黄杨花蜜腺的形态解剖学研究

黄杨花单性,雌雄同株,雄花花蜜腺４枚,乳头状,着生于退化雌蕊子房顶部;雌花花蜜腺３枚,短柱状,位于３枚花柱之间。雌、雄花蜜腺均由分泌表皮、产蜜组织和维管束构成,在发育过程中产蜜组织细胞的液泡都发生有规律的变化。雌花蜜腺大,属非淀粉型蜜腺,泌蜜量大,蜜汁含糖分多,维管束中仅含韧皮部;雄花蜜腺小,属淀粉型蜜腺,泌蜜量小．蜜汁含糖量小,维管束由木质部和韧皮部构成。     

Structure of the receptacular nectary and circadian metabolism of starch in the ant‐guarded plant Ipomoea cairica (Convolvulaceae)

Nectaries occur widely in Convolvulaceae. These structures remain little studied despite their possible importance in plant–animal interactions. In this paper, we sought to describe the structure and ultrastructure of the receptacular nectaries (RNs) of Ipomoea cairica, together with the dynamics of nectar secretion. Samples of floral buds, flowers at anthesis and immature fruits were collected, fixed and processed using routine methods for light, scanning and transmission electron microscopy. Circadian starch dynamics were determined through starch measurements on nectary sections. The secretion samples were subjected to thin layer chromatography. RNs of I. cairica were cryptic, having patches of nectar‐secreting trichomes, subglandular parenchyma cells and thick‐walled cells delimiting the nectary aperture. The glandular trichomes were peltate type and had typical ultrastructural features related to nectar secretion. The nectar is composed of sucrose, fructose and glucose. Nectar secretion was observed in young floral buds and continued as the flower developed, lasting until the fruit matured. The starch content of the subglandular tissue showed circadian variation, increasing during the day and decreasing at night. The plastids were distinct in different portions of the nectary. The continuous day–night secretory pattern of the RNs of I. cairica is associated with pre‐nectar source circadian changes in which the starch acts as a buffer, ensuring uninterrupted nectar secretion. This circadian variation may be present in other extrafloral nectaries and be responsible for full daytime secretion. We conclude that sampling time is relevant in ultrastructural studies of dynamic extranuptial nectaries that undergo various changes throughout the day.     

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     

长药景天花蜜腺的发育解剖学研究

长药景天花蜜腺５枚,呈侧向扁平的舌形或弯月形,分别位于５株离生心皮的外侧,两者的基部相连,属于子房蜜腺。蜜腺由分泌表皮、产蜜组织和仅含韧皮部的维管束组成。长药景天花蜜腺起源于心皮外侧基部的表层结构。产蜜组织在发育过程中,细胞中的液泡体积及淀粉粒呈现有规律的消长变化。泌蜜后期,蜜腺组织从上往下液泡化,具明显的方向性。根据其结构及多糖变化分析,来自韧皮部的原蜜汁以淀粉粒形式贮存于产蜜组织中,泌蜜期水解     

Influence of light,dark, temperature and drought on metabolite and ion composition in nectar and nectaries of an epiphytic bromeliad species (Aechmea fasciata)

• Research into the influence of stress factors, such as drought, different temperatures and/or varied light conditions, on plants due to climate changes is becoming increasingly important. Epiphytes, like many species of the Bromeliaceae, are particularly affected by this, but little is known about impacts on nectar composition and nectary metabolism.
• We investigated the influence of drought, different temperatures and light–dark regimes on nectar and nectaries of the epiphytic bromeliad species, Aechmea fasciata, and also the influence of drought with the terrestrial bromeliad, Billbergia nutans. The content of sugars, amino acids and ions in nectar and nectaries was analysed using HPLC. In addition, the starch content and the activities of different invertases in nectaries were determined.
• Compositions of nectar and nectaries were hardly influenced, neither by light nor dark, nor by different temperatures. In contrast, drought revealed changes in nectar volumes and nectar sugar compositions in the epiphytic bromeliad as well as in the terrestrial bromeliad. In both species, the sucrose‐to‐hexose ratio in nectar decreased considerably during the drought period. These changes in nectar sugar composition do not correlate with changes in the nectaries. The total sugar, amino acid and ion concentrations remained constant in nectar as well as in nectaries during the drought period.
• Changes in nectar composition or in the production of floral pollinator rewards are likely to affect plant–pollinator interactions. It remains questionable how far the adaptations of the bromeliads to drought and diverse light or temperature conditions are still sufficient.

     

木薯品种(系)类胡萝卜素代谢相关基因和蛋白表达水平分析

以白心木薯华南6068、华南9号、紫叶黄心木薯BGM019和粉红木薯Mirasol为材料,探究木薯块根膨大期和成熟期与类胡萝卜素代谢通路相关的14个基因和4种蛋白质表达水平变化。用HPLC检测块根β-胡萝卜素含量的变化,分别用qRT-PCR和Western blot方法对类胡萝卜素代谢通路相关基因和蛋白酶的表达水平进行分析。以华南6068为对照,研究结果表明:华南9号和紫叶黄心木薯BGM019成熟期中的类胡萝卜素合成途径关键基因PSY2、LCYB基因显著高于膨大期,而降解相关的关键基因CCD1、NCED3在成熟期的表达量显著低于膨大期(P0.05)。粉红木薯Mirasol成熟期中PSY2、LCYB的显著下调与CCD1、NCED3的显著上调(P0.05)是造成β-胡萝卜素含量差异的原因之一。通过分析不同木薯品种(系)在膨大期和成熟期块根类胡萝卜素代谢途径相关基因的表达水平,有助于解析β-胡萝卜素积累的分子机理。此外,Western blot结果显示抗坏血酸过氧化物酶、谷胱甘肽还原酶、超氧化物歧化酶和HSP70虽然和块根类胡萝卜素代谢途径没有直接关联,但它们在木薯膨大期和成熟期块根表达水平有显著差异(P0.05)。     

Preparation of protoplasts of the fungus <Emphasis Type="Italic">Trametes hirsuta</Emphasis> 072 and study of the effect of antioxidants on their formation and regeneration

The consistent application of homogenization and enzymatic treatment is required to obtain protoplasts from the basidiomycete fungus Trametes hirsuta. The maximum yield of protoplasts (～2.5 × 10⁷/mL) was achieved when mycelium in the exponential growth phase (60 h) was used. The maximum stability was observed in MES⁺ buffer during 4 h of incubation; in this case the titer reduction was 5–7%. Studies of the effect of antioxidants with different antioxidant capacities expressed in mmol equivalents of Trolox (ascorbate, 0.99; α-tocopherol, 1.0; β-carotene, 2.14; quercetin, 3.98) indicated that the yield of protoplasts was increased in the presence of β-carotene and quercetin by 18–24%. The studied antioxidants did not affect the protoplasts stability. The degree of regeneration of protoplasts correlated with the antioxidant capacity of the studied antioxidants and was maximal (0.4%) in the presence of β-carotene and quercetin; it was 0.1% in the presence of MES⁺. The rate of protoplast growth was two times higher in the presence of β-carotene and quercetin.     

NEC1, a novel gene, highly expressed in nectary tissue of Petunia hybrida

To study the molecular regulation of nectary development, we cloned NEC1, a gene predominantly expressed in the nectaries of Petunia hybrida, by using the differential display RT-PCR technique. The secondary structure of the putative NEC1 protein is reminiscent of a transmembrane protein, indicating that the protein is incorporated into the cell membrane or the cytoplast membrane. Immunolocalization revealed that NEC1 protein is present in the nectaries. Northern blot analyses showed that NEC1 is highly expressed in nectary tissue and weakly in the stamen. GUS expression driven by the NEC1 promoter revealed GUS activity in the outer nectary parenchyma cells, the upper part of the filament and the anther stomium. The same expression pattern was observed in Brassica napus. GUS expression was observed as blue spots on the surface of very young nectaries that do not secrete nectar and do accumulate starch. GUS expression was highest in open flowers in which active secretion of nectar and starch hydrolysis had taken place. Ectopic expression of NEC1 resulted in transgenic plants that displayed a phenotype with leaves having 3-4 times more phloem bundles in mid-veins than the wild-type Petunia. The possible role of NEC1 gene in sugar metabolism and nectar secretion is discussed.     

Nectar, nectaries, flower visitors, and breeding system in five terrestrial Orchidaceae from central Argentina

Floral nectar sugar composition, nectary anatomy, and visitors are studied in five Argentine Orchidaceae, from 18 populations. Hand-pollinations were performed to evaluate their breeding system. We found two different types of perigonal nectaries located either in the spur (Habenaria gouriieana, H. hieronymi, Habenariinae), or in the basal lateral parts of the labellum (Beadlea dutraei, Pelexia bonariensis, Stenorrhynchos orchioides, Spiranthinae). The spur ofHabenaria is a nonvascularised and nonstructural nectary. The inner epidermis bears one-celled long papillae. In bud stage, the papillae are filled with starch grains, but when the flower opens and nectar secretion starts, they show no starch grains. This fact may indicate that starch is a source for some of the secreted nectar. In the remainder genera, the lateral basal parts of the labellum are secretory. The two glands are located in the adaxial basal lateral faces of the labellum. These nectaries are structural and nonvascularised.Stenorrhynchos produces abundant, concentrated nectar (40–50%).Habenaria gourlieana accumulates copious nectar in a lower concentration (<20%), whereas the other species produce small quantities of concentrated nectar (ca. 50%). Three of the studied species have sucrose predominant nectar (Beadlea dutrael, Habenaria gourlieana, andPelexia bonariensis) whileH. hieronymi, Stenorrhynchos orchioides have hexose predominant ones. Nectar removal and/or pollination induce flower senescence.H. gouriieana is visited by sphingids,S. orchioides by hummingbirds, andB. dutrael by bees. For the two other species we did not record flower visitors.Pelexia bonariensis, B. dutrael, andS. orchiodes are self-compatible species but a pollinator is needed.     

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。     

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。     

Floral nectar production and carbohydrate composition and the structure of receptacular nectaries in the invasive plant <Emphasis Type="Italic">Bunias orientalis</Emphasis> L. (Brassicaceae)

The data relating to the nectaries and nectar secretion in invasive Brassicacean taxa are scarce. In the present paper, the nectar production and nectar carbohydrate composition as well as the morphology, anatomy and ultrastructure of the floral nectaries in Bunias orientalis were investigated. Nectary glands were examined using light, fluorescence, scanning electron and transmission electron microscopy. The quantities of nectar produced by flowers and total sugar mass in nectar were relatively low. Total nectar carbohydrate production per 10 flowers averaged 0.3 mg. Nectar contained exclusively glucose (G) and fructose (F) with overall G/F ratio greater than 1. The flowers of B. orientalis have four nectaries placed at the base of the ovary. The nectarium is intermediate between two nectary types: the lateral and median nectary type (lateral and median glands stay separated) and the annular nectary type (both nectaries are united into one). Both pairs of glands represent photosynthetic type and consist of epidermis and glandular tissue. However, they differ in their shape, size, secretory activity, dimensions of epidermal and parenchyma cells, thickness of secretory parenchyma, phloem supply, presence of modified stomata and cuticle ornamentation. The cells of nectaries contain dense cytoplasm, plastids with starch grains and numerous mitochondria. Companion cells of phloem lack cell wall ingrowths. The ultrastructure of secretory cells indicates an eccrine mechanism of secretion. Nectar is exuded throughout modified stomata.     

THE FLORAL AND EXTRA-FLORAL NECTARIES OF PASSIFLORA. I. THE FLORAL NECTARY

Floral nectary development and nectar secretion in three species of Passiflora were investigated with light and electron microscopy. The nectary ring results from the activity of an intercalary meristem. Increased starch deposition in the amyloplasts of the secretory cells parallels maturation of the nectary phloem. Large membrane-bound protein bodies are observed consistently in phloem parenchyma cells, but their function is presently unknown. The stored starch serves as the main source of nectar sugars at anthesis. Plastid envelope integrity is maintained during starch degradation, and there is no evidence of participation of endoplasmic reticulum or Golgi in the secretion of pre-nectar. It is concluded that in these starchy nectaries granulocrine secretion, commonly reported for floral nectaries, does not occur.     

芭蕉科花蜜腺形态比较: 兼论其与传粉者的关系

对狭义芭蕉科3个属的代表性种芭蕉(Musa basjoo)、象腿蕉(Ensete glaucum)和地涌金莲(Musella lasiocarpa)的花蜜腺形态进行了比较研究。结果表明它们的蜜腺属于隔膜蜜腺。雌花的蜜腺着生于子房的上部, 胚珠的上方; 雄花蜜腺占据了整个败育子房的位置。蜜腺结构由许多腔道组成, 这些腔道在横切面上呈现出复杂的发散式迷宫状结构。这3种植物花蜜腺的栅栏状表皮细胞、维管束和蜜腺开口方式相似, 而从纵切面和横切面上观察其结构存在一些差异。PAS反应显示象腿蕉泌蜜组织中淀粉粒含量高于其他两个种; 芭蕉和象腿蕉的蜜腺腔里有许多纤维状物质存在。3种植物的传粉综合征多样化, 花序和花的特征(如花序下垂或直立、苞片的颜色、泌蜜量和泌蜜时间等)和传粉样式之间有密切关系。它们的蜜腺结构和传粉者行为之间没有明显的相关性, 但是胶质或水质的花蜜对传粉者的取食方式有一定影响。     

芭蕉科花蜜腺形态比较：兼论其与传粉者的关系（英文）

对狭义芭蕉科3个属的代表性种芭蕉(Musa basjoo)、象腿蕉(Ensete glaucum)和地涌金莲(Musella lasiocarpa)的花蜜腺形态进行了比较研究。结果表明它们的蜜腺属于隔膜蜜腺。雌花的蜜腺着生于子房的上部,胚珠的上方;雄花蜜腺占据了整个败育子房的位置。蜜腺结构由许多腔道组成,这些腔道在横切面上呈现出复杂的发散式迷宫状结构。这3种植物花蜜腺的栅栏状表皮细胞、维管束和蜜腺开口方式相似,而从纵切面和横切面上观察其结构存在一些差异。PAS反应显示象腿蕉泌蜜组织中淀粉粒含量高于其他两个种;芭蕉和象腿蕉的蜜腺腔里有许多纤维状物质存在。3种植物的传粉综合征多样化,花序和花的特征(如花序下垂或直立、苞片的颜色、泌蜜量和泌蜜时间等)和传粉样式之间有密切关系。它们的蜜腺结构和传粉者行为之间没有明显的相关性,但是胶质或水质的花蜜对传粉者的取食方式有一定影响。     

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。     

油菜花蜜腺发育过程的超微结构变化与泌蜜机理的研究

油菜花蜜腺由２枚侧蜜腺和２枝中蜜腺组成,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泡都发生有规律变化。泌蜜前,细胞器的数量增加。其中,质体内积累淀粉,此过程与蜜腺内初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质体、内质网和高尔基体内加工成蜜汁,最后通过胞吐和渗透相结合的方式泌出。