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9种榆科植物叶表皮结构特征研究 总被引:2,自引:0,他引:2
利用叶表皮离析法观察了榆科6属9种植物叶片的表皮结构。结果表明,榆科植物叶片气孔器仅分布在远轴面,不规则型,不具副卫细胞;叶片毛状体主要有腺毛和非腺毛两种类型,腺毛由基细胞、柄细胞和膨大的顶细胞构成,非腺毛均由单细胞发育而来,基部具或不具钟乳体,多数非腺毛顶部发育成长锥状,少数非腺毛顶部极短呈喙状。根据气孔器的类型和分布位置,尤其是表皮毛的基本结构和发育类型等特征,不支持将广义榆科分为两个独立科的观点。但榆科这9种植物叶表皮特征具有属间或种间差异,有一定的分类学价值。 相似文献
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结球甘兰下胚轴组织培养形态发生的组织学研究 总被引:7,自引:0,他引:7
结球甘兰离体下胚轴培养,近切口的中柱薄壁细胞首先启动分生,中柱外的内皮层,皮层,表皮细胞随后也启动分生。随着愈伤组织的生长和愈伤形成层的建成,维管组织与分生组织产生。组织培养中出现的多倍性细胞团和单倍性细胞,不会引起原二倍体物种的遗传性变异和性状变化。在愈伤组织中,芽多为外起源。由原体原始细胞和原套原始细胞发育成芽原基,进一步形成不定芽。另外,不定芽还可由外植体皮层内薄壁组织直接产生。不定根为内起 相似文献
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本文研究了芡个体发育的早期,即心形胚至种苗。心形胚至成熟胚表现为:苗端先发育,根端弱育;胚芽叶节上的节生根原基先发育,端无明显分化。种子胚至种苗表现为:种子萌发时,下胚轴末端产生多细胞分枝下胚轴毛;种苗形成中,节生根先发育,胚后发育,且长达1mm左右即停止生长这些器官发育顺序上的特点在被子植物中是很特殊的,应该是系统发生上的原始性状,下胚轴毛是水生或显生被子植物比较普遍的性状,是区分下胚轴与胚奶的指示性状。 相似文献
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采用透射电子显微镜观察经10℃低温处理2d的豌豆下胚轴细胞超微结构的结果显示,10℃低温处理后,豌豆下胚轴细胞超微结构未受到显著伤害,但其一些抵御寒冷的适应性能力有变化。质膜呈波浪状,或质壁分离,或凹陷、外凸形成小泡;中央大液泡和细胞质内、以及内质网和高尔基体附近多处出现泡状结构或小泡;多数质体变形为哑铃形、变形虫形、马蹄形、镰刀形和棒状等,其中的淀粉粒显著减少。 相似文献
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余迪求 《发育与生殖生物学报》1995,4(2):30-38,T001
本文发展的技术可以使金鱼草下胚轴外植体不定芽高频再生。添加有2mg/l BAP和0.5mg/l NAA的MS培养基上再生芽出得又快又多,淡黄色愈伤组织易于形成并存活,但主要依赖的是6-BAP。MS培养基中含有0.1mg/l和6mg/l浓度的6-BP均能刺激芽的发育,最适浓度为2-3mg/l。仅加2.4-D,也能形成正常的黄色愈伤组织,但这样形成的愈伤组织在只含有0.1-6mg/l6-BAP或含有2mg/l6-BAP和0.5mg/lNAA的MS培养基上均不能分化生出再生芽来。仅加NAA,能够刺激下胚轴形成根。加入AgNO3,则抑制不定芽的再生,并导致整个外体变成棕色而死亡。组织化学分析结果表明:不定芽的再生源于下胚轴外植体表皮细胞。在不含有任何生长调节的MS培养基上,再生苗均能形成根。再生植株移栽至花盆可开花结实。 相似文献
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Stylianos Delivopoulos 《欧洲藻类学杂志》2013,48(3):329-338
The apex of the tetrasporangial branches of Osmundea spectabilis var. spectabilis (= Laurencia spectabilis var. spectabilis) exhibits cavities in which tufts of multicellular trichoblasts occur. Trichoblast development in Osmundea spectabilis var. spectabilis begins with the differentiation of an epidermal cell within the crypt. This cell differentiates into a trichoblast mother cell (TMC). The TMC divides to form a two-celled incipient trichoblast. Successive periclinal divisions of the apical cell of the young trichoblast result in the formation of a multicellular developing trichoblast. With the exception of the apical cell all trichoblast cells are at the same developmental stage. They possess a large nucleus, abundant plastids with peripheral and some internal thylakoids and dictyosomes. Daughter chloroplasts result from one constriction or multiple fission of a single chloroplast. Dictyosomal cisternae and mucilage sacs contribute material to wall formation. Each differentiating trichoblast cell is surrounded by a bi-layered wall. The outer wall layer represents the trichoblast mother cell wall and the inner wall layer is the trichoblast cell wall. Mature trichoblast cells have thin walls, probably as a consequence of mucilage extrusion, the most likely function of trichoblasts in Osmundea. 相似文献
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Ultrastructure was investigated along the files of developing epidermal cells in the root tip of a model plant Medicago sativa, in which all rhizodermal cells are potential hair-forming trichoblasts. Differentiation at subcellular level was observed
up to the stage of bulge initiation in the trichoblasts. Root hair initiation indicated by the emergence of bulges from trichoblasts
was detected at various distances from the root tip and, it was independent of the trichoblast size.
During rhizodermal cell differentiation, starch grains accumulated in the plastids. Nuclei located in the central part of
the young, meristematic cells moved towards the inner periclinal wall as the central vacuole enlarged. The bulging region
of the trichoblasts located opposite the nucleus and was rich in mitochondria, ER, ribosomes, and Golgi bodies, and contained
also vesicles enclosing fibrillar material. This material responded positively to phosphotungstic acid, which was used for
detection of cell wall polysaccharides. The cell wall thickness within the bulging domain was significantly lower than in
other parts of trichoblasts. We suggest that internalization of cell wall polysaccharides occurs within the bulging area,
contributing to local thinning of the cell wall and providing a source of osmotically active compounds for maintaining turgor
in the trichoblast. Thus, the internalization process might be necessary for root hair outgrowth. 相似文献
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玉吊钟气生不定根根尖区域的部分表皮细胞经分裂可形成多细胞根毛。根毛长0.03mm左右,具单列细胞、双列细胞和叉状分枝类型,由基细胞和毛体细胞二部分组成。电镜显示,基细胞内部结构与表皮细胞相似。组成毛体的细胞都有分泌功能。在分泌活动期,细胞内形成大量内质网,并膨大成囊泡状或溢出囊泡,分泌停止,内质网即消失;其细胞结构的变化及主要由内质网参与分泌活动与蜜腺细胞在分泌活动中的结构变化类似。故推测多细胞根 相似文献
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Root Hair Development 总被引:6,自引:0,他引:6
Root hairs are projections from the epidermal cells of the root that are thought to increase its effective surface area for nutrient and water uptake, enlarge the volume of exploited soil, and aid in anchoring the plant to the soil. Their formation occurs as a series of developmental processes starting with cell fate specification in the meristem. The root-hair-forming epidermal cell, or trichoblast, then participates in the diffuse growth phase associated with the elongation of the main root axis. After the fully elongated trichoblast exits the elongation zone, growth is reorganized and localized to the side in the process of root hair initiation. Initiation is then followed by a sustained phase of tip growth until the hair reaches its mature length. Thus, root hairs provide insight into a range of developmental processes from cell fate determination to growth control. The theme emerging from the molecular analysis of the control of root hair formation is that many regulators act at several stages of development. Root hair formation is also responsive to a multitude of nutrient and other environmental stimuli. Therefore, one explanation for the presence of the complex networks that regulate root hair morphogenesis may lie in the need to coordinate their highly plastic developmental program and entrain it to the current soil microenvironment being explored by the root. 相似文献
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Root hairs are projections from the epidermal cells of the root that are thought to increase its effective surface area for nutrient and water uptake, enlarge the volume of exploited soil, and aid in anchoring the plant to the soil. Their formation occurs as a series of developmental processes starting with cell fate specification in the meristem. The root-hair-forming epidermal cell, or trichoblast, then participates in the diffuse growth phase associated with the elongation of the main root axis. After the fully elongated trichoblast exits the elongation zone, growth is reorganized and localized to the side in the process of root hair initiation. Initiation is then followed by a sustained phase of tip growth until the hair reaches its mature length. Thus, root hairs provide insight into a range of developmental processes from cell fate determination to growth control. The theme emerging from the molecular analysis of the control of root hair formation is that many regulators act at several stages of development. Root hair formation is also responsive to a multitude of nutrient and other environmental stimuli. Therefore, one explanation for the presence of the complex networks that regulate root hair morphogenesis may lie in the need to coordinate their highly plastic developmental program and entrain it to the current soil microenvironment being explored by the root. 相似文献
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H.T.H.M. Meekes 《Aquatic Botany》1985,21(4):347-362
Trichoblasts and root hairs of Ceratopteris thalictroides (L.) Brongn. were studied by different techniques to survey their morphological features. Trichoblasts could be identified at an early stage by an intra-vacuolar precipitate appearing during fixation. Special attention was paid to root-hair initiation. No structures or changes were observed that play a role in the initiation of papilla formation. When the papilla is formed, vesicles and periplasmic membranes can be observed which may play a role in the weakening of the cell wall during the papilla outgrowth.During root-hair growth, the nucleus of the trichoblast moves from the trichoblast to a subapical position in the root hair. The nuclei of all root cells contain 2 types of nuclear inclusions, one of which is proteinaceous.The cell wall of the Ceratopteris root hair has a helicoidal texture and because the cortical microtubules run longitudinally in the root hair, no correlation can be made between the directions of microtubules and microfibrils in these root hairs. 相似文献
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利用光学显微镜、扫描电镜和透射电镜技术,观察了龙葵“四叶一心”期时叶片及茎表皮的腺毛的种类、分布,探究了不同类型腺毛的起源、生长、成熟、分泌、衰老等发育过程的细胞学特征;通过组织化学染色和荧光显微技术,观察了龙葵腺毛成分、分布,为龙葵的进一步开发利用提供参考。结果表明:(1)龙葵腺毛分为单细胞头腺毛和多细胞头腺毛两类,前者主要分布于茎表面和叶上下表皮,后者主要分布于茎表面的单细胞头腺毛之间、叶脉及叶边缘;(2)龙葵腺毛发育起始于表皮细胞突起,单细胞头腺毛行顶端生长,具1-4个柄细胞,四种类型;多细胞头腺毛可再分为一层、两层与三层多细胞头腺毛,另具三种特殊类型;(3)龙葵成熟腺毛具分泌能力,通过皮下空间的物质积累导致腺毛头细胞表面形成突起、包块、破口,最终释放分泌物;而头细胞与柄细胞随即皱缩、衰老。(4)超微结构显示,腺毛头细胞中内质网与高尔基体极为丰富,合成代谢及分泌活动活跃,产生大量包裹嗜锇物质的囊泡,囊泡与细胞壁融合,进而将嗜锇物质转移至细胞壁并积累,随后储存在角质层下的皮下空间直至分泌释放;(5)组织化学染色结果表明,腺毛含有萜类、生物碱、脂类、蛋白质、酚类和多糖。头细胞中主要含有萜类、生物碱、脂类、蛋白质、酚类和中性多糖;柄细胞中主要含有萜类、生物碱、脂类。 相似文献
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Root hairs are an excellent model system to study cell developmental processes as they are easily accessible, single-celled, long tubular extensions of root epidermal cells. In a genetic approach to identify loci important for root hair development, we have isolated eight der (deformed root hairs) mutants from an ethylmethanesulfonate (EMS)-mutagenized Arabidopsis population. The der lines represent five new loci involved in root hair development and show a variety of abnormalities in root hair morphology, indicating that different root hair developmental stages are affected. A double mutant analysis with the short root hair actin2 mutant der1-2 confirmed that the der mutants are disturbed at different time points of root hair formation. Auxin and ethylene are known to be important for trichoblast cell fate determination and root hair elongation. Here, we show that they are able to suppress the phenotype of two der mutants. As the auxin- and ethylene-responsive der mutants are affected at different stages of root hair formation, our results demonstrate that the function of auxin and ethylene is not limited to cell differentiation and root hair elongation but that the two hormones are effective throughout the whole root hair developmental process. 相似文献
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Root Hairs as a Model System for Studying Plant Cell Growth 总被引:5,自引:0,他引:5
Root hairs are tip-growing projections that form on specializedepidermal cells. Physiological studies are identifying key transportersrequired for hair growth, and drug studies have been instructivein defining the role of the cytoskeleton in cell morphogenesis.Genetic analysis is identifying proteins involved in cell growthand the phenotypes of the mutants are instructive in definingthe precise function of these proteins in cellular morphogenesis.Recent progress in our understandings of cell growth using thearabidopsis root hair as a model system is reviewed. Copyright2001 Annals of Botany Company Arabidopsis, root hair, trichoblast, actin, microtubules, cell wall, genetics, calcium, potassium, phosphorus 相似文献