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1.
荔枝雌蕊发育过程中钙分布变化与细胞程序性死亡 总被引:1,自引:0,他引:1
应用焦锑酸钾沉淀法研究了荔枝雌花和雄花雌蕊发育过程中钙的分布变化。在大孢子母细胞阶段,雌花近珠孔内珠被细胞和花柱细胞的钙沉淀颗粒主要分布在细胞壁和细胞间隙,少部分在液泡;雌花花柱维管细胞中含有很多的钙沉淀颗粒;在雄花的近珠孔内珠被细胞钙沉淀颗粒大多在液泡中;雄花花柱细胞和维管细胞中钙沉淀颗粒很少。大孢子母细胞减数分裂后,雌花雌蕊继续发育,雄花雌蕊败育。雌花维管中的钙沉淀颗粒数量减少,可能被转运到将要发生花粉萌发和受精的部位。雌花近珠孔内珠被细胞壁的钙沉淀颗粒分布增加,花柱细胞从上(近柱头)到下(近子房)钙沉淀颗粒量递增。雄花近珠孔内珠被细胞发生程序性死亡:液泡中的钙进入细胞核启动细胞程序性死亡,核周隙与质膜腔形成连续的通道,钙在核与细胞质之间的流动不受限制;在特定的时间段,钙沉淀颗粒出现在线粒体、过氧化物体和线型内质网的外膜上。钙在细胞中重新分布可能触发和调节细胞程序性死亡的进程。缺乏钙沉淀颗粒的雄花花柱细胞迅速解体。 相似文献
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用透射电镜研究了红豆草(Onobrychis viciifolia)根瘤侵染细胞中液泡内含物的超微结构特征。结果表明,早期发育侵染细胞的液泡中只含有少量的纤维状物质。随着细胞的发育,液泡不断变大,液泡中的纤维状物质和膜状物质越来越多。在中央液泡形成后,液泡中的纤维状物质逐渐减少,类细胞质、泡状和膜状物质明显增多,它们常由一层来自液泡膜的膜包围,其形状一般近似圆形或椭圆形。液泡内含物的大量出现可能与红豆草及其根瘤具有高度的抗旱件有关。 相似文献
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低温胁迫下董棕(Garyota urens L.)幼苗叶肉细胞内Ca^2+水平及细胞超微结构的变化 总被引:7,自引:0,他引:7
用焦锑酸钙沉淀的电镜细胞化学方法,研究了低温胁迫下董棕(Caryota urens L.)幼苗叶肉细胞内Ca^2 水平的变化。研究结果表明,未经低温处理的董棕幼苗叶肉细胞,焦锑酸钙沉淀颗粒大量出现在液泡和细胞间隙中,细胞壁中也可见少量沉淀,而细胞基质中则看不到焦锑酸钙沉淀;经2℃ 48h低温处理后,细胞基质和细胞膜上焦锑酸钙沉淀增加,而液泡和细胞间隙中的焦锑酸钙沉淀则显著减少,并且超微结构已初步显示出寒害的特征,叶绿体外膜部分破损,类囊体片层稀疏且排列不规则,光合速率明显下降等;经2℃ 120h低温处理后,细胞间隙内的焦锑酸钙沉淀极少,有的也紧贴在细胞外壁上,而细胞基质和细胞膜上则分布有非常多的焦锑酸钙沉淀,在核基质和液泡中也可见到少量的焦锑酸钙沉淀,并且超微结构遭到了显著破坏,叶绿体结构完全被破坏,核膜与液泡膜严重破损,内部结构模糊,细胞只表现为呼吸作用,不进行光合作用。表明Ca^2 的区域性分布的变化与植物抗寒性存在一定关系。 相似文献
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四季海棠成熟胚珠的组织化学及超微结构的初步研究 总被引:1,自引:0,他引:1
应用四季海棠的胚珠,进行石蜡切片,做PAS反应、苯胺兰黑染色等组织化学染色;又做超薄切片,进行超微结构观察。PAS反应:胚囊内染色深,珠被浅,各处均有红色淀粉粒。苯胺兰黑染色;显示胚囊内蛋白质丰富,卵核质兰色,核仁深兰,反足细胞更深。在超微结构中:珠被细胞中见到细胞核、线粒体、质体、内质网、同心圆潴泡、液泡等,近珠孔处珠被细胞内线粒体较多。珠心细胞内可见微管及其它细胞器。胚囊内助细胞可见丝状器。见到卵核、极核、线粒体、内质网、液泡、质体(其中未见淀粉粒)等。 相似文献
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低温逆境中黄瓜幼苗细胞内钙离子水平变化的细胞化学研究 总被引:6,自引:0,他引:6
采用改进的焦锑酸钙沉淀的细胞化学方法,探讨了Ca^2+在黄瓜幼苗细胞中超微结构定位分布及在低温逆境条件下Ca^2+水平的动态。结果表明:在适宜温度下生长的黄瓜幼苗,其细胞中Ca^2+主要定位于液泡及细胞间隙内,说明液泡是植物细胞内的主要钙库,并显示质外体中存在大量的Ca^2+分布。当黄瓜幼苗在1℃下冷胁迫28h后,质膜内侧钙沉淀颗粒明显增加,同时观察到液泡内Ca^2+分布变得比较集中,并趋向于液泡 相似文献
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低温胁迫下董棕(Garyota urens L.)幼苗叶肉细胞内Ca~(2+)水平及细胞超微结构的变化 总被引:4,自引:0,他引:4
用焦锑酸钙沉淀的电镜细胞化学方法 ,研究了低温胁迫下董棕 (GaryotaurensL .)幼苗叶肉细胞内Ca2 + 水平的变化。研究结果表明 ,未经低温处理的董棕幼苗叶肉细胞 ,焦锑酸钙沉淀颗粒大量出现在液泡和细胞间隙中 ,细胞壁中也可见少量沉淀 ,而细胞基质中则看不到焦锑酸钙沉淀 ;经 2℃ 48h低温处理后 ,细胞基质和细胞膜上焦锑酸钙沉淀增加 ,而液泡和细胞间隙中的焦锑酸钙沉淀则显著减少 ,并且超微结构已初步显示出寒害的特征 ,叶绿体外膜部分破损 ,类囊体片层稀疏且排列不规则 ,光合速率明显下降等 ;经 2℃ 1 2 0h低温处理后 ,细胞间隙内的焦锑酸钙沉淀极少 ,有的也紧贴在细胞外壁上 ,而细胞基质和细胞膜上则分布有非常多的焦锑酸钙沉淀 ,在核基质和液泡中也可见到少量的焦锑酸钙沉淀 ,并且超微结构遭到了显著破坏 ,叶绿体结构完全被破坏 ,核膜与液泡膜严重破损 ,内部结构模糊 ,细胞只表现为呼吸作用 ,不进行光合作用。表明Ca2 + 的区域性分布的变化与植物抗寒性存在一定关系。 相似文献
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用焦锑酸钙沉淀的电镜细胞化学方法,研究了低温胁迫下董棕(Garyota urensL.) 幼苗叶肉细胞内Ca2+水平的变化。研究结果表明,未经低温处理的董棕幼苗叶肉细胞,焦锑 酸钙沉淀颗粒大量出现在液泡和细胞间隙中,细胞壁中也可见少量沉淀,而细胞基质中则看 不到焦锑酸钙沉淀;经2 ℃ 48 h低温处理后,细胞基质和细胞膜上焦锑酸钙沉淀增加,而液泡和细胞间隙中的焦锑酸钙沉淀则显著减少,并且超微结构已初步显示出寒害的特征,叶绿体外膜部分破损,类囊体片层稀疏且排列不规则,光合速率明显下降等;经2℃ 120 h低温处理后,细胞间隙内的焦锑酸钙沉淀极少,有的也紧贴在细胞外壁上,而细胞基质和细胞膜上则分布有非常多的焦锑酸钙沉淀,在核基质和液泡中也可见到少量的焦锑酸钙沉淀,并且超微结构遭到了显著破坏,叶绿体结构完全被破坏,核膜与液泡膜严重破损,内部结构模糊,细胞只表现为呼吸作用,不进行光合作用。表明Ca2+的区域性分布的变化与植物抗寒性存在一定关系。 相似文献
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五唇兰雌配子体发育和胚胎发生的研究 总被引:13,自引:2,他引:11
五唇兰的胚珠倒生型,具薄珠心,两层珠被。胚囊发育为双孢子葱型,成熟胚囊8核。从传粉到受精约50d,正常双受精。胚具5-6细胞的胚柄,种子成熟时胚柄及胚乳核消失,成熟种子只具单层细胞的种皮和一个未分化的珠珠形胚。 相似文献
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五唇兰(DoritispulcherrimaLindl.)的胚珠属于倒生型,具薄珠心,两层珠被。胚囊发育类型为双孢子葱型,授粉后约45d形成七细胞八核的成熟胚囊。五唇兰未受精胚珠在离体培养初期对外源激素的依赖性很小,在没有外源激素的培养基上,大孢子母细胞也能经过减数分裂发育为二核胚囊。在培养后期,外源激素对胚囊发育的影响很大。在培养基无外源激素或仅含生长素或细胞分裂素时,雌配子体的发生过程不能顺利完成;在改良VW培养基上添加0.5mg/LBA和0.1mg/LNAA时,形成成熟胚囊。 相似文献
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Rice caryopsis as one of the most important food sources for humans has a complex structure that is composed of maternal tissues including the pericarp and testa and filial tissues including the endosperm and embryo. Although rice caryopsis studies have been conducted previously, a systematic characterization throughout the entire developmental process is still lacking. In this study, detailed morphological examinations of caryopses were made during the entire 30‐day developmental process. We observed some rapid changes in cell differentiation events and cataloged how cellular degeneration processes occurred in maternal tissues. The differentiations of tube cells and cross cells were achieved by 9 days after pollination (DAP). In the testa, the outer integument was degenerated by 3 DAP, while the outer layer of the inner integument degenerated by 7 DAP. In the nucellus, all tissues with the exception of the nucellar projection and the nucellar epidermis degenerated in the first 5 DAP. By 21 DAP, all maternal tissues, including vascular bundles, the nucellar projection and the nucellar epidermal cells were degenerated. In summary, this study provides a complete atlas of the dynamic changes in cell differentiation and degeneration for individual maternal cell layers of rice caryopsis. 相似文献
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Wolter, M., Seuffert, C. & Schill, R. 1988. The ontogeny of pollinia and elastoviscin in the anther of Doritis pulscherrima (Orchidaceae). - Nord. J. Bot. 8: 77–88. Copenhagen. ISSN 0107–055X.
The ontogeny of pollinia of Doritis pulcherrima shows some features not commonly found in other angiosperms. The cell wails of the mature pollinium are almost identical with those of the pollen mother cells, and a callose envelope is lacking during the formation of sporopollenin. This fact may be related to the absence of a clear substructure of the exine and its low resistance to acetolysis. An exine is found only at the outer tetrads of the pollinium. The pollen grains in the tetrads possess irregularly spaced cell walls. The ontogeny of elastoviscin (specialized pollenkitt) begins in the ground cytoplasm of some tapetal cells, where small droplets are surrounded by myelin-like structures. Before anthesis the droplets fuse, flow into the loculus, and attach the pollinia to the stipe, thus forming a pollinarium. In the region in front of the elastoviscin-producing cells, some cells with specialized helical wall thickenings develop. 相似文献
The ontogeny of pollinia of Doritis pulcherrima shows some features not commonly found in other angiosperms. The cell wails of the mature pollinium are almost identical with those of the pollen mother cells, and a callose envelope is lacking during the formation of sporopollenin. This fact may be related to the absence of a clear substructure of the exine and its low resistance to acetolysis. An exine is found only at the outer tetrads of the pollinium. The pollen grains in the tetrads possess irregularly spaced cell walls. The ontogeny of elastoviscin (specialized pollenkitt) begins in the ground cytoplasm of some tapetal cells, where small droplets are surrounded by myelin-like structures. Before anthesis the droplets fuse, flow into the loculus, and attach the pollinia to the stipe, thus forming a pollinarium. In the region in front of the elastoviscin-producing cells, some cells with specialized helical wall thickenings develop. 相似文献
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野生五唇兰菌根显微结构观察 总被引:3,自引:1,他引:2
兰科菌根菌对兰花种子萌发和原球茎生长起了重要作用,在成年阶段也扮演着重要角色(即使该兰花含有叶绿素)。为了解东南亚特有种五唇兰的菌根形态和菌根真菌的动态侵染过程,对不同生境下两种变异类型叶背绿色和叶背紫色的成年植株菌根分三个时间段采样并进行显微观察。结果表明,成年的五唇兰植株与菌根真菌有着密切关系,菌丝的侵染、定殖和消解程度随着生长发育变化而变化;在营养生长阶段和生殖生长阶段都发现菌丝结,这两个阶段的菌丝特征有所不同;而在休眠阶段的菌根中观察不到菌丝结;不同生境和不同变异类型的菌根结构无明显区别。研究结果为附生兰、地生兰和腐生兰的菌根结构的比较提供了参考。 相似文献
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Ovular morphology was examined ultrastructurally inPseudotsuga menziesii to determine the effects of the ovule on pollen development. Vesicles containing lipid-like substances traverse cell walls
of the inner epidemis of the integument and release their contents at the integument surface to form the integumentary membrane.
A major aqueous secretion from the integument into the micropylar canal is proposed to occur by the movement of the integumentary
membrane and its invaginations towards the center of the micropylar canal. The cellular degeneration of the nucellar apex
results from the breakdown of vacuoles. After this degeneration, electron-dense substances move from the prothallial cells
of the female gametophyte towards the nucellus, and many morphological changes in the nucellus, prothallial cells, and micropylar
canal take place simultaneously. We interpret these changes to result from another major secretion from the prothallial cells.
Egg cytoplasm appears to disorganize for a short time. Simultaneously, substantial amounts of electron dense-substances in
the prothallial cells and lipid-like substances in surface cell walls of the female gametophyte move towards the nucellus
as components of the third major secretion. 相似文献
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野生五唇兰根部内生真菌多样性研究 总被引:14,自引:0,他引:14
兰科植物根部的内生真菌在兰科植物的整个生活史中起着重要的作用,为了解不同生境不同类型的兰科植物内生真菌菌群的多样性,作者于2004年7月至2005年10月,以海南岛霸王岭自然保护区内的野生五唇兰(Doritis pulcherrima)作为实验材料,对不同生境、不同形态的五唇兰植株根部的内生真菌群落多样性进行了研究。从附生于石上及生于杂木林或灌丛中、叶背绿色及叶背紫红色的五唇兰植株新鲜营养根段中共分离出83株内生真菌,鉴定为19个属,其中包括培养基筛选实验中分离出的30株14属。镰刀菌属(Fusarium)(24.1%)和丝核菌属(Rhizocto-nia)(14.5%)为优势属。两种叶色的五唇兰内生真菌群落丰富度较为一致;而两种不同生境中的五唇兰内生真菌群落丰富度则表现出较大的差异:附生于灌木的五唇兰内生真菌群落Shannon多样性指数远高于附生岩石的。研究结果表明五唇兰内生真菌多样性更多地受生境的影响而不是受植株形态类型的影响。 相似文献
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《植物学报(英文版)》2016,(9)
Rice caryopsis as one of the most important food sources for humans has a complex structure that is composed of maternal tissues including the pericarp and testa and filial tissues including the endosperm and embryo. Although rice caryopsis studies have been conducted previously, a systematic characterization throughout the entire developmental process is still lacking. In this study, detailed morphological examinations of caryopses were made during the entire 30-day developmental process. We observed some rapid changes in cell differentiation events and cataloged how cellular degeneration processes occurred in maternal tissues. The differentiations of tube cells and cross cells were achieved by 9 days after pollination(DAP). In the testa, the outer integument was degenerated by 3 DAP, while the outer layer of the inner integument degenerated by 7 DAP. In the nucellus, all tissues with the exception of the nucellar projection and the nucellar epidermis degenerated in the first 5 DAP. By 21 DAP, all maternal tissues, including vascular bundles, the nucellar projection and the nucellar epidermal cells were degenerated. In summary, this study provides a complete atlas of the dynamic changes in cell differentiation and degeneration for individual maternal cell layers of rice caryopsis. 相似文献