About This Project

How does a seed begin? In Ephedra, a desert shrub from an ancient, unusual lineage of seed plants, the first steps of seed formation are almost unknown. I will collect young seed cones in eastern California, image seed meristem initiation in 3D with confocal microscopy, and sequence RNA from the same stages to find the genes active as seeds begin. The result: a reference map of seed initiation in Ephedra, a new comparison with cones and flowers to help explain how seed-making structures evolved.

Ask the Scientists

What is the context of this research?

My work on seed development across gymnosperms led me to a simple question with no clear answer: how does a seed begin? In flowering plants, the genes and hormones that start reproductive structures at the shoot meristem are well studied. Far less is known in gymnosperms, and almost nothing in Gnetales, a small lineage whose position among seed plants is still debated. Ephedra, a desert shrub of the Gnetales, forms its seed cones in a short window in late winter, making it ideal for tracking this first step in wild plants.

My question is: how and when do seed-forming meristems initiate in Ephedra, and which genes are active as they do? I will collect seed cones at successive early stages in eastern California, image them in 3D with confocal microscopy, and sequence RNA from the same stages. I expect to identify when and where seed meristems first appear and a set of genes linked to their initiation, giving a reference to compare with conifers and flowering plants.

What is the significance of this project?

Seeds are one of the great innovations of plant evolution. They allowed plants to colonize all ecosystems, and today they feed most of the world. Yet the very first step of making a seed, when a small group of cells at a shoot tip switches from making stems to making a seed, has been studied in only a handful of plants, mostly flowering plants grown in the lab.

Ephedra gives us a rare chance to see this step in a completely different branch of the seed plant tree. It belongs to the Gnetales, a small and strange group of gymnosperms whose place among seed plants has puzzled botanists for a long time. No one has yet followed how its seeds begin cell by cell while also reading which genes are active. By pairing 3D imaging with gene expression from wild plants, this project will create a reference that other scientists can compare with pines and flowers, helping us understand how evolution built the structures that make seeds, and how an ancient lineage has survived for so long.

What are the goals of the project?

My overall goal is to build a detailed map of how seeds begin in Ephedra, a desert shrub from an ancient and unusual lineage of seed plants. First, between January and February, I will make a series of short trips to eastern California to collect young seed cones from the same wild populations, capturing successive early stages as they unfold. After each trip, I will bring the samples back to the lab to process them while they are fresh. Next, I will use confocal microscopy to image these young cones in 3D, cell by cell, to see exactly when and where the seed-forming meristems appear and how they take shape. In parallel, tissue from the same stages will be sequenced to reveal which genes are switched on as a seed begins. Combining what the cells look like with the genes they express will give a complete picture of seed initiation. I expect to finish imaging and analysis by the end of the year, and I plan to share the results openly and publish them.