆压榨企业空间布局形态存在巨大差异的主要原因。 相似文献
8.
9.
为了研究不同油菜基因型小孢子衍生植株倍性水平差异以及秋水仙碱处理对相应植株结实性能影响,本研究利用三个遗传背景各不相同的F1杂交组合,通过小孢子培养产生再生小苗,经FCM检测比较不同基因型染色体的倍性水平;并根据检测结果,选择性地对再生苗进行秋水仙碱加倍处理,分析不同染色体倍性间加倍率和结实性差异.结果表明:倍性水平显示二倍体的再生苗(自然加倍)约占总数的20％～28％,其中60％～80％可发育成正常二倍体植株,故不需要再行加倍处理;倍性为嵌合体的再生苗占45％～60％,未加倍处理平均仅7％植株可长成结荚正常的二倍体,经加倍处理后结实株率平均可从40％提高到75％;根据植株的结实性分析,对相同基因型的角果性状来说,自然加倍产生的正常植株优于加倍处理后产生的二倍体,但秋水仙碱加倍处理明显促进嵌合体植株的角果发育,平均角果长度增加1.2 cm,角果粒数增多4粒左右. 相似文献
10.
燃煤电厂环境污染第三方治理研究 总被引：1，自引：0，他引：1
作为中国环境治理思路由“谁污染谁治理”向“谁污染谁付费”转变的具体实施路径,环境污染第三方治理在雾霾防治等方面得到推广。针对政府如何制定切实可行政策鼓励燃煤电厂实现达标排放、燃煤电厂如何选择清洁发展路径方面存在的问题,以煤电行业烟气治理为研究对象,从绿色供应链的视角,分别构建在4种规制约束-政策激励下燃煤电厂采用自身投资运维、第三方治理2种模式的数学模型,并求解分析。结果显示：规制、激励政策同时实施能帮助燃煤电厂升级为绿色电厂;因提供较少补贴就能帮助燃煤电厂,政府更倾向根据第三方治理模式制定补贴政策;第三方治理模式还能在让燃煤电厂获得更多收益的同时,使传统环保企业转型为能够提供第三方治理的生产性服务企业而获得稳定收益,有助于“谁污染谁付费”思路在实践中的推广。最后,本文提出政府要加强环境约束政策执行、监督力度,给予精准激励政策,并出台鼓励提升环境绩效政策的建议。 相似文献
11.
The “Quan Fang Bei Zu”, a first dictionary for Chinese plants, which contains 27
volumes in its first collection and 31 volumes in its second collection, was completed by
Chen Jing-yi in 1253, the First Year of Bao You of Li Zong in Song Dynasty. The
first part of this encyclopaedia of plants is devoted to flowers. The second part is of
more varied nature, dealing with fruit trees, plants in general, herbs, trees, agriculture
and sericulture, vegetables, and medicinal herbs. These two collections cover 267 kinds
of plants, each of which is described under two categories separately: The first category,
“Si Shi Zu” in Chinese, meaning “facts of the plants” concerned, which again divided
into 3 entries, i.e. the history, miscellaneous information and sundry bits of the plants.
The second category, “Fu Yong Zu” in Chinese, meaning poetry, which divided into
10 meters, wherein the plants are described and eulogized in poetrical expressions.
Later on, the “Quan Fang Bei Zu” was used as a blueprint for some famous books
in China, for example, the “Qun Fang Pu” and the “Guang Qun Fang Pu” all written
and compiled after its model. It is known today that in China there are only two
extant hand writting copies of it, one in Beijing Library, the other in the Library of
Yunnan University. Both of them are listed as the best national books. Outside China,
it is known that a third copy of is in the Congress Library in U.S.A. As for the ori-
ginal wood-carving copy printed during the period of the Song Dynasty, it is known so
far that one copy is kept in the Library of Culture Ministry of Japan. The Beijing
Agriculture Publishing House has made a decision to photograph this carved copy in
the Culture Ministry of Japan as one of the “Precious Series of China Agriculture
Science”. The book plays a very important role in the study of chinese botany, agri-culture science, medicine, history and literature. 相似文献
12.
Modeling the adoption rates of manufacturing technology innovations by small US manufacturers: a longitudinal investigation 总被引：1，自引：0，他引：1
Paul M Swamidass 《Research Policy》2003,32(3):351-366
This study provides conclusive evidence to support the view that small plants are slower than larger plants to adopt manufacturing innovations. This empirical study based on over 1000 US manufacturing plants engaged in producing discrete products, studies the adoption of manufacturing technologies in small plants relative to large plants between 1993 and 1997.Under the assumption that small manufacturers are disadvantaged, several federal and state programs have been created to assist small manufacturers in acquiring and adopting manufacturing innovations. Through quantification of technology adoption in small manufacturing firms, this study’s findings reveal which manufacturing innovations are in greater need of governmental assistance programs. While small plants are making progress over time in catching up with larger plants in computerized technology use, they are not making similar progress in adopting manufacturing technology innovations in soft technologies. Several propositions for future research and recommendations for public policy are offered. 相似文献
13.
林芝地区珍稀濒危藏药植物资源调查与评价 总被引：3，自引：0，他引：3
对西藏林芝地区珍稀濒危藏药植物资源调查分析表明,该区共有35种珍稀濒危藏药材植物,隶属23科33属,占整个西藏高原种类的比例较大,是西藏高原珍稀濒危藏药材植物资源分布的一个缩影。除鸡蛋参、喜马拉雅紫茉莉、卷叶黄精、羊齿天门冬、翼首草、螃蟹甲、窄竹叶柴胡外,其他药材植物地上部分的含水率均大于地下部分的含水率。平均单株生物量方面,暗红小檗最大、为1800g,最小是卷叶黄精、为0．699g。地上部分生物量与地下部分生物量的比值方面,波棱瓜最大、比值为14,最小的是羊齿天门冬、比值仅为0．189。调查分析亦表明,林芝地区珍稀濒危藏药材植物资源储量为3199．29t,单位面积药材植物生物量与海拔关系密切,该区珍稀藏药材植物种类多、生境复杂,分布广、但分布不均,储备量大、经济价值高。建议处理好资源保护与经营发展的关系,建立药用植物生态产业的保护区,加强科学研究、建立种植园,改进药材植物濒危等级的确定。研究和分析结果为该区珍稀藏药材植物资源持续利用提供了理论依据。 相似文献
14.
通过生物勘探活动获得的资源价值是生物多样性价值的主要表现形式之一。本文通过理论建模,对遗传资源物种多样性潜在价值（选择价值）的评估方法进行了探索,并通过数值模拟,尝试性地评估了全中国和案例区高等植物物种多样性的遗传价值。结果显示,中国高等植物具有较高的潜在价值: 边际物种价值为人民币3531万元,潜在总价值约为11 825亿元;以一个面积确定的案例区为例,得到武夷山国家级自然保护区的边际栖息地价值约为6444元/hm2。本文通过修正既有主要模型和参数赋值方法,构建新的潜在价值评估的理论模型和参数,为国内开展遗传资源物种多样性选择价值评估提供了一个全新的方法补充,即基于生物勘探的价值评估。通过数值模拟所形成的研究结论对于未来将遗传资源的潜在价值纳入保护政策制订、引导保护投资、促进生物遗传资源的有效保护和利用具有重要的现实意义。 相似文献
15.
A.T. Fuller 《Journal of The Franklin Institute》1974,297(1):7-16
For plants containing simple lags in certain ratios, and with saturable control input, the time-optimal control problem is reduced to the corresponding problem for a plant containing pure integrators. The method uses transformations of variables, and applies to systems of general order. Sub-optimal controllers for the plants with lags are also investigated by means of these transformations. 相似文献
16.
长白山区分布着国家级第一、二批珍稀濒危植物不仅在医药、花卉观赏、化工、木材等方面具有较高的开发利用价值，而且还具有生态保护和科学研究价值，近年来，由于自然，人为及社会综合因素的影响，使生态环境遭到严重破坏，许多珍稀有植物濒临灭绝。因此，积极、有效地保护与$长白山、珍稀濒危植物、保护、持续利 相似文献
17.
Joshua J. Skinner 《Journal of The Franklin Institute》1918,186(6):723-741
The experimental results show that aldehydes are harmful to plant growth in aqueous culture solutions, in nutrient solutions, in soil in pots, and in soil in the field.The effects of six aldehydes—namely, salicylic aldehyde, vanillin, benzaldehyde, heliotropine, formaldehyde, and paraformaldehyde—were studied in nutrient-culture solutions and each proved to be detrimental to plant growth.The effect of the compounds varied according to the composition of the nutrient solutions. Salicylic aldehyde was least harmful in solutions composed of a high percentage of phosphates. Vanillin was least harmful in solutions with a high percentage of nitrates. Benzaldehyde was about equally harmful in all the nutrient solutions. It was slightly more harmful, however, in the high nitrate solutions than in the mainly phosphatic or potassic cultures. Paraformaldehyde was also least harmful in the phosphate culture, but formaldehyde and heliotropine showed harmful effects to an equal degree in almost all cultures, regardless of their composition.Salicylic aldehyde and vanillin were found to occur in soils quite frequently, especially in soils of low productivity. The isolated substance from the soils was harmful to plants when dissolved in aqueous solution.The two aldehydes were harmful in some soils and not in others. The field studies show that the added aldehydes disappeared in some soils and not in others. There was no harmful action where the aldehydes were destroyed. The soils in which the aldehydes were destroyed have strong biological activities, good oxidation powers, and are fertile.The results of the experimental work presented in this paper further show that unfertile soils, where due to the presence of harmful aldehydes, can be made productive by good drainage and by the use of lime and certain fertilizers. This is demonstrated, first, by the growth of plants in nutrient solutions, where it is shown that phosphates partially overcome the bad effects of salicylic aldehyde, and that nitrates ameliorate the harmfulness of another aldehyde, vanillin. Second, by the more normal absorption of phosphates by plants growing in solutions containing salicylic aldehyde. Third, by the growth of plants in soil in pots, which shows that the harmful action of salicylic aldehyde is partially overcome by lime and phosphates and the effects of vanillin by lime and nitrate fertilizers. Fourth, by the growth of plants in field soils to which aldehydes were added, which again shows that lime and phosphates lessen the harmfulness of salicylic aldehyde and lime and nitrates alter the effects of vanillin. Fifth, by chemical tests in which it was shown that salicylic aldehyde, when added to a soil, was destroyed where lime and phosphates were added, and vanillin was destroyed where lime and nitrates were added. Sixth, by the improved productivity from the addition of lime and phosphates to a soil in which salicylic aldehyde was naturally formed and persisted for a period of years. 相似文献
18.
印度芥菜BjPCS1基因的表达提高烟草对重金属的抗性 总被引：4，自引：0，他引：4
在植物体内植物络合素(PC)可与重金属螯合,并进一步转运至液泡贮存,使细胞质的重金属浓度降低,从而达到解毒效果。PC不是基因的直接翻译产物,而是以谷胱甘肽(GSH) 为底物由植物络合素合酶催化而成。将来源于重金属超富集植物印度芥菜(Brassica juncea)的植物络合素合酶基因BjPCS1转入烟草,PCR和Northern结果表明,该基因已经整合到烟草基因组中,并在转录水平上表达。在3种重金属(200mmol/L CdCl2、400mmol/L ZnCl2、200mmo/L NiCl2)胁迫条件下,转基因烟草植株的脯氨酸含量、可溶性糖含量、丙二醛含量、相对电导率和叶绿素含量等指标均优于未转化的对照植株,表明转化BjPCS1基因提高了烟草对3种重金属的抗性,其中转基因烟草抗Cd能力最强,并且转基因烟草的T1代种子在Cd处理的情况下萌发状况明显优于对照。这些结果说明BjPCS1基因在利用基因工程改良植物抗重金属能力和净化环境污染方面,具有良好的应用前景。 相似文献
19.
我国中药资源基础研究的现状与热点 总被引：6，自引：0，他引：6
本文总结近5年（1999—2003年）国家自然科学基金资助中药资源基\\r
础研究的情况，并主要介绍植物遗传基因和生态环境影响药用成分的研究、植物次生代谢产\\r
物的生物合成调控研究、生物技术对中药材育种、评价和鉴定研究、太空环境对中药的遗传
效应及变异机理研究、转基因药用植物研究等方面的基础研究进展。 相似文献
20.
《Endeavour》1997,21(4):169-171
Keith R. Porter died on 2 May 1997. Although he was especially renowned for the work on cell structure recounted here, his impact on cell biology was not confined to the early electron-microscopic studies of ultrastructure. To many, he was the father of cell biology, who helped establish many of the enduring institutions and ideas in the field. He had great biological intuition and feeling for a wide range of organisms and was greatly concerned with problems of cell shape and movement. He used ultrastructure and simple physiological or biochemical experiments to infer functional activities for cell organelles, including not only the endoplasmic reticulum, which he named, but the sarcoplasmic reticulum and T-tubules of muscle cells, microtubules, cilia, coated vesicles and more. He also pioneered cell studies with the high-voltage electron microscope, which led him to the idea of structural integration in the cell cytoplasm, an idea that is only now being pursued with success. 相似文献