Art of Science: All's Fair in Love and War

Jacob Francis, Ph.D., an assistant professor in the Charles E. Schmidt College of Science, studies plants and the animals that help many of them reproduce. His research, which ranges from nectar microbiomes to pollinator decision-making to floral chemistry, has recently turned to South Florida’s flowers.

"This is a really excellent place to study the natural world and how humans are impacting it," he said. "Florida is a unique place with endemic species that cannot exist anywhere else. There is no shortage of plants, introduced from around the world, that are changing our native ecosystems. That kind of locality, and its complex interactions with human society, are what makes the world a beautiful place to be."

This image captures a dark-field view of the stigma of Mexican clover (Richardia grandiflora), a weedy, non-native plant commonly found on South Florida lawns. The stigma is part of the floral organ responsible for receiving pollen and for female reproductive success. At the center of the stigma, bright green calcium oxalate crystals are arranged as large raphide bundles (groups of needle-like formations) and druses (smaller, crystal clusters with sharp protrusions) that refract light in a striking display. These crystals, composed of the same compound as kidney stones, are thought to be produced by many plants as a metabolic byproduct. They can possibly deter chewing herbivores. One current project in the Francis Pollination Ecology Lab investigates the ecological consequences of variation in these crystal structures across tissues and populations of R. grandiflora.

On the outer surface of the stigma, magenta pollen grains, stained with Basic Fuchsin for contrast, stand out sharply. Some grains have already germinated, sending pollen tubes toward the ovules to produce seeds. Each pollen grain carries male genetic material. The successful journey of pollen from the stigma to an ovule is crucial for the reproductive success of the plant’s male component. In this image, many pollen grains compete to germinate, release their genetic contents, and sire the next generation.

Francis achieved the clarity and depth in this image with a focus stack of nine images. His photograph reveals the intricate details of R. grandiflora’s reproductive and defensive strategies at a microscopic level.