长梗苦草雄花结构的环境扫描电镜观察

用环境扫描电子显微镜对沉水植物长梗苦草(Vallisneria longipedunculata)的雄花结构进行了观察研究。结果显示,长梗苦草雄花具3枚花被,2枚雄蕊是由3枚雄蕊中的1枚退化而来的,退化雄蕊清晰可见;花药4室,发育过程中通过药室顶端开裂,以及花药室基部的细胞收缩,将花粉粒都推到花药室的裂口处进行发育,成熟花粉粒直接外露;长梗苦草的花粉粒直径约50μm,壁薄,表面几乎没有纹饰,未发现萌发孔或萌发沟,这些是对特殊生境和传粉方式的适应。     

棉花竹花形态与结构研究

棉花竹（Fargesia fungosa）是箭竹属重要经济竹种,有关其花器官的形态与解剖结构研究至今尚无报道。本文通过对棉花竹花器官的形态与解剖结构进行观察和分析,结果显示棉花竹花序为“混合花序”,小穗基部具潜伏芽,由单个叶片形成的“佛焰苞”包裹多枚小穗。小穗单次发生,均长3.05±0.390 cm,每枚小穗具有3~7朵小花,小花均长1.85±0.167 cm,颖片2枚。每朵小花皆具有内、外稃各1片,3枚浆片,雄蕊3枚,雌蕊1枚组成。未成熟花药具有4药室,花药壁由外到内依次为表皮、药室内壁、中层和绒毡层。花药成熟后纵裂散粉。成熟花粉粒为2或3细胞型,且具有1个萌发孔。子房1室,上位,侧膜胎座,倒生胚珠,雌蕊具2分叉羽毛状柱头。花药发育异常,导致出现大量败育现象。     

新小竹花形态结构及雌、雄配子体的发育研究

新小竹(Neomicrocalamus prainii)是一种小型攀援竹类,笋秆两用型竹种。该研究通过形态观察和石蜡切片的方法对新小竹花器官形态及解剖结构特征进行观察与描述,为研究竹类植物的生殖生物学提供新的理论信息。结果显示:(1)新小竹的花序为无限花序,没有小穗柄,成熟小穗平均长度为2.98 cm;每个小穗约有4～6朵小花,其中3～5朵为可育小花,顶端均有1朵不育小花;小穗基部有2～4个苞片;小穗轴每节长约0.52 cm。(2)新小竹的可育小花包括1片内稃、1片外稃、3枚浆片(浆片2大1小,边缘光滑)、6枚雄蕊和1枚雌蕊;雄蕊呈梭型,雌蕊羽毛状柱头三裂。(3)新小竹成熟花粉粒多为二核,具1个萌发孔;花药具有4个药室,花药壁由表皮、药室内壁、中层和绒毡层4层结构组成,绒毡层为腺质型;花药发育过程还存在多种异常情况。(4)新小竹子房一室,侧膜胎座,倒生胚珠,双珠被;大孢子母细胞由1个孢原细胞直接发育而成,合点端1个大孢子分化成为功能大孢子,由功能大孢子经过有丝分裂形成多核胚囊,直至发育成熟。研究表明,新小竹雄配子体存在发育异常现象,但大部分发育正常,其结实率低不仅与内在因素有关,外部环境也可能是导致其结实率低的重要因素。     

峨眉山的几种野韭

峨眉韭(Allium omeiense Z.Y.Zhu)又名大叶韭,多年生草本植物,高50—80厘米,根粗壮。鳞茎粗1.5—2厘米。叶片长50—80厘米,宽2—3厘米。花葶圆柱形,长30—65厘米,粗4—6毫米,伞形花序,小花白色。花被片线形或线状披针形,长9—11毫米,内轮比外轮稍短。雄蕊6,花丝白色,长为花被片长的1/2,基部贴生于花被片,花药长圆形。子房近球形,3室,每室1胚珠。     

植物组织培养简报摘编

花粉粒处于单核期的花丝接种在培养基(1)上10天后,切口处产生淡黄色的愈伤组织。愈伤组织转移到培养基(2)上14天后分化出芽或根。小苗抽苔后长出黄色的花蕾,开出小花。花器小、数量少。雄蕊的花丝长度不是明显的四强雄蕊。花药壁发育尚好,花粉数量少,发育不正常,未获得种子。     

番荔枝科两种植物花器官形态发生

用扫描电镜观察了囊瓣木（Saccopetalum prolificum）和刺果番荔枝（Annona muricata）花器官的形态发生过程。刺果番荔枝和囊瓣木花被片均为3轮,其中刺果番荔枝内轮花被片数目为3枚、5枚或7枚。囊瓣木花原基最初为圆锥形,最外轮3枚花被片很快发生,之后中、内轮花被片原基连续发生,3轮花被片互生。此时花原基为六边形。花被片分化完成时,圆球形雄蕊原基沿六边形花原基的6个边螺旋向心发生,最终近轮状排列于花原基上。刺果番荔枝的雄蕊较多（约1000枚）,首先在中轮花被片所对的花原基边缘发生,之后大量雄蕊螺旋状发生。心皮分化的早期阶段,与雄蕊原基很相似,当心皮数目逐渐增多时,不能分辩出发生的顺序。成熟花中,心皮和雄蕊全都被毛覆盖,毛具有粘住传粉滴的作用。     

霉草科,缅甸被子植物一新记录科

在近期缅甸北部的植物考察中,一种菌类寄生植物矮生喜荫草(Sciaphila nana Blume)被发现和确认。矮生喜荫草代表缅甸被子植物一新记录科,霉草科植物。矮生喜荫草主要特征为花单性同株、雄花内轮花被片顶端具有柄的门把状物、花被片6、3个雄蕊、花药4室。     

二倍体芒小孢子发生及雄配子体发育研究

该实验通过采集天然二倍体芒不同发育时期的幼穗,进行卡宝品红染色压片和石蜡切片制作,观察芒的花药发育过程,为芒的生殖生物学及其系统发育研究奠定理论基础。结果表明:(1)天然二倍体芒雄蕊3枚,雄蕊花药四室,花药壁由4层细胞组成,从外向内依次是表皮、药室内壁、中层、绒毡层,花药壁发育属于基本型;花药成熟时,中层和绒毡层降解消失,或者仅存痕迹,只剩表皮和纤维层细胞,但此时可观察到部分绒毡层降解延迟现象。(2)花粉母细胞减数分裂为连续型,成熟花粉粒为3-细胞型;花粉母细胞减数分裂后期Ⅱ出现染色体分裂不同步现象。(3)雄配子体发育过程中,同一花粉囊的花粉粒发育不同步;雌、雄配子体发育也不同步,且雄蕊先成熟。     

霉草科,缅甸被子植物一新记录科（英文）

在近期缅甸北部的植物考察中,一种菌类寄生植物矮生喜荫草(Sciaphila nana Blume)被发现和确认。矮生喜荫草代表缅甸被子植物一新记录科,霉草科植物。矮生喜荫草主要特征为花单性同株、雄花内轮花被片顶端具有柄的门把状物、花被片6、3个雄蕊、花药4室。     

湖北黄精大小孢子发生及雌雄配子体发育

【目的】研究湖北黄精花部形态结构特征和大小孢子发生及雌雄配子体发育过程,以丰富黄精属植物的生殖生物学理论,为进一步开展湖北黄精的品种选育提供依据。【方法】以不同发育时期的湖北黄精花芽为试验材料,用显微观察法观察花部形态结构特征,石蜡切片技术对单花雌雄蕊进行切片观察。【结果】湖北黄精的花被为白色或淡黄绿色,花被筒近喉部稍缢缩;具6枚雄蕊,花丝下端与花被合生,花药开裂方式为纵裂;雌蕊子房上位,3心皮,花柱与子房等长。湖北黄精花药壁由4层细胞组成,成熟的绒毡层具多核,绒毡层发育类型为分泌型;小孢子母细胞减数分裂为连续型,四分体呈左右对称型排列,成熟花粉粒为2-细胞型;存在小孢子发育不同步的现象。雌蕊胚珠具双珠被、厚珠心;四分体呈直线型排列,胚囊发育类型为蓼型;存在双胚囊胚珠现象。在雄蕊的花药壁和雌蕊的子房壁都观察到有束状草酸钙针晶。【结论】湖北黄精雌雄蕊具有较原始的发育特征,虽然在发育过程中都存在异常现象,但雄蕊最终能形成正常的雄配子体,雌蕊低频率的双胚囊现象对总体受精结果影响很小。湖北黄精杂交育种可以选择花药开裂前一时期的花粉,花药壁和子房壁观察到的束状草酸钙针晶无法作为湖北黄精物种鉴定的...     

Comparative floral ontogenies among Persoonioideae including Bellendena (Proteaceae)

Floral ontogeny is described and compared in five species and four genera of the hypothetically basal proteaceous subfamily Persoonioideae sensu Johnson and Briggs. The hypotheses surrounding the origin of the peculiar proteaceous flower and homologous structures within the flowers are examined using ontogenetic morphological techniques. Ontogenetic evidence reveals that the proteaceous flower is simple, composed of four tepals, each tepal initiated successively with the lateral tepals being initiated first and second followed by the successive initiation of the sagittal tepals. Each of four stamens is initiated opposite a tepal in a similar sequence to tepal initiation. A single carpel develops terminally from the remaining floral meristem. In taxa of Persoonieae, nectaries are initiated from a broadened receptacle in alternistamenous sites after zonal growth beneath and between the tepals and stamens has begun. The nectaries are interpreted as secondary organs, not reduced homologues of a “lost” petal or stamen series. Developmental variation is present among the examined taxa in several forms including the development of a Vorlaüferspitze (spine) on the upper portion of the tepals, adnation between the anthers and tepals, and formation of the carpel. In Placospermum the early formation of the carpel cleft extends to the floral receptacle and in the other taxa, the carpel cleft is distinctly above the receptacle. Different developmental pathways result in similar mature morphologies of the carpel in Persoonia falcata and Placospermum coriaceum. Bellendena montana is unique relative to the other taxa in having free stamens, a punctate stigma, reduced (not lost) floral bracts, and the floral and bract primordia are initiated from a common meristem. This study provides a foundation for future studies of the developmental basis of floral diversity within Proteaceae.     

Mutations associated with floral organ number in rice

How floral organ number is specified is an interesting subject and has been intensively studied in Arabidopsis thaliana. In rice (Oryza sativa L.), mutations associated with floral organ number have been identified. In three mutants of rice, floral organ number 1 (fon1) and the two alleles, floral organ number 2-1 (fon2-1) and floral organ number 2-2 (fon2-2), the floral organs were increased in number centripetally. Lodicules, homologous to petals, were rarely affected, and stamens were frequently increased from six to seven or eight. Of all the floral organs the number of pistils was the most frequently increased. Among the mutants, fon1 showed a different spectrum of organ number from fon2 -1 and fon2 -2. Lodicules were the most frequently affected in fon1, but pistils of more than half of fon1 flowers were unaffected; in contrast, the pistils of most flowers were increased in fon2 -1 and fon2-2. Homeotic conversion of organ identity was also detected at a low frequency in ectopically formed lodicules and stamens. Lodicules and stamens were partially converted into anthers and stigmas, respectively. Concomitant with the increased number of floral organs, each mutant had an enlarged apical meristem. Although meristem size was comparable among the three mutants and wild type in the early phase of flower development, a significant difference became apparent after the lemma primordium had differentiated. In these mutants, the size of the shoot apical meristem in the embryo and in the vegetative phase was not affected, and no phenotypic abnormalities were detected. These results do not coincide with those for Arabidopsis in which clavatal affects the sizes of both shoot and floral meristems, leading to abnormal phyllotaxis, inflorescence fasciation and increased floral organs. Accordingly, it is considered that FON1 and FON2 function exclusively in the regulation of the floral meristem, not of the vegetative meristem.Abbreviation DIC differential interference contrast This work was supported in part by Grant-in-Aid for Scientific Research on Priority Areas from the Ministry of Education, Science and Culture of Japan.     

Developmental morphology of the flower of <Emphasis Type="Italic">Dracontium polyphyllum</Emphasis> in the context of the phylogeny of the Araceae

The inflorescence of Dracontium polyphyllum consists of 150 – 300 flowers arranged in recognisable spirals. The flower has 5 – 6 (90% of observed specimens), or 7 broad tepals enclosing 9 – 12 stamens (occasionally 7) inserted in two whorls. The gynoecium is trilocular (90% of observed specimens) or tetralocular. The tetralocular gynoecia are found at random among the trilocular gynoecia. Each locule encloses an ovule inserted in an axile position, in the median portion of the ovary. Each carpel has its own stylar canal. However, in the upper portion of the style, there is only one common stylar canal. Floral organs are initiated in an acropetal direction in the following sequence: tepals, stamens, and carpels. During later stages of development, the tepals progressively cover the other floral organs. The first floral primordia are initiated on the upper portion of the inflorescence. During early stages of development, the floral primordia have a circular shape. The tepals are initiated nearly simultaneously. During later stages of development, the first whorl of stamens develops in alternation with the tepals and is followed by a second whorl of stamens. The trilocular or tetralocular nature of the ovary is clearly visible during early stages of development of the gynoecium. Recent molecular studies show that Anaphyllopsis A. Hay and Dracontium L. are closely related. However, although pentamerous flowers have been observed in Anaphyllopsis, the developmental morphology of the flower of Dracontium is different from that of Anaphyllopsis.     

Inflorescence and floral ontogeny in Crocus sativus L. (Iridaceae)

Inflorescence and floral ontogeny of the perennial, herbaceous crop Crocus sativus L. were studied using epi-illumination light microscopy. After production of leaves with helical arrangement a determinate inflorescence forms which becomes completely transformed into a single terminal flower. In some cases, bifurcation of the inflorescence meristem yields two or three floral meristems. The order of floral organs initiation is outer tepals – stamens – inner tepals – carpels. Stamens and outer tepals are produced from the lateral bifurcation of three common stamen-tepal primordia. Within each whorl, organs start developing unidirectionally from the adaxial side, except for the stamens which begin to grow from the abaxial side. Specialized features during organ development include interprimordial growth between tepals forming a perianth tube, fusion at the base of stamen filaments, and formation of an inferior ovary with unfused styles.     

THE DEVELOPMENTAL BASIS OF TRISTYLY IN EICHHORNIA PANICULATA (PONTEDERIACEAE)

Eichhornia paniculata is a tristylous, self-compatible, emergent aquatic. A given plant produces flowers with either long, mid or short styles and two levels of stamens equal in length to the styles not found in that flower. Flowers of each morph have two whorls of three tepals, six stamens and three fused carpels. The six stamens differentiate into two sets of three stamens each. A relatively short set, having either short- or mid-level stamens, occurs on the upper side of the flower, while a relatively long set, having either mid- or long-level stamens, occurs on the lower side. Stamen level depends on differences among stamens in filament length and position of insertion on the floral tube. Floral parts arise in whorls of three, but the two stamen whorls do not form the two sets of stamens found in each mature flower. Instead, stamens from both whorls make up a given set. Floral differences among morphs are not present at flower origin or floral organ initiation. Morphological differences arise first among stamen sets. The two sets within a flower differ prior to meiosis in the size, number, and timing of comparable developmental events in the sporogenous cells. After these initial differences arise, anther size diverges. In later developmental stages differences in filament and floral tube length, cell size, and cell number, as well as differences in the length, cell size, and cell number of styles, develop among morphs. This sequence of developmental events suggests that the genes controlling development in different morphs do not control flower and floral organ initiation but are first morphologically visible in sporogenous cell differentiation.     

Floral organogenesis in Tetracentron sinense (Trochodendraceae) and its systematic significance

In Tetracentron sinense of the basal eudicot family Trochodendraceae, the flower primordium, together with the much retarded floral subtending bract primordium appear to form a common primordium. The four tepals and the four stamens are initiated in four distinct alternating pairs, the first tepal pair is in transverse position. The four carpels arise in a whorl and alternate with the stamens. This developmental pattern supports the interpretation of the flower as dimerous in the perianth and androecium, but tetramerous in the gynoecium. There is a relatively long temporal gap between the initiation of the stamens and the carpels. The carpel primordia are then squeezed into the narrow gaps between the four stamens. In contrast to Trochodendron, the residual floral apex after carpel formation is inconspicuous. In their distinct developmental dimery including four tepals and four stamens, flowers of Tetracentron are reminiscent of other, related basal eudicots, such as Buxaceae and Proteaceae.     

FLORAL ONTOGENY OF ILLICIUM FLORIDANUM,WITH EMPHASIS ON STAMEN AND CARPEL DEVELOPMENT

The ontogeny of the flower and fruit of Illicium floridanum Ellis, the Star Anise, was investigated. Each of 5 or 6 bracts in each mixed terminal bud subtends either a vegetative or floral bud. The solitary flowers occur in terminal or axillary positions. Each flower has 3–6 subtending bracteoles arranged in a clockwise helix. The flowers in our material have 24–28 tepals, 30–39 stamens, and usually 13 (rarely 19) uniovulate carpels. Tepals and stamens are initiated in a low-pitched helix; carpels later appear whorled, but arise successively at different levels on the apical flanks. The floral apex is high-convex in outline with a tunica-corpus configuration; it increases in height and width throughout initiation of the floral appendages. Tepals, stamens, and carpels are initiated by one to several periclinal divisions in the subsurface layers low on the apical flanks, augmented by cell divisions in the outer layers of the corpus. The carpel develops as a conduplicate structure with appressed, connivent margins. Procambium development of floral appendages is acropetal and continuous. Bracteoles, tepals, stamens and carpels are each supplied by 1 trace; the carpellary trace splits into a dorsal and an ascending ventral sympodium. The latter bifurcates to form 2 ventral bundles. The ovular bundle diverges from the ventral sympodium. Ovule initiation occurs in a median axillary position to the carpel, an unusual type of ovule initiation. The fruit vasculature is greatly amplified as the receptacle and follicles enlarge. After carpel initiation an apical residuum persists which is not vascularized; a plate meristem develops over its surface to produce a papillate structure.     

The Exogenous Hormornal Control of the Development of Regenerated Flower Buds in Hyacinthus orientalis

The critical role of exogenous hormone on inducing the initiation of different floral organs in the regenerated flower bud and controlling their numbers was further evidenced. The initiation of the flower buds was first induced from the perianth explants of Hyacinthus orientalis L. cv. White pearl by a combination of 2 mg/L 6-BA and 0.1 mg/L 2,4-D, and then a continuous initiation of over 100 tepals (a flower bud of H. orientalis in situ has only 6 tepals) was successfully controlled by maintenance of such a hormone concentration. However, a change of hormonal concentration (2 mg/L 6-BA and 0-0.000 1 mg/L 2,4-D) caused cessation of continuous initiation of the tepals but gave rise to induction of stamen initiation. Keeping the changed hormone concentrations could successfully control the continuous initiation of over 20 stamens (a flower bud of H. orientalis in situ has only 6 stamens). The experiment showed that the number of identical floral organs in the regenerated flower buds can be controlled by certain defined concentrations of the exogenous hormones, and the amount of the induced identical floral organs has no effect on the differentiation sequence of the different floral organs in the regenerated flower bud. Based on a systematic research on controlling the differentiation of the floral organs from both the perianth explants and the regenerated flower buds by the exogenous hormones in H. orientalis over the past decade, the authors put forward here a new idea on the role of phytohormone in controlling the automatic and sequential differentiation of the different floral organs in flower development. The main points are as follows: 1. the development of flower bud in plant is a process in which all of the floral organs are automatically and sequentially differentiated from the flower meristem. 2. Experiments in vitro showed that the effect of exogenous hormones in controlling the initiation of different floral organs is strictly concentration dependent, i.e., one kind of the floral organ can continuously and repeatedly initiate from the flower meristem as long as it is maintained in that specific concentration of the exogenous hormone which is suitable for the initiation of that particular kind of floral organ. 3. It shows that the flower buds in situ must be automatically able to adjust the endogenous hormonal concentrations just after the completion of the differentiation of one whorl of floral organ to suit the differentiation of the next whorl. Thus, the phytohormone in different concentrations takes after many change-over switches of the organ differentiation and plays a connective and regulatory role between the differentiation of every two whorls of the floral organ. In other words, these change-over switches play the roles of inhibiting the expression of the genes which control the initiation of the floral organs in the first whorl, meanwhile, activating the expression of the genes which control the initiation of the floral organs in the second whorl during the successive initiation of the different floral organs from the flower bud. It results in the automatic and sequential initiation of the various floral organs from the floral meristem.      

Floral development of Berberidopsis corallina: a crucial link in the evolution of flowers in the core Eudicots

BACKGROUND AND AIMS: On the basis of molecular evidence Berberidopsidaceae have been linked with Aextoxicaceae in an order Berberidopsidales at the base of the core Eudicots. The floral development of Berberidopsis is central to the understanding of the evolution of floral configurations at the transition of the basal Eudicots to the core Eudicots. It lies at the transition of trimerous or dimerous, simplified apetalous forms into pentamerous, petaliferous flowers. METHODS: The floral ontogeny of Berberidopsis was studied with a scanning electron microscope. KEY RESULTS: Flowers are grouped in terminal racemes with variable development. The relationship between the number of tepals, stamens and carpels is more or less fixed and floral initiation follows a strict 2/5 phyllotaxis. Two bracteoles, 12 tepals, eight stamens and three carpels are initiated in a regular sequence. The number of stamens can be increased by a doubling of stamen positions. CONCLUSIONS: The floral ontogeny of Berberidopsis provides support for the shift in floral bauplan from the basal Eudicots to the core Eudicots as a transition of a spiral flower with a 2/5 phyllotaxis to pentamerous flowers with two perianth whorls, two stamen whorls and a single carpel whorl. The differentiation of sepals and petals from bracteotepals is discussed and a comparison is made with other Eudicots with a similar configuration and development. Depending on the resolution of the relationships among the basalmost core Eudicots it is suggested that Berberidopsis either represents a critical stage in the evolution of pentamerous flowers of major clades of Eudicots, or has a floral prototype that may be at the base of evolution of flowers of other core Eudicots. The distribution of a floral Bauplan in other clades of Eudicots similar to Berberidopsidales is discussed.     

Biosystematic studies onDisporum (Liliaceae-Polygonatae)

Both the floral biology and morphometrics of two Japanese species of AsianDisporum (sectionEudisporum) are presented. These two species,D. sessile andD. smilacinum, represent extremes in both floral morphology and divergence in pollination within the section. The inverted flowers ofD. sessile have an elongate floral tube formed by the imbrication of the oblanceolate tepals. The tepal bases are modified into well developed, saccate nectaries. The stamens have rigid, vertical filaments which tightly encircle the ovary-style axis, and extrorse anthers located within a floral cavity which can accommodate a large pollinator (cross-pollination). The stigma is exserted and the depth of its cleft formation constant.D. smilacinum, in contrast, has an open, nodding campanulate flower with lanceolate tepals which have only shallow nectaries at their bases. The stamens have widely divergent filaments with versatile anthers that have laterally introrse dehiscence (wind and/or self-pollination). The depth of the stigma cleft is variable. For both species, the pattern of differential UV absorption and reflectance is similar. It is suggested on morphological grounds and by pollinator observation, thatD. sessile with a high energy flower requiring specialized visitors represents a more advanced condition than that observed inD. smilacinum, which is more generalized and primitive. Seasonal herbivore pressure on the tepal nectaries ofD. sessile is discussed in relation to its pollination.