Tasting the Tree of Life: Development of a Collaborative, Cross-Campus, Science Outreach Meal Event.

Communicating about science with the public can present a number of challenges, from participation to engagement to impact. In an effort to broadly communicate messages regarding biodiversity, evolution, and tree-thinking with the campus community at The College of New Jersey (TCNJ), a public, primarily undergraduate institution, we created a campus-wide, science-themed meal, "Tasting the Tree of Life: Exploring Biodiversity through Cuisine." We created nine meals that incorporated 149 species/ingredients across the Tree of Life. Each meal illustrated a scientific message communicated through interactions with undergraduate biology students, informational signs, and an interactive website. To promote tree-thinking, we reconstructed a phylogeny of all 149 ingredients. In total, 3,262 people attended the meal, and evaluations indicated that participants left with greater appreciation for the biodiversity and evolutionary relatedness of their food. A keynote lecture and a coordinated social media campaign enhanced the scientific messages, and media coverage extended the reach of this event. "Tasting the Tree of Life" highlights the potential of cuisine as a valuable science communication tool.

Pollen structure and development in Nymphaeales: insights into character evolution in an ancient angiosperm lineage.

PREMISE OF THE STUDY: A knowledge of pollen characters in early-diverging angiosperm lineages is essential for understanding pollen evolution and the role of pollen in angiosperm diversification. In this paper, we report and synthesize data on mature pollen and pollen ontogeny from all genera of Nymphaeales within a comparative, phylogenetic context and consider pollen evolution in this early-diverging angiosperm lineage. We describe mature pollen characters for Euryale, Barclaya, and Nymphaea ondinea, taxa for which little to no structural data exist. METHODS: We studied mature pollen for all nymphaealean genera using light, scanning electron, and transmission electron microscopy. We reviewed published reports of nymphaealean pollen to provide a comprehensive discussion of pollen characters in water lilies. KEY RESULTS: Nymphaeales exhibit diversity in key pollen characters, including dispersal unit size, ornamentation, aperture morphology, and tapetum type. All Nymphaeales pollen are tectate-columellate, exhibiting one of two distinct patterns of infratectal ultrastructure-a thick infratectal space with robust columellae or a thin infratectal space with thin columellae. All genera have pollen with a lamellate endexine that becomes compressed in the proximal, but not distal wall. This endexine ultrastructure supports the operculate hypothesis for aperture origin. Nymphaeaceae pollen exhibit a membranous granular layer, which is a synapomorphy of the family. CONCLUSIONS: Variation in pollen characters indicates that significant potential for lability in pollen development was present in Nymphaeales at the time of its divergence from the rest of angiosperms. Structural and ontogenetic data are essential for interpreting pollen characters, such as infratectum and endexine ultrastructure in Nymphaeales.

Development and ecological implications of dormant buds in the high-Paleolaltitude Triassic sphenophyte Spaciinodum (Equisetaceae).

Spaciinodum collinsonii, a Triassic sphenophyte from the central Transantarctic Mountains, Antarctica, is reinterpreted based on new material in order to clarify discrepancies from previous work and to detail the development and ecology of the Spaciinodum plant. Vegetative stems have alternating nodes and internodes, nodes distinguished by a solid diaphragm of tissue, internodes by the presence of vallecular (cortical) and carinal canals, and a hollow pith. Whorls of branches arise immediately above the nodes, alternating with the leaves of the subjacent nodes. Branches develop in the cortex and are anatomically similar to the stems. While Spaciinodum is similar to extant Equisetum, it is distinctive in that its large vallecular canals form a complete ring within the cortex and are separated only by thin fimbrils of tissue. The majority of specimens of Spaciinodum are now believed to be dormant buds with condensed nodes and internodes, with progressively longer internodal regions more basally. More apical portions of buds have cellular internodes because the areas where the canals will form have not yet ruptured from elongation. The abundance of buds and the absence of elongated stems in the permineralized peat deposit suggest that Spaciinodum underwent dormancy during the dark Antarctic winters.

Pollen and anther ontogeny in Cabomba caroliniana (Cabombaceae, Nymphaeales).

Cabomba is a small water lily genus that is native to the New World. Studies of pollen development and associated changes in the anther yield valuable characters for considering the evolution of reproductive biology in seed plants. Here we characterized the complete ontogenetic sequence for pollen in Cabomba caroliniana. Anthers at the microspore mother cell, tetrad, free microspore, and mature pollen grain stages were studied using scanning electron, transmission electron, and light microscopy. Tetragonal and decussate tetrads both occur in C. caroliniana, indicating successive microsporogenesis. The exine is tectate-columellate, and the infratectal columellae are the first exine elements to form, followed by a continuous tectum and a thin foot layer. A lamellate endexine initiates in the early free microspore stage, but becomes compressed in mature grains. Tectal microchannels and sculptural rods also initiate during the early free microspore stage, and significant pollenkitt deposition follows, supporting the hypothesis that these elements function in entomophily. The tapetum is morphologically amoeboid, with migratory tapetal cells directly contacting developing free microspores within the anther locule. Results from this study illustrate the importance of including ontogenetic data in analyzing pollen characters and in developing evolutionary and ecological hypotheses. The new palynological data also emphasize the character plasticity that occurs in basal angiosperms.

Aerodynamics of saccate pollen and its implications for wind pollination.

Pollen grains of many wind-pollinated plants contain 1-3 air-filled bladders, or sacci. Sacci are thought to help orient the pollen grain in the pollination droplet. Sacci also increase surface area of the pollen grain, yet add minimal mass, thereby increasing dispersal distance; however, this aerodynamic hypothesis has not been tested in a published study. Using scanning electron and transmission electron microscopy, mathematical modeling, and the saccate pollen of three extant conifers with structurally different pollen grains (Pinus, Falcatifolium, Dacrydium), we developed a computational model to investigate pollen flight. The model calculates terminal settling velocity based on structural characters of the pollen grain, including lengths, widths, and depths of the main body and sacci; angle of saccus rotation; and thicknesses of the saccus wall, endoreticulations, intine, and exine. The settling speeds predicted by the model were empirically validated by stroboscopic photography. This study is the first to quantitatively demonstrate the adaptive significance of sacci for the aerodynamics of wind pollination. Modeling pollen both with and without sacci indicated that sacci can reduce pollen settling speeds, thereby increasing dispersal distance, with the exception of pollen grains having robust endoreticulations and those with thick saccus walls. Furthermore, because the mathematical model is based on structural characters and error propagation methods show that the model yields valid results when sample sizes are small, the flight dynamics of fossil pollen can be investigated. Several fossils were studied, including bisaccate (Pinus, Pteruchus, Caytonanthus), monosaccate (Gothania), and nonsaccate (Monoletes) pollen types.

Pollen ontogeny in Brasenia (Cabombaceae, Nymphaeales).

Brasenia is a monotypic genus sporadically distributed throughout the Americas, Asia, Australia, and Africa. It is one of eight genera that comprise the two families of Nymphaeales, or water lilies: Cabombaceae (Brasenia, Cabomba) and Nymphaeaceae (Victoria, Euryale, Nymphaea, Ondinea, Barclaya, Nuphar). Evidence from a range of studies indicates that Nymphaeales are among the most primitive angiosperms. Despite their phylogenetic utility, pollen developmental characters are not well known in Brasenia. This paper is the first to describe the complete pollen developmental sequence in Brasenia schreberi. Anthers at the microspore mother cell, tetrad, free microspore, and mature pollen grain stages were studied using combined scanning electron, transmission electron, and light microscopy. Both tetragonal and decussate tetrads have been identified in Brasenia, indicating successive microsporogenesis. The exine is tectate-columellate. The tetrad stage proceeds rapidly, and the infratectal columellae are the first exine elements to form. Development of the tectum and the foot layer is initiated later during the tetrad stage, with the tectum forming discontinuously. The endexine lamellae form during the free microspore stage, and their development varies in the apertural and non-apertural regions of the pollen wall. Degradation of the secretory tapetum also occurs during the free microspore stage. Unlike other water lilies, Brasenia is wind-pollinated, and several pollen characters appear to be correlated with this pollination syndrome. The adaptive significance of these characters, in contrast to those of the fly-pollinated genus Cabomba, has been considered. Brasenia does not produce pollenkitt nor develop tectal microchannels as does Cabomba. Instead, the discontinuity of the tectum reduces the amount of sporopollenin in the wall, which may allow for more effective wind dispersal. The importance of reassessing palynological characters in light of new ontogenetic data and the phylogenetic implications of this reevaluation are also discussed.