From sweet and floral to skunky and funky scents, the fragrance of a flower is unique. Certain floral scents are hypothesized to attract pollinators, defend against herbivores or act as a mode of communication between plants. Describing a plant as sweet or skunky is a great start, but with the right training and tools, botanists can more deeply understand the exact chemical reasons as to why a plant smells the way it does. </p> Many botanists are passionate about understanding the biochemistry responsible for plant aromatics and incorporating it into their research, like me! This past month, I took a trip to Cornell University to train with floral scent expert Robert Raguso. Using the Arkansas Valley evening-primrose (Oenothera harringtonii</em>) from the greenhouse, we practiced collecting the floral scent. To do so we needed four elements: a plant of interest, a headspace, an air pump and a method of capture. Together, these tools allow us to concentrate molecules and then move them into our method of capture to take back to the lab. If done carefully and correctly, this data collection can be done without causing any harm to the plant of interest. </p> Once back in the lab, we inject our floral scent cocktail into a machine called a gas chromatography-mass spectrometer (GC-MS), a tool which separates and breaks down samples to identify substances and determine their chemical structures and quantities. These are highly specialized instruments capable of determining even the most cryptic of compounds. After injection, the floral compounds travel through a glass column, by force of an inert gas. Inside this column, compounds are separated from one another. As the isolated compounds exit the other end of the column, they are ionized by a laser beam where their mass to charge ratio (m/z) is determined. We are left with both a chromatogram and a mass spectrum; software is then used to determine which compounds are present in our sample. </p> In the case of Oenothera harringtonii</em>, we identified several dominant compounds, particularly a compound called linalool. Linalool, an acyclic monoterpene tertiary alcohol, is known to manifest as a woody, floral scent in several notable plant genera, such as Coriandrum </em>(known for coriander and cilantro) and Lavandula </em>(known for lavender). Oenothera harringtonii </em>is a night-blooming angiosperm that requires the visitation of hawkmoths for successful pollination. Linalool is observed to attract moth visitors, while simultaneously being a deterrent of other herbivorous invertebrates. </p> Whether studying the delicate emissions of alpine wildflowers or analyzing the complex aromatics of cultivated blooms, each volatile molecule we identify tells a worthwhile chemical story. </p> Special thanks to Robert Raguso and Cornell University for taking the time to share their knowledge about floral biochemistry. Learn more about Professor Raguso’s work</a>.</p> This article was contributed by graduate student Ashlee Kerber</strong>.</em> </p>
We’ve been getting a lot of questions about the unusual weather and early blooms this winter, so we decided to check in with one of our horticulturists, Laura Swain, to get the scoop.</p> Why are we seeing early blooms?</h4> We are currently experiencing the warmest and driest winter on record with an average temperature of 43 degrees! Many of our beloved early season plants have evolved in more temperate regions of the world. In the late summer and fall, all plants form buds – or tiny packets of densely stored energy for fast growth in the spring. These buds are typically covered in modified leaves, called bud scales, that keep the buds warm and cozy during winter months. Some plants have already met their dormancy requirements, and the warm days (and nights!) trick the plants into thinking it’s spring. </p> Is this bad for the plants?</h4> The risk is that here in Colorado, we will likely get another deep cold spell before winter is over. When this happens, if plants have already opened those bud scales, they become susceptible to winter burn and dieback. This is rarely enough to kill a plant. They may need some extra pruning in spring. This applies primarily to woody trees and shrubs. For herbaceous perennials, plants may expend some extra energy with early winter growth and subsequent dieback but typically have enough stored energy in their roots to carry on when spring finally arrives. </p> While early flowering itself is not detrimental to overall plant health, there is </em>another risk we should be aware of: what is happening below ground. During winter dormancy, plants stop growing above ground shoots, but roots are still busy growing and storing energy. When winters are very dry and warm, many root systems (and bulbs) can suffer. This is especially concerning for newly planted trees, shrubs, perennials and bulbs. </p>
Every other year, the Society for Ecological Restoration</a> hosts an international conference convening restoration researchers and practitioners from around the globe. This year, the conference was held in Denver, and we had the opportunity to not only attend the conference but share the Gardens with participants. Staff from across several departments attended and presented our ongoing research. Our engagement started well before the conference -- we participated in planning and also grew native plants to use for display at the conference that were then planted at the Plains Conservation Center</a> after the meeting. </p> I partnered with colleagues from Naples Botanical Garden, North Carolina Botanical Garden and Chicago Botanic Garden to present on the role of botanic gardens in supporting the native seed supply for restoration. April Goebl presented her work on increased within-species genetic diversity for restoration. Graduate student Meredith Prentice also presented a poster on her thesis work relating post-fire plant communities. </p> At the beginning of the conference, we led a field trip for conference participants to Chatfield Farms</a> to learn about our restoration efforts across scales. We highlighted the experiments we are doing that help inform restoration from backyards to larger open spaces and consider genes to community level processes. We were able to show a multi-year small-scale prairie restoration and several experiments assessing different seeding and planting techniques, local adaptation for seed sourcing, community composition, and site preparation. </p> The best part of attending these types of events is learning cutting edge research and new techniques and meeting with colleagues new and old in person. It is truly invigorating to feel connected by our shared work and mission and to use the lessons learned to improve what we are doing. This year was particularly rewarding because there were so many researchers from other botanic gardens from around the world. I was able to organize an impromptu dinner with most of them, and we not only had a lovely evening connecting over shared issues and opportunities, but we left with some concrete ways we can continue to partner and engage the botanic garden community in restoration even more.</p>
