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1.
B chromosomes: a physiological enigma   总被引:3,自引:0,他引:3  
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青海赖草属一新种和一新变种   总被引:8,自引:1,他引:7  
1 青海赖草 新种 图1:1~9LeymusqinghaicusL.B.Cai,sp.nov.Fig.1:1~9HaecspeciesL.secalino(Georgi)Tzvel.proxima,aquodiffertspicisbrevibus,6~10cmlongis,brunneisvelbrunneolis,glumisangustelanceolatis,saepe1nervibus,inutroquelatereleviterasymmetricis,paleislemmatibusevidenterbrevi…  相似文献   

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半乳甘露聚糖植物胶加工是我国70年代中期兴起的新兴产业。本文从我国植物资源发展的角度。重点论证了瓜尔豆(Cyanopsis tetragonoloba(L.)Taubert.)、田菁(Sesbania cannabina(Retz.)Pers.)、胡芦巴(Trigonella foenum-graecum L.)的生产情况,认为胡芦巴适应性强、产量高、易于机械化大面积种植与轮作,并具有改良土壤以及经济效益好等优势。因此,发展半乳甘露聚糖胶资源,大量种植胡芦巴是最好的选择。  相似文献   

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Chloroplast DNA from three barley cultivars and from one lettuce cultivar was prepared from chloroplasts isolated by Conventional differential centrifugation. Barley chloroplast DNA size was sensibly lower (130 kpb) than lettuce chloroplast DNA (150 kpb). Chloroplast DNAs from the three barley cultivars showed similar restriction fragment patterns after digestion with: BamHI, EcoRI or HindIII. The lettuce chloroplast DNA restriction pattern was very different from the barley chloroplast DNA restriction pattern.  相似文献   

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Abstract The role of chlorophyll in the mature embryos of several tropical plants (Phthirusa pyrifolia [H.B.K.] Eichl. [Loranthaceae]. Murraya koenigia Kurz. [Rutaceae], Murraya paniculata Jack. [Rutaceae], Syzygium cuminii [L.] Skeels [Myrtaceae]) was investigated. Extracted chloroembryos of all species do photosynthesize when illuminated. Whole mature fruits of M. koeningii, M. paniculata and Syzygium cuminii exhibited some photosynthetic activity, but pericarps of none of the fruits photosynthesized when exposed to light. Thus the photosynthetic activity of fruits may be ascribed to CO2 uptake by chloroembryos embedded in the fruits. A specific aspect of plant physiology, namely the re-utilization of respired CO2 in the process of photosynthesis is emphasized. It is postulated that within embedded chloroembryos, conditions such as high CO2 concentration, high light intensity, and low oxygen concentration are favourable for conducting intensive photosynthesis. Photosynthesis within enclosed organs has an additional advantage in that is does not expose the plant to any risk of water loss usually associated with photosynthesis.  相似文献   

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α and β chains of hemoglobin have been modified with cobalt(II) tetrasulfonated phthalocyanine in place of heme. They display properties very similar to those of iron(II) phthalocyanine modified α and β chains. Mixed together they form tetrameric cobalt(II) phthalocyanine hemoglobin.Incorporation of Co(II)L into α and β globins results in stabilization of the protein structure, which is shown by a marked increase in its helicity content. Cobalt phthalocyanine substituted α and β chains are able to combine reversibly with oxygen giving more stable oxygenated species than their native analogues. The rate of both processes is lower in the case of the modified α chain. Recombination of the phthalocyanine α and β chains with the alternate heme containing chains give tetrameric hybrid hemoglobins. These comprise two phthalocyanine modified subunits and two heme containing subunits. The helicity content of the tetrameric hybrid hemoglobin calculated for one subunit is lower that the arithmetic mean of helicities for its isolated subunits. This suggests a destabilizing chain-chain interaction within the tetramer. Unlike in the separated subunits, oxygen binding by hybrid hemoglobins is irreversible. Deoxygenation by argon bubbling leads to the formation of inactive species which in oxygen atmosphere undergo irreversible oxidation with destruction of the complex.  相似文献   

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卵唇山姜 新种 图版ⅠAlpiniaovataZ .L .ZhaoetL .S .Xu ,sp .nov .PlateⅠAbAlpiniastachyoidiHancediffertbracteolisoblongisetlabellisovatis.Herba ,1 .3~ 1 .5malta.Foliaelliptico lanceolata ,31~ 37cmlonga,3.5~ 7.5cmlata ,apiceacuminata,basiangustata ,utrinqueglabra ,marginedensetomentosa,n…  相似文献   

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Swards of Dactylis glomerata cultivars (cvs) KM2 and Lutetia and of Lolium perenne cvs Aurora and Vigor were grown under full irrigation or prolonged summer drought (80 d) in a field experiment in the South of France.
After irrigation was withheld, leaf extension rates of all cvs fell by 90% within 9–12 d, and rapid scorching of laminae followed. Tiller mortality at the end of the drought was very different in the cocksfoot cvs (4% for KM2 and 76% for Lutetia) and intermediate (41%) for both ryegrass cvs. Following re-watering, rates of herbage regrowth were closely correlated with tiller survival. Measured minerals contributed c . 0·52 MPa to osmotic potential in all treatments, whereas water-soluble carbohydrates (WSC) contributed 0·25 MPa under irrigation and 0·46 MPa during drought.
There was no systematic difference between the two species for summer survival under severe drought, but large differences between the cocksfoot cvs. The traits most strongly associated with superior survival were: (a) a deep root system and greater water uptake at depth; (b) low water and osmotic potentials in surviving laminae, i.e. better tolerance to dehydration; (c) large pool-size of WSC reserves (fructans having degree of polymerization >4) in entire tiller bases (stubble); (d) low accumulation of proline in stubble; (e) rapid nitrogen uptake after rewatering.  相似文献   

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以广东连州自然分布的3种国家重点保护野生植物南方红豆杉〔Taxus chinensis var.mairei(Lemée et Lévl.)Cheng et L.K.Fu〕、半枫荷(Semiliquidambar cathayensis Chang)和金荞麦〔Fagopyrum dibotrys(D.Don)Hara〕为研究对象,分析了根、茎和叶片及根际土壤和岩石的C、N含量和C:N比以及δ13 C和δ15 N值的差异;在此基础上,通过δ13 C和δ15 N值的散点图比较了3种植物生态位的差异.结果表明:在同种植物中,根、茎和叶片的C和N含量及C:N比总体高于根际土壤和岩石,其中,叶片中C和N含量均最高,茎的C:N比最高;而根际土壤和岩石的δ13 C和δ15 N值总体高于根、茎和叶片.在供试的3种植物间,根际土壤和岩石中C和N含量总体上无明显差异,但根、茎和叶片中C和N含量以及根、茎和叶片及根际土壤和岩石的C:N比、δ13 C和δ15 N值均有一定差异;其中,金荞麦根中C含量显著(P<0.05)低于南方红豆杉和半枫荷,其根、茎和叶片中N含量和δ15 N值均极显著(P<0.01)高于后二者,其根、茎和叶片的C:N比和δ13 C值均极显著低于后二者,其根际土壤和岩石的C:N比和δ13 C值总体上也低于后二者;南方红豆杉和半枫荷的叶片中C和N含量以及茎和叶片的δ13 C值、根际土壤和岩石的δ13 C和δ15 N值均存在显著差异,但二者的整体差异相对较小.从散点图上看,金荞麦的生态位远离南方红豆杉和半枫荷,而后二者的生态位有交集.综合分析结果显示:草本植物金荞麦与木本植物南方红豆杉和半枫荷的C和N含量以及δ13 C和δ15 N值的差异不仅与植物自身的生活型有关,而且与各自生境中的光照和土壤因子等相关.另外,供试3种植物的根、茎和叶片的δ13 C值变幅为-31.69‰~-26.46‰,符合C3植物的δ13 C值范畴.  相似文献   

13.
红凤菜和白子菜总黄酮含量的动态变化   总被引:1,自引:0,他引:1  
红凤菜[Gynura bicolor (Willd. ) DC. ]和白子菜[G. divaricata (L. ) DC. ]均为菊三七属(Gynura Cass. )植物~([1]).红凤菜的嫩茎叶中含有丰富的营养成分,可作蔬菜食用~([2]);白子菜叶片在民间用于治疗糖尿病,动物实验证明其有显著的降血糖作用~([3]).  相似文献   

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中国芦荟染色体核型分析   总被引:8,自引:1,他引:7  
以中国芦荟为试验材料,按常规染色体压片法,观察中期分裂相并进行显微摄影。染色体类型按Levan方法分类,其核型为K(2n)=6st+8sm。  相似文献   

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百合科(Liliaceae)天门冬属(Asparagus (Tourn.)L.)植物具有悠久的药用历史,如天门冬(A.cochinchinesis (Lour) Merr.)早在汉代《神农本草经》中就被列为上品,具有滋阴、润燥、降火、止咳等功效。现代药理研究及临  相似文献   

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粗山羊草(Aegilops tauschii(Coss.)Schmal.,DD,2n=14)是普通小麦(Triticumaestivum L.,AABBDD,2n=42)D染色体组的供体。粗山羊草中含有丰富的抗病,抗虫,抗逆,优质等优异基因,因此粗山羊草是改良普通小麦的宝贵遗传资源。但有关普通小麦与粗山羊草杂交的研究报道较少。本文试图通过对普通小麦与粗山羊草杂种后代的细胞遗传学和染色体分离规律的研究,探讨转移粗山羊草优异基因的方法和途径。  相似文献   

18.
Seasonal net carbon dioxide exchange of a beech forest with the atmosphere   总被引:10,自引:0,他引:10  
The seasonal carbon dioxide exchange of a beech forest of Central Italy was studied by means of the eddy covariance technique. Additional measurements of biomass respiration with cuvettes and relationship of carbon dioxide exchanges with temperature and light were used to interpolate missing data during the dormant and part of the growing season. The net ecosystem production of the forest equals 472 g C m?2 y?1 while the gross ecosystem production 1016 g C m?2 y?1 and respiration 544 g C m?2 y?1. These estimates are compared with the net primary production determined by direct biomass sampling which amounts to 802 g C m?2 y?1.  相似文献   

19.
A new experimental system was developed for studying the hormonal mechanisms which control tracheid differentiation. In this system the tracheids redifferentiated from parenchyma cells in the hypocotyl of young Pinus pinea L. seedlings. The experimentally induced tracheids have unique shapes and patterns, and are therefore easily distinguished from the primary and secondary tracheids formed before the experiments. Auxin (0·1–1% NAA) alone sufficed to cause the redifferentiation of short tracheids, usually in discontinuous patterns across the hypocotyl. Gibberellin by itself did not induce redifferentiated tracheids. Combinations of auxin with gibberellin (0·1% NAA+0·1–1% GA3) promoted the differentiation of long tracheids (up to threefold greater than those induced by auxin) in continuous patterns along the stem axis. Gibberellin in the presence of auxin promoted tracheid elongation by stimulating intrusive growth of both the upper and lower ends of the differentiating tracheids. The role of auxin and gibberellin in controlling the evolution of tracheary elements, from tracheids to vessels and fibres, is discussed.  相似文献   

20.
Antibody production to dinitrophenyl-keyhole limpet haemocyanin (DNP-KLH) served as the immune parameter to divergently select carp (Cyprinus carpio L.) to produce high- and low-responder F, hybrid lines. Antibody production to trinitrophenyl-lipopolysaccharide [TNP-LPS) and to DNP-KLH were similar in magnitude. By contrast, some high-responder lines were low responders to DNP-human serum albumin, and vice versa. Low-responder carp were relatively susceptible to infection with the parasite Trypanoplasma borreli. This suggested that at least one gene with a major influence on resistance differed between the two homozygous parents (69, 85) used to generate the high- and low-responder homozygous families, respectively. The isogenic lines showed no within-line variation in DNA fingerprints, but differed with respect to their MhcCyca-DAB genes.  相似文献   

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