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The stem of Ipomoea batatas (L.) Lam. is characterized by thepossession of a ring of bicollateral, leaftrace bundles. Lacticifersoccur in the pith, in the parenchyma between neighbouring islandsof medullary phloem, and in the cortex. The xylem groups become united by the activity of the inter-fascicularcambium. The production of a certain amount of secondary xylemtakes place before the production of secondary phloem begins.The former is produced more extensively in some areas than inothers, so that the original symmetry of the vascular cylinderis lost. The phellogen originates in the cells of the epidermis. When the stem is attacked by the larvae of Megastes grandalisGuen., which remove most of the internal tissues, anomalousgrowth takes place as a result of the activity of accessorycambia, which develop in the primary cortex, the secondary phloem,and the phelloderm. Residual parenchyma of the pith and/or xylemundergoes hyperplasia to produce a callus tissue which linesthe cavity made by the larvae. 相似文献
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Deborah C. Vela Guilherme V. Silva Joao A.R. Assad Andre L.S. Sousa Stephanie Coulter Marlos R. Fernandes Emerson C. Perin James T. Willerson L. Maximilian Buja 《The journal of histochemistry and cytochemistry》2009,57(2):167-176
In this histological study, we assessed the role of mesenchymal stem cells (MSCs) in the healing process that takes place during the subacute phase of myocardial infarction in dogs. Seven days after occlusion of the left anterior descending coronary artery, adult mongrel dogs received 100 × 106 4′-6-diamidino-2-phenylindole (DAPI)-labeled allogenic bone marrow–derived MSCs by the transendocardial (TE, n=6) and intracoronary (IC, n=4) routes; control dogs (n=6) received no infusion. The dogs were euthanized at 21 days after occlusion. Hearts were excised and sliced from apex to base into four transverse sections, which were divided into nine segments. Paraffin sections from each segment were stained with hematoxylin and eosin, trichrome, picrosirius red, and antibodies against several extracellular matrix components. Frozen sections were immunostained for host cardiac phenotypical markers and analyzed by epifluorescence and deconvolution fluorescence microscopy (DFM). We found less unresolved necrotic myocardium and more extracellular matrix deposition in MSC-treated dogs than in controls 2 weeks after cell delivery. By DFM, no DAPI+ MSC nuclei were observed within native cardiac cells. MSCs delivered during the subacute phase of acute myocardial infarction positively affect healing, apparently by mechanisms other than differentiation into mature native cardiac cells. (J Histochem Cytochem 57:167–176, 2009) 相似文献
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A fossil wood from the Irrawady System of Burma (Pliocene toUpper Miocene) is described. Anatomically it is indistinguishablefrom the wood of living Terminalia tomentosa W. & A. anddiffers from all Terminalioxylon so far reported. The relationof this wood with the ring-porous and diffuse-porous woods isdiscussed. 相似文献
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The resin of the mango stem consists mainly of terpenes. Theterpenes seem to be produced primarily by plastids, termed heresecretoplasts. At the beginning of the process of secretion,osmiophilic droplets are seen at the envelope of the secretoplastsand at elemints of periplastidal ER. In addition, such dropletsoccur also at Golgi bodies and occasionally in association withmitochondria. Later osmiophilic material fills the well-developbdER, which at this stage is mainly tubular. It appears that theER is involved in the transport of the sareted material towardsthe plasmalemma. Mangifera indica L., mango, Anacardiaceae, resin, resin ducts, secretion, secretoplasts, ultrastructure 相似文献
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兴安百里香的扦插繁育试验研究 总被引:4,自引:0,他引:4
为寻求兴安百里香人工扦插繁育的适宜条件,研究了三种不同基质(校园土、细砂、珍珠岩)、两种处理(ABT生根粉溶液处理和不经处理)和三个生长期(15d,30d,40d)三因素对兴安百里香插穗的生根情况的影响。结果表明:不经生根液处理直接扦插的最佳基质为校园土;长时间(24h)ABT生根液(0.1g.L^-1)浸泡的插穗生根受到抑制,而经过0.g.L^-1ABT生根液浸渍5min插穗的校园土中在生根情况明显好于未经处理的插穗。扦插后15天的校园土中的生根率就已达到了85%,40天时达到100%。 相似文献
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We developed eight polymorphic microsatellite loci in Indian neem (Azadirachta indica var. indica) and cross-amplified in closely related species Thai neem (A. indica var. siamensis). The number of alleles per locus in Indian neem and Thai neem ranged from 3 to 9 and 3 to 9, respectively. Average observed
and expected heterozygosities in Indian neem and Thai neem were 0.63 and 0.70 and 0.61 and 0.65, respectively. Two loci exhibited
significantly fewer heterozygotes than expected under Hardy–Weinberg equilibrium. These microsatellites may provide a useful
tool for population genetics to establish conservation and management strategy. 相似文献
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Correlative Growth in Seedlings of Phaseolus vulgaris L. : Inhibition of Stem Growth by the Primary Leaves 总被引:1,自引:0,他引:1
Primary leaves of one-week-old seedlings of dwarf beans effectivelyinhibit stem elongation either in natural daylight or in continuousdarkness. Stem elongation is promoted by exogenous gibberellicacid and kinetin and inhibited by indol-3-ylacetic acid (IAA)or abscisic acid, and it is suggested that IAA is the inhibitorysubstance emanating from the primary leaf blades which affectsthe growth of the stem. 相似文献
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David N. Gellner 《American anthropologist》2003,105(2):434-435
Lord of the Dance: The Mani Rimdu Festival in Tibet and Nepal. Richard J. Kohn. Albany: State University of New York Press, 2001. 320 pp. 相似文献
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Frantiek Dvok 《Feddes Repertorium》1971,82(6):421-432
The paper investigates the generic classification of the species called Arabis glandulosa Kar. & Kir., Bull. Soc. Nat. Moscou, 15, 146 (1842). It classifies it in the tribe Hesperideae Prantl in Engler & Prantl, in the genus Alaida Dvořák gen. nov. related to the genus Dontostemon Andrz. in DC. The paper also substantiates the classification by quoting the results, achieved so far, of the investigation of the evolutional relationship in the tribe Hesperideae Prantl in Engler & Prantl. 相似文献
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The growth of fungi causing apple replant disease (ARD) was inhibited by the addition of N and P to the growing medium. The population of bacteria antagonistic to ARD-causing fungi was significantly increased in the growing medium supplemented with N 400 P 400 mg/l or greater. The application of nitrogen alone or in combination with phosphorus to soil infested with fungi or bacteria that cause apple replant disease significantly increased seedling height. The addition of P alone to these infested soils did not have any effect on seedling height. Significant increases in seedling height occurred with N applications when seedlings were grown in soil to which bacteria that are antagonistic to fungi causing ARD had been added. These results suggest that the application of N, with or without P, to apple replant soils may suppress the growth of ARD-causing fungi or bacteria and promote the growth of antagonistic bacteria. 相似文献
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利用瘤茎形状有较大差异的4个茎瘤芥(Brassica juncea var.tumida Tsen et Lee)自交系作为亲本配置了2个杂交组合,并以瘤茎形状指数作为度量指标,应用主基因+多基因混合遗传模型对其衍生后代家系群体P1、P2、F1、B1、B2和F2瘤茎形状进行了多世代联合遗传分析。杂交组合y203×b145的瘤茎形状受2对加性-显性-上位性主基因控制,其遗传率在B1、B2和F2群体中分别为59.89%、26.18%和54.14%;而瘤茎形状在杂交组合y92×b146中受2对加性-显性-上位性主基因+加性-显性多基因控制,在B1、B2和F2家系群体中,其主基因遗传率分别为22.44%、58.06%和63.14%,多基因遗传率分别为40.42%、4.36%和1.26%。这些结果表明,对瘤茎形状改良时要以主基因利用为主,且宜在中高世代选择。 相似文献
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Ana I. Gon?alves Márcia T. Rodrigues Sang-Jin Lee Anthony Atala James J. Yoo Rui L. Reis Manuela E. Gomes 《PloS one》2013,8(12)
Current treatments for tendon injuries often fail to fully restore joint biomechanics leading to the recurrence of symptoms, and thus resulting in a significant health problem with a relevant social impact worldwide. Cell-based approaches involving the use of stem cells might enable tailoring a successful tendon regeneration outcome. As growth factors (GFs) powerfully regulate the cell biological response, their exogenous addition can further stimulate stem cells into the tenogenic lineage, which might eventually depend on stem cells source. In the present study we investigate the tenogenic differentiation potential of human- amniotic fluid stem cells (hAFSCs) and adipose-derived stem cells (hASCs) with several GFs associated to tendon development and healing; namely, EGF, bFGF, PDGF-BB and TGF-β1. Stem cells response to biochemical stimuli was studied by screening of tendon-related genes (collagen type I, III, decorin, tenascin C and scleraxis) and proteins found in tendon extracellular matrix (ECM) (Collagen I, III, and Tenascin C). Despite the fact that GFs did not seem to influence the synthesis of tendon ECM proteins, EGF and bFGF influenced the expression of tendon-related genes in hAFSCs, while EGF and PDGF-BB stimulated the genetic expression in hASCs. Overall results on cellular alignment morphology, immunolocalization and PCR analysis indicated that both stem cell source can be biochemically induced towards tenogenic commitment, validating the potential of hASCs and hAFSCs for tendon regeneration strategies. 相似文献
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研究了4种低聚糖、8种中药及4种食品原料体外对双歧杆菌菌株A04的增殖作用。结果表明,大豆低聚糖的增殖效果最明显(P〈0.01),其次是低聚异麦芽糖和低聚果糖,水苏糖则几乎没有增殖效果,而且当改良MRS中低聚糖的浓度达到10%时,对其反而具有一定的抑制作用;8种中药在浓度为2%的时均有增殖效果,以Z3、Z1和Z2效果最显著(P〈0.01),但其浓度不同对双歧杆菌菌株A04的增殖影响截然不同;本试验采用的4种食品原料对双歧杆菌均有促生长作用,较好的增殖作用的组合分别为:M-5%,CJ-2%,TE-2%和LE-5%。 相似文献