油菜花蜜腺发育过程的超微结构变化与泌密机理的研究

油菜花蜜腺由２枚侧蜜腺和２枚中蜜腺组成,其基本结构类似。在蜜腺发育过程中,产蜜组织细胞内的内质网、高尔基体、质体和线粒体以及液孢都发生有规律变化。泌蜜前,细胞器的数量增加。其中,质体内积累淀粉,此过程与蜜腺内韧皮部的分化并和线粒体的增加相关。泌蜜时,内质网数量增多,并产生小泡,小泡向质膜移动。泌蜜后,细胞液泡化,细胞器数量减少,细胞萎缩。根据观察结果分析,其原蜜汁来源于韧皮部,转运至产蜜组织细胞的     

荇菜成熟花蜜腺的形态及其泌蜜过程的超微结构研究

荇菜花蜜腺共五枚,黄色,肾形,着生子房基部。它们由分泌表皮和泌蜜组织组成,属结构蜜腺。成熟蜜腺的分泌表皮具明显的角质层和气孔,还具少量短期生活的分泌毛,分泌毛不具明显的角质层。泌蜜组织具较小的胞间隙,胞间连丝发达。成熟蜜腺细胞中不人有丰富的线粒体,内质网,还有大量的质体。     

油菜花蜜腺的发育过程及组织化学变化

油菜花蜜腺４枚,２故侧蜜腺和２枚中蜜腺。蜜腺由分泌表皮、产蜜组织和维管束组成。蜜腺原基是在花的各部分原基发生后,由花托局部区域的表面数层细胞经反分化形成。但它在短期内,完成了形态建成,与花的成熟同步。在蜜腺的发育过程中,产蜜组织细胞的液泡发生有规律的变化。同时,淀粉粒、蛋白质的动态也较为明显,以上变化与蜜汁的合成和分泌密切相关。其蜜腺的原蜜汁是由韧皮部提供,运转至产蜜组织内加工,最后由变态气孔和泌蜜通道泌出。     

拟南芥花蜜腺筛分子及蜜腺组织发育过程中的细胞学研究

应用高压冷冻和低温替代技术,以拟南芥（Arabidopsis thalanaL.)花蜜腺发育过程中细胞的超微结构变化进行了研究。蜜腺组织中深色细胞的超微结构与筛分子早期分化的超微结构十分相似;细胞核中染色质逐渐出现凝集并且边缘化;细胞器分布异常;细胞质浓稠,这些超微结构特征与近年来报道的动植物细胞程序性死亡的超微结构相似,在筛分子和深色细胞分化中,细胞核及一些细胞器的逐渐解体与原蜜汁的运输,加工和蜜汁的分泌有直接联系,这反映了蜜腺发育过程中筛分子和蜜腺组织的细胞学变化是与蜜腺的生长,发育和生理功能的完善联系在一起的。     

荇菜花蜜腺的发育研究

荇菜花蜜腺的发育过程可分为：起源期、生长期、分泌期以及泌蜜停止期等４个时期。荇菜的５枚花蜜腺均起源于子房基部的表皮及表皮内的２－４层细胞。这些细胞经反分化后分别成为蜜腺的原分泌表皮及原泌蜜组织,两部分细胞径不断地分裂分化,最冬成为成熟蜜腺。在蜜腺发育过程中,蜜腺的分泌表皮及蜜腺组织内的内质网、质体、线粒体、液泡等细胞器结构均发生了有规律的变化,内质网在蜜腺分泌期最为发达,且产生大量的分泌小泡。质体     

拟南芥花蜜腺筛分子及蜜腺组织发育过程中的细胞学研究

应用高压冷冻和低温替代技术,对拟南芥(Arabidopsis thaliana L.)花蜜腺发育过程中细胞的超微结构变化进行了研究.蜜腺组织中深色细胞的超微结构与筛分子早期分化的超微结构十分相似:细胞核中染色质逐渐出现凝集并且边缘化;细胞器分布异常;细胞质浓稠.这些超微结构特征与近年来报道的动植物细胞程序性死亡的超微结构相似.在筛分子和深色细胞分化中,细胞核及一些细胞器的逐渐解体与原蜜汁的运输、加工和蜜汁的分泌有直接联系.这反映了蜜腺发育过程中筛分子和蜜腺组织的细胞学变化是与蜜腺的生长、发育和生理功能的完善联系在一起的.     

龙眼花蜜腺的发育解剖学研究

对龙眼(Dimocarpus longan Lour.)花蜜腺的形态结构、发育过程以及蜜腺的组织化学变化进行了较为系统的研究;对花蜜腺结构与泌蜜的关系、泌蜜方式、起源和系统演化等作了初步的探讨。结果表明：龙眼的花盘蜜腺位于花托上,呈环状环绕在雌雄蕊基部外围,花芽分化约30d,在雄蕊和花被之间的花托表面,蜜腺原基也开始形成,由花托表面2～3层细胞脱分化形成居间分生组织发育而来;龙眼花蜜腺由分泌表皮和产蜜组织构成,属结构蜜腺;分泌表皮角质层极薄,密布单细胞绒毛,未发现有气孔;产蜜组织由亚腺细胞、产蜜细胞、油细胞和维管束组成;在蜜腺发育过程中,产蜜细胞的液泡和多糖物质发生有规律的变化;蜜腺的原蜜汁来源于韧皮部,蜜汁经表皮角质层渗出。     

沙枣花蜜腺的发育解剖学研究

沙枣的花蜜腺位于花柱基部的筒状花盘上,属花盘蜜腺,其蜜腺位于花盘外方,由分履表皮和产蜜组织组成。分泌表皮具有角质层和变态的气孔器。产蜜组织在发育过程中,其液泡和淀粉粒都随着蜜腺的发育呈现一定的消长规律,最后形成的蜜汁由盘状蜜腺表面的气孔泌出。     

芫荽花蜜腺的发育解剖学研究

芫荽的花蜜腺位于子房上部盘状结构上,属于下位子房上部的花盘蜜腺。蜜腺由分泌表皮和产蜜组织构成。分泌表皮具厚的呈波纹状皱折的角质层,层皮上分布有下陷的变态气孔。产蜜组织细胞４－５层,其下有３－４层大型薄壁细胞与来自子房壁的维管束相毗邻。芫荽花蜜腺发育较晚,在子房发育后期由花盘表面的１－２层细胞恢复分裂能力形成蜜腺组织。产蜜组织细胞在发育过程中,液泡、淀粉粒都呈现一定的消第长规律。根据其结构及泌蜜前后     

Anatomy and ultrastructure of the floral nectary in Peganum harmala L. (Nitrariaceae)

Anatomy and ultrastructure of the floral nectary of Peganum harmala L. were studied using light and transmission electron microscopy. The floral nectary was visible as a glabrous, regularly five‐lobed circular disc encircling the base of the ovary. Anatomically, it comprised a single layered epidermis and 15–20 layers of small, subepidermal secretory cells overlying several layers of large, ground parenchyma cells. The floral nectary was supplied by phloem and both sieve tubes and companion cells were found adjacent to the ground parenchyma. Based on our ultrastructural observations, plastids of secretory cells during the early stages of development were rich in starch grains and/or osmiophilic plastoglobuli, but these disappeared as nectar secretion progressed. The nectar appeared to exude through the modified stomata along symplastic and apoplastic routes. The abundant plastids and mitochondria suggest an eccrine mechanism of nectar secretion in P. harmala.     

垂花青兰花蜜腺的发育解剖学研究

垂花青兰（Dracocephalum nutans Linn.）花蜜腺分布于子房基部的花托上,盘状蜜腺的上部裂成三小一大的四枚裂片,基部在膨大的花托外环绕一圈。蜜腺组织由分泌表皮、产蜜组织和维管束三部分组成,是典型的结构蜜腺;组织化学染色显示淀粉粒动态明显,因此又属淀粉蜜腺。在发育的过程中细胞液泡化动态明显,且淀粉粒和蛋白质具有明显的消长变化,蜜汁通过气孔器和表皮细胞的角质层泌出。     

葡萄两性花花蜜腺的发育解剖学研究

葡萄两性花的花蜜腺位于子房基部的花盘上,共5枚,呈椭圆形,与雄蕊相间排列,属于花盘蜜腺,蜜腺由表皮和泌蜜组织组成,缺乏维管束,表皮具薄的角质层,无气孔器,蜜腺原基由子房基部表层细胞恢复分裂能力形成,在蜜腺发育过程中,泌蜜组织的液泡规律 性变化和多糖动态变化均不明显,原蜜汁由子房维管束的韧皮部提供,蜜汁通过表皮细胞排出。     

獐牙菜属四种植物花蜜特征的比较

花蜜的分泌特征在种间、种内以及植株内不同花朵间的变异决定了花朵对访花动物的吸引和访花模式, 进而影响传粉效率和植物繁殖成功。然而, 我们对花蜜分泌特征变异性的认识还不够深入, 缺乏野外实验数据。研究选取龙胆科獐牙菜属(Swertia) 4种同域分布的植物, 即獐牙菜(S. bimaculata)、西南獐牙菜(S. cincta)、贵州獐牙菜(S. kouitchensis)和紫红獐牙菜(S. punicea)为研究对象, 开展花蜜特征及其变异性的研究。通过比较种内套袋24 h和自然状况下花朵的3个花蜜特征, 即花蜜体积、糖浓度和含糖量(重量)的异同, 以及同一植株不同花朵间花蜜特征的差异, 试图阐明花蜜特征在种间、种内植株间和个体内的变异性。结果显示獐牙菜属4种植物的花蜜特征有显著差异; 套袋24 h处理和自然状态花朵的花蜜特征大多有显著差异, 仅有獐牙菜和贵州獐牙菜的糖浓度在两种处理间差异不显著; 相邻两朵花的糖浓度都具有显著正相关, 然而, 花蜜体积和糖含量在相邻花朵间的相似性较低; 相邻两朵花花蜜特征的正相关在套袋处理花中高于自然状态, 显示自然状态下花蜜特征的高变异性。研究结果表明花蜜的变异性包括: (1)花蜜的种间差异可能与传粉昆虫类群有关; (2)同一植株相邻花朵间花蜜糖浓度显著相关, 表明花蜜体积和含糖量相互调节使得花蜜糖浓度保持在相似区间内; (3)花蜜特征在个体间和花朵间较高的变异性可促使传粉者在植株间访问, 从而提升植物繁殖成功率。     

Floral nectar production and nectary anatomy and ultrastructure of Echinacea purpurea (Asteraceae)

BACKGROUND AND AIMS: In spite of the impressive species diversity in the Asteraceae and their widespread appeal to many generalist pollinators, floral-nectary ultrastructure in the family has rarely been investigated. To redress this, a study using Echinacea purpurea, a plant of horticultural and nutraceutical value, was undertaken. Nectar secretion of disc florets was compared with floral nectary ultrastructure taking into account nectar's potential impact upon the reproductive success of this outcrossing species. METHODS: Micropipette collections of nectar in conjunction with refractometry were used to determine the volume and nectar-sugar quantities of disc florets throughout their phenology, from commencement of its production to cessation of secretion. Light, scanning-electron and transmission-electron microscopy were utilized to examine morphology, anatomy and ultrastructure of nectaries of the disc florets. KEY RESULTS: Florets were protandrous with nectar being secreted from anthesis until the third day of the pistillate phase. Nectar production per floret peaked on the first day of stigma receptivity, making the two innermost whorls of open florets most attractive to foraging visitors. Modified stomata were situated along the apical rim of the collar-like nectary, which surrounds the style base and sits on top of the inferior ovary. The floral nectary was supplied by phloem only, and both sieve elements and companion cells were found adjacent to the epidermis; the latter participated in the origin of some of the precursor cells that yielded these specialized cells of phloem. Companion cells possessed wall ingrowths (transfer cells). Lobed nuclei were a key feature of secretory parenchyma cells. CONCLUSIONS: The abundance of mitochondria suggests an eccrine mechanism of secretion, although dictyosomal vesicles may contribute to a granulocrine process. Phloem sap evidently is the main contributor of nectar carbohydrates. From the sieve elements and companion cells, an apoplastic route via intercellular spaces and cell walls, leading to the pores of modified stomata, is available. A symplastic pathway, via plasmodesmata connecting sieve elements to companion, parenchyma and epidermal cells, is also feasible. Uncollected nectar was reabsorbed, and the direct innervation of the nectary by sieve tubes potentially serves a second important route for nectar-sugar reclamation. Microchannels in the outer cuticle may facilitate both secretion and reabsorption.