Inflorescence and flower development in the Hedychieae (Zingiberaceae): Scaphochlamys kunstleri (Baker) Holttum

Primary inflorescence bracts are initiated in a spiral phyllotactic pattern on the flanks of the inflorescence apex. A cincinnus primordium forms in the axil of each primary bract. A prophyll is initiated in the transverse plane and later extends around the periphery of the cincinnus to produce a sheathing, but not tubular, bract. The apex of the cincinnus forms a flower. Flower development begins with the enlargement and flattening of the floral apex. Sepal initiation is sequential but differs in the first two flowers of a cincinnus. The different sequences are likely the result of developmental constraints that operate at the time of sepal initiation. After initiation, the margins of the sepals become confluent and intercalary growth produces the synsepalous calyx. The periphery of the flower, interior to the sepals, now rises to form a ring primordium composed of three common petallandroecial primordia. The common primordia enlarge, flatten, and separate to produce a petal to the exterior and an androecial member to the interior. The outer androecium forms in the regions of the ring primordium left vacant by the formation of the other floral parts. The anterior outer androecial member soon ceases growth and contributes only initially to the formation of the labellum. The gynoecium shows heterochrony in its time of initiation, which occurs much earlier than in other species of Zingiberaceae. Gynoecial initiation takes place on the margins of the central flora cup, at the time of the separation of the common primordia. Three gynoecial primordia from in antipetalous positions. Septa development differs in the basal and apical portions of the ovary. At the base, the primordia grow inward and fuse to form the central axis of the ovary. At the apex, there is little radial growth of the primordia. They cease growth soon after initiation and produce a unilocular cavity. Ovules form at the junction of these two regions and project up into the cavity. Epigynous nectaries form after all other floral organs

A holistic aesthetic for science.

All scientific work takes place within a community of specialists who define what types of studies, evidence and modes of presentation are accepted as valid. A number of factors influence these decisions. Among them are tacit assumptions hidden in the language and practice of science. In recent years, philosophers, historians, linguists and feminist critics of science have elucidated some of these assumptions. The result has been a recognition that at least some scientific decisions are made simply because they "feel right." In other words, science possesses an aesthetic. After reviewing the evidence for the role of a scientific aesthetic, I suggest the conscious adoption of a new aesthetic based on love. Adoption of this aesthetic can lead us to change our relationship to the phenomena we study. Where Western science has mainly been concerned with the control of nature, an aesthetic of love can lead to an appreciation of the wisdom of nature. Instead of searching for causes, a science based on love can lead to a study of the patterns of phenomena. Within these patterns no single element is determinative. Rather, the pattern as a whole determines the role of the individual elements. Traditional Chinese Medicine serves as a powerful example of the capabilities of this pattern thinking approach

Epi- illumination microscopy coupled to in situ hybridization and its utility in the study of evolution and development in non-model species

Evolutionary developmental biology often combines methods for examining morphology (e.g., scanning electron microscopy, SEM) with analyses of gene expression (e.g., RNA in situ hybridization). Due to differences in tissue preparation for SEM and gene expression analyses, the same specimen cannot be used for both sets of techniques. To aid in the understanding of morphological variation, it would be particularly useful to have a high- magnification image of the very same sample in which gene expression is subsequently analyzed. To address this need, we developed a method that couples extended depth of field (EDF) epi-illumination microscopy to in situ hybridization in a sequential format, enabling both surface microscopy and gene expression analyses to be carried out on the same specimen. We first created a digital image of inflorescence apices using epi-illumination microscopy and commercially available EDF software. We then performed RNA in situ hybridizations on photographed apices to assess the expression of two developmental genes: Knottedl(Knl) in Zea mays (Poaceae) and a PISTILLATA (PI) homolog in Musa basjoo (Musaceae). We demonstrate that expression signal is neither altered nor reduced in the imaged apices as compared with the unphotographed controls. The demonstrated method reduces the amount of sample material necessary for developmental research, and enables individual floral development to be placed in the context of the entire inflorescence. While the technique presented here is particularly relevant to floral developmental biology, it is applicable to any research where observation and description of external features can be fruitfully linked with analyses of gene expression

Character description in phylogenetic analysis: insights from Agnes Arber's concept of the plant

Throughout her work Agnes Arber argues for an inclusive, synthetic concept of the vascular plant as `consisting of a unification of every phase of its existence'. Her view of the leaf as a partial-shoot reflects this unification by relating the part (leaf) to the whole (shoot). According to Arber's view of the plant, the part can be fully understood only in the context of the whole. Morphological character description as it is currently practiced in systematics isin sharp contrast with this holistic view of plant structure. Systematic characters are removed from their context when they are described. This problem is greatest when characters are expressed verbally. Verbal descriptions convey little of the content of the character. A shift from verbal to visual charactersallows systematists to capture more information, including some of the context in which the character occurs. By using a photograph, the fringe on a labellum of Alpinia spp. (Zingiberaceae) can be viewed in the context of the labellum in a way that the word `fringe' cannot convey. The use of pictorial charactersalso allows reliable data storage and retrieval from databases, much as DNA sequences are currently being stored and retrieved. Key words: Agnes Arber, character concept, character state, cladistics, database, holism, partial-shoot theory, phylogeny, phylogenetic systematics, plant morphology, process morphology, typology

On the relationship between phyllotaxy and vasculature

There is a definite relationship between the phyllotactic fraction and the sympodia uniting median leaf traces in a stem. The denominator of the phyllotactic fraction is the number of sympodia in the -stem, and the numerator is the -number of sympodia counted in passing from the sympodium of one leaf to that of an adjacent leaf on the genetic helix. This relationship holds for species with closed as well as open vascular systems. Of the 100 shoots (93 species) whose vasculature has been reviewed from the literature only one shows no apparent relationship between the phyllotactic fraction and the vasculature. Shoots for 87 species show the relationship described above while shoots of five species have both irregular phyllotaxis and vasculature. The mathematical constraints on this relationship are shown to depend on the divergence angle and the fact that sympodia do not cross one another. That there are biological controls on this relationship in addition to the purely mathematical ones is shown by the fact that sympodial connections are almost universally made along orthostichies. These controls most likely operate on factors that influence the formation of orthostichies such as the relationship between leaf-shape and use of the apical dome

Developmental evidence helps resolve the evolutionary origins of anther appendages in Globba (Zingiberaceae)

Globba is one of the largest genera in the primarily tropical Zingiberaceae. The number of anther appendages is highly diagnostic and has been used along with molecular characters to define subgenera and sections. Four main types of anther morphology are recognized: without appendages and with two, four and six appendages. The six-appendaged anthers are reported here for the first time. Appendages arise from two dorsal ledges that flank the broad connective. Development of two-appendaged and four-appendaged species differs from inception. Previous suggestions that either the proximal or distal appendages of four-appendaged anthers have been lost in two-appendaged species are thus not supported. Early development of six-appendaged anthers is similar to that of four-appendaged species, but two additional, small appendages develop on the ledges between the first-formed appendages. This yields three appendages on each side (six overall). The four appendages of G. geoffrayi differ from all other species in having distal appendages that are much smaller and develop later than the proximal appendages. Development thus suggests that the state in G. geoffrayi evolved from a two-appendaged ancestor. Incorporating this information into a phylogenetic character plot of the number of appendages shows that the possession of two appendages is the most likely plesiomorphic state of the genus, although support for this hypothesis is weak. Our study clarifies the origin and complexity in the development of anther appendages in Globba and highlights their significance in infrageneric relationships in Globba. Two appendages have probably likely arisen at the base of Globba, linked with the presence of a prominent ledge, with variable extensions and reductions of the number of appendages in the various subgenera and sections

Plant Structure Ontology: How to label plant structures with doubtful or mixed identities?

This paper discusses problems with labelling plant structures in the context of attempts to create a unified Plant Structure Ontology. Special attention is given to structures with mixed, or doubtful identities that are difficult or even impossible to label with a single term. In various vascular plants (and some groups of animals) the structural categories for the description of forms are less distinct than is often supposed. Thus, there are morphological misfits that do not fit exactly into one or the other category and to which it is difficult, or even impossible, to apply a categorical name. After presenting three case studies of intermediate organs and organs whose identity is in doubt, we review five approaches to categorizing plant organs, and evaluate the potential of each to serve as a general reference system for gene annotations. The five approaches are (1) standardized vocabularies, (2) labels based on developmental genetics, (3) continuum morphology, (4) process morphology, (5) character cladograms. While all of these approaches have important domains of applicability, we conclude that process morphology is the one most suited to gene annotation

Homeosis in the flowers of the Zingiberales

Homeosis has played an important role in the evolution of the flowers of the Zingiberales, especially those of the Ginger Group. In the Zingiberaceae, two members of the outer androecial whorl are replaced by a lip, and two members of the inner androecial whorl are replaced by petaloid staminodes. Most of the androecium of the Costaceae has also been replaced by petaloid structures, and the single fertile stamen is often attached to an enlarged petaloid "filament." The Cannaceae and Marantaceae have one-half of one fertile anther and three to four variously modified staminodes. In contrast, homeosis has played a minor role in floral evolution of the Banana Group. Only in the Heliconiaceae has a stamen been replaced by a staminode. In none of the families of the Zingiberales do the staminodes assume the total "form or character" of any perianth members. Because of this, it is reasonable to extend the definition of homeosis to include replacement by an organ like, but not identical to, some other part of the plant

Calcium distribution and function in the glandular trichomes of Lavandula pinnata L

Calcium distribution during peltate and capitate glandular trichome development in Lavandula pinnata L. was examined with the potassium antimonate precipitation method. In order to establish a role for calcium in the secretory process and elucidate calcium function in the glands, the effects of calcium removal were investigated by treatment with nifedipine (Nif, a calcium channel blocker) and Ethylene glycol-bis (2-aminoethyl ether)-N, N, N9, N9-tetraacetic acid (EGTA, a calcium chelator). Untreated, mature glands accumulate many calcium precipitates in the subcuticular space and adjacent cell wall during secretion. In Nif or EGTA treated plants these precipitates disappear, and the amount of secretory product is drastically reduced. Calcium removal also results in a reduction in gland density, cells with decreased cytoplasmic density, formation of a lax cell wall, abnormal formation of the subcuticular space, thinning of the cuticle, and the presence of multivesicular bodies near the plasma membrane. At the post-secretory stage, calcium precipitates are common on the degenerating organelles. These results support a role for calcium in gland development, secretion, and programmed cell death

The phyllotaxy of Costus (Costaceae)

The spiromonostichous phyllotaxy of Costus, and other Costaceae, is characterized by low divergence angles, often as low as (30°—) 50°. This constrasts with the main series Fibonacci (divergence angles ap-proximating 137.5°) or distichous phyllotaxy found in all other Zingiberales. A morphological and devel-opmental study of three species of Costus revealed a number of facts about this unusual phyllotactic pattern. In C. scaber and C. woodsonii the divergence angles gradually change along a shoot, from 140°-100° in the region of the cataphylls to 60°-45° in the inflorescence. In C. cuspidatus, the divergence angles change from 40°-100° in the cataphyll region to ca. 137° in the inflorescence. In all three species, the cataphylls and foliage leaves have tubular sheaths, while the inflorescence bracts are nonsheathing. Thus, spiromo-nostichy is only loosely correlated with closed leaf sheaths