Category Archives: Botany and Plant Pathology

You don’t look your age: pruning young forests to mimic old-growth forest

“I’m always looking at the age of the forest, looking for fish, assessing the light levels. Once you’ve studied it, you can’t ignore it.” Allison Swartz, a PhD student in the Forest Ecosystems and Society program in the College of Forestry at Oregon State, is in the midst of a multi-year study on forest stream ecosystems. “My work focuses on canopy structure—how the forest age and structure influences life in streams,” says Allison. “People are always shocked at how many organisms live in such a small section of stream. So much life in there, but you don’t realize it when you’re walking nearby on the trail.”

Three scientists holding large nets stand in a rocky forest stream. One wears a backpack with cable coming out of it.
No, that’s not a Ghostbuster backpack! Here, Allison is using an electrofishing device that stuns fish just long enough for them to be scooped up, measured, and released. From left to right: Allison Swartz, Cedar Mackaness, Alvaro Cortes. Photo credit: Dana Warren

Following a timber harvest, there is a big increase in the amount of light reaching the forest floor. The increase in light also results in an increase in stream temperatures. Fish such as salmon and trout, which prefer cold water, are very sensitive to temperature changes. Since these fish are commercially and recreationally important, Oregon’s water quality regulations include strict requirements for maintaining stream temperatures. As a result, buffer areas of uncut forest are left around streams during timber harvests. These buffer areas, like much of the forests in the Pacific Northwest, and in the United States in general, can be characterized as being in a state of regeneration. Dense, regenerating stands of trees from 20-90 years old, are sometimes called second-growth forest. These forests tend to let less light through than an old growth forest does. Allison’s work focuses on how life in streams responds to differences in forest growth stage.

A Pacific giant salamander – a top-level stream predator and common resident of Oregon’s forest streams. Photo credit Allison Swartz.

The definition of the term old-growth forest depends on which expert you ask, and there is even less agreement on the concept of second-growth forest. Nevertheless, broadly speaking an old-growth forest has a wide range of tree species, ages, and sizes, including both living and dead trees, and a complex canopy structure. Openings in the canopy from fallen trees allow a greater variety of plant species to be established, some of which can only take root under gaps in the canopy but which can persist after the gap in the canopy is filled with new trees. The tightly-packed canopy limits the amount of light that can reach the forest floor, including the surface of the streams that Allison studies.

Forest stream near Yellowbottom Recreation Area, Oregon. Credit: Daniel Watkins

Allison’s research project is focused on six streams in the MacKenzie river basin, which includes private land owned by the Weyerhaeuser company, parts of the Willamette National Forest, and federal land. At some of these sites, after an initial survey, gaps were cut into the forest canopy to mimic light availability in an old growth forest. Sites with cut canopies were paired with uncut areas along the same stream. The daily ebb-and-flow of aquatic species is monitored by measuring the oxygen content of the water. The aquatic and terrestrial ecosystems have mainly been studied separately, she explained, but the linkages between these systems are complex. Measurements of vertebrate species are carried out using electrofishing techniques. “We do vertebrate surveys which infludes a few species of fish and Pacific giant salamanders. We measure and weight them and then return them to the stream,” Allison explained.

Measuring cutthroat trout. Photo credit Allison Swartz.

Over the last few years, Allison has spent three months of the summer living and working at one of her research sites, the HJ Andrews Experimental Forest. “We didn’t have much in terms of internet the first few years, so you connect with people and with the environment more,” Allison said. 

Allison never expected to be in a college of forestry. Her background is in hydrology, and she spent some time working for the United States Geological Survey before beginning graduate work. She has enjoyed being part of a research area with such direct policy and management impacts. “We all use wood, all the time, for everything. So we can’t deny that we need this as a resource,” says Allison. “It’s great that we’re looking at ways to manage this the best we can—to make a balance for everybody.”

The Sights and Sounds of Purple Martins

The aesthetic beauty and spiritual connectivity the Native Americans have to the Purple Martin is undeniably strong, it’s no wonder the general public have embraced this special bird and encouraged their presence by adding nest boxes in their backyards. However, it’s this strong embrace in urbanized areas that could be stifling the ability for these animals to find and utilize forest habitats that could be spelling trouble for the birds’ future success. Currently the Purple Martin is listed in the state of Oregon as a “Sensitive-Critical Species” and our guest Lorelle Sherman, a 2nd year Masters student in the Department of Forest Ecosystems and Society, is going to help us understand how humans have possibly altered their natural tree-nesting behavior of the Purple Martin population.

Male Purple Martins who are the largest birds in the Swallow group. Photos curtsey of the Cornell Lab of Ornithology

These are birds with an eye-popping iridescent blue-purple body, sleek black wings with a forked tail that aid in its magnificent maneuverability allowing them to fly at speeds of 45 mph or faster. The Purple Martins often nest in groups to help protect each other from predators, their colonial personalities help generate southing chitchat between birds, and they’re very happy to live in artificial nest boxes. So much so that on the east coast of the US they live almost exclusively in bird boxes. Therein lies the problem – these birds are common on the east coast because they completely depend on habitat provided to them by humans; some researchers worry they have lost the generational knowledge of going to the forest to find suitable homes. Conversely, along the west coast of the US they generally utilize cavities in snags (standing dead trees) as their nesting site, but adding backyard bird boxes for the Purple Martin are becoming more common.

Purple Martin in a natural tree snag (standing dead tree) habitat.

Purple Martins are aerial insectivores meaning they only eat insects while they are in flight. Here is a classic yummy meal for the bird.

Although humans are supplementing places for these birds to nest, high quality habitat in forested areas are shrinking because our natural ecosystems are in peril. Purple Martins have historically depended on wildfires to clear open areas for better hunting grounds, but with the onset of fire-suppression efforts across the west these birds are more reliant on clearcuts typical of industrial forestlands. Couple these regional patterns with the recent global finding that flying insect populations (Martins’ food source is exclusively from eating insects while in-flight) in the tropics are expected to decline as much as 20%, and from 1989-2016 German nature preserves have documented a 75% decline flying insects biomass. It’s no surprise that aerial insectivores being the most rapidly declining group of birds in North America. If scientists are to better understand avian populations, the habitat qualities and the relative availability of food necessary for their survival must be assessed simultaneously.

Lorelle is banding a Purple Martin near a wetland to be able to track it’s movements in the future

Lorelle will help us untangle the effects of declining insect populations, possibly driven by a warming climate, and overlay those links with how humans on the west coast are putting up more artificial bird boxes making it easier to for birds to disregard forests as potential habitat all together. She is slowly uncovering the hidden elements of these critical birds by studying the food sources in two different habitats, an upland forest and along waterways with artificial bird boxes, and the birds’ willingness to seek out ideal habitat. Lorelle has grown up infatuated by birds her whole life, often running away from home just to sit underneath a tree to observe her flying friends overhead. At the age of eight her parents got her binoculars to cultivate her love of birds that she carried through her undergraduate research experiences in Vermont studying Double-crested Cormorants and Great Horned Owls. After a landing a dream job at a non-profit focusing on environmental education and green infrastructure in Pennsylvania she decided it was a good time to return to school to pursue a graduate degree. She originally moved to Oregon to work at the Bandon National Wildlife Preserve, but is now a Masters Student with Dr. Joan Hagar while continuing her outreach activities volunteering for birding festivals such as the Oregon Shorebird Festival and the Birding & Blue Festivals. In her free time you can find Lorelle running away from the office and searching for mushrooms, wild edibles, or other elusive birds.

Join us Sunday October 21st at 7PM on 88.7FM, or listen live, to learn more about Purple Martins and how these birds are intimately tied to the natural ecosystems around us as well as the urbanized spaces we occupy together.

Lorelle at the age of 8 continuing her passion for the outdoors with with her grandfather; note the binoculars which were one of the many steps to foster her love for birds.

Secrets of the Black Cottonwood

Ryan cultivated his interest in plants at a young age while checking wheat fields with his dad on the family farm near Beltrami, MN.

Growing up on a family farm in North Dakota, Ryan Lenz loved learning about wheat – specifically the things that made wheat varieties different. Why were some taller or shorter than others? Why did some have more protein? After gaining skills in molecular biology at North Dakota State University with a Bachelor of Science in Biotechnology, Ryan interned with a biotech company where he was finally able to make the connection between wheat varieties and the genes that make them different. This experience sparked his interest and led him to earn a Master’s degree in Plant Sciences at his alma mater and eventually brought him to OSU’s Department of Botany & Plant Pathology to study host-pathogen interactions as a PhD student with Dr. Jared LeBoldus.

Using black cottonwood (Populus trichocarpa) – a native tree to the western US – Ryan is working to reveal the genes responsible for making woody plants susceptible to fungal disease and those that give the fungus the ability to infect trees. The fungus of interest, Sphaerulina musiva, causes leaf spot and stem canker on cottonwood trees – the latter disease being more severe as it girdles the trees and causes the tops to break off.

Ryan tending to his tissue culture plants in the LeBoldus Lab.

The fungal pathogen was first found in the eastern United States in association with the more resistant eastern cottonwood (Populus deltoides), but has worked its way westward putting the susceptible black cottonwood at risk. This fast-growing cottonwood is a foundation species in riparian areas and provides erosion control. Not only are these trees important ecologically, they are also important in forest agriculture for their uses in making pulp for paper, biofuels, building materials, windbreaks, and for providing shade.

Ryan and his wife, Rebecca, enjoying the beautiful Pacific Northwest.

To learn how the tree and fungus interact, Ryan employs advanced molecular techniques like the CRISPR-Cas9 system to edit genes. To put it simply, he tries to find the important information in the plant and fungus by making changes in the genetic code and then seeing if it has a downstream effect. The implication of his work has two sides. On one hand, Ryan is trying to provide cottonwood breeders with insight to make a more resistant tree to be grown in the western US. While on the other hand, he is working to establish the black cottonwood as a model system for other woody hosts susceptible to necrotrophic fungi – those that feed on dead tissue. As a model system, the secrets of the black cottonwood would be unveiled, providing a blueprint of valuable information that could be applied to other woody trees.

 

One day, Ryan hopes to move back to the Midwest to be a plant researcher near his family’s farm.

Join us on Sunday, November 5, at 7 PM on KBVR Corvallis 88.7 FM or stream live to learn more about Ryan’s love for plant genetics and his journey to graduate school.

You can download Ryan’s iTunes’ Podcast Episode!

Tracing Goethe’s influence on botany and plant morphology

As a History of Science PhD student in the School of History, Philosophy, and Religion, Andy Hahn studies how botanists and plant morphologists in the 20th century were influenced by Goethe, a famed German writer and naturalist during the 19th century. Goethe is well known for his rendition of Faust, as well as his novel, The Sorrows of Young Werther. Although historians and philosophers have studied Goethe extensively, his influence on subsequent generations of botanists and plant morphologists has not been fully explored. Goethe wrote a book called Metamorphosis of Plants, which provided early foundational insight into morphology, the study of plant structure and appearance of plant features such as leaves and petals. For his PhD work, Andy has visited institutional archives in Switzerland, England, and Scotland to study the letters and writings of 20th century botanists and other scientists influenced by Goethe’s science.

Goethe’s science was characterized by taking account appearance and structure of plants as a whole entity, as opposed to focusing only specific parts of the plant, a method employed in the taxonomy of Linnaeus, a prominent 18th century natural historian. As the 19th century progressed, Goethe’s approach towards morphology was well-integrated in botanical science in Germany, France, and England. However, the rise of Darwinism, genetics, and experimental methods in the late 19th and early 20th centuries was accompanied by a decreased role for Goethe’s style of morphology. In the early 20th century, plant morphologist community split into two groups: new morphology based in Darwinian thought, and old morphology based in Goethe’s principles. The influence of Goethe’s writing can be seen among botanists in the 20th century, including Agnes Arber, a plant morphologist who translated Goethe’s Metamorphosis of Plants into English.

Andy was introduced to Goethe’s scientific work as he continued to follow his interests that arose from his as an undergraduate in philosophy. He appreciated Goethe’s and current Goethean scientists’ approach to plant morphology as a means to understand the natural world. By visualizing a plant through the course of its life, he was able to develop a stronger connection to the natural world, awakening his own senses by meditating on the form of plants. Andy found himself wondering what happened to the ideas of Goethe, and why Goethe’s ideas weren’t recognized more commonly in biological education. He became interested in philosophical questions surrounding why we think the way we do, as well as the accumulation of knowledge; in particular, how we produce scientific knowledge, and how we can be certain about it. During his Masters studies at OSU, Andy first began researching the botanical work of Goethe, and has continued to study the influence of Goethe on 20th century botanists for his PhD work. Following completion of his graduate studies, Andy would like to teach history of science at the university level and pursue science writing.

To hear more from Andy about the influence of Goethe’s science on botany and plant morphologists, tune in to Inspiration Dissemination on Sunday, October 22 at 7pm on 88.7 KBVR Corvallis. Or stream it online here!

You can download Andy’s iTunes Podcast Episode!

The Grape Depression: Powdery Mildew in Willamette Valley Vineyards

Brent at the Foliar Pathology Lab research vineyard where the small plot field trials in his project were conducted.

Viticulture is the science, production, and study of grapes, and when growing grapes for wine both quantity and quality matter. One challenge facing farmers in the Willamette Valley is a plant pathogen: grape powdery mildew. This pathogen can live in a field year-round and emerges to infect grape leaves, flowers and fruits annually. Grape plants infected with powdery mildew suffer low berry yields and mildew may affect the taste of wine. In the Willamette Valley, where vineyards abundant, grape powdery mildew is a big problem. Brent Warneke, a Master’s student in the department of Botany and Plant Pathology, is studying the effect of fungicide application timing on the reduction in severity of powdery mildew on grapes, and he is our guest on Inspiration Dissemination this week.

Moldy Grapes

A grape bunch severely infected with powdery mildew. Note the berry cracking, powdery appearance, and poor color accumulation.

Brent works at the USDA Horticultural Crops Research Lab with Walt Mahaffee, and his research tests the effect of fungicide application timing on grape powdery mildew control. Timing fungicide applications is especially crucial during the one to three-week window of grapevine flowering. Optimal fungicide application timing can slow the mildew epidemic allowing grape berries to mature and become less susceptible to powdery mildew. Across the Willamette Valley, fungicide application to grapes is a well-known prevention solution for powdery mildew, but less is known about the best fungicide to use and when to spray plants during berry development. The findings of his research are now being validated at a larger scale in commercial vineyards. In the lab, Brent is also studying the mobility of fungicide “through the grapevine,” from tissue to tissue through the air and xylem, and Brent is helping with a project to identify strains of mildew resistant to commonly used fungicides.

 

The Grape State of Colorado 

Brent with a harvest of varnish conk (Ganoderma oregonense), Lobster mushroom (Hypomyces lactifluorum).

Brent hails from Colorado where he spent his early years outside gardening, snowboarding, and hiking. During undergrad at Colorado State University (CSU), Brent majored in Horticulture and held research positions at the Center for Agricultural Resources Research and the Bioenergy Lab. Among his many projects during undergrad, Brent completed a senior thesis project, under the direction of Dr. Courtney Jahn, developing a LAMP-PCR to diagnose Canada thistle rust on infected plants that were not displaying symptoms.

Wine Not?

While at CSU, Brent also began studying viticulture. He liked the challenge and complexity of growing grapes for wine. Brent chose to pursue graduate school at Oregon State because his current program blends plant pathology with viticulture. He’s happy with his decision because Oregon is similar to Colorado for outdoor recreation, not to mention its world class Pinot Noir!

Hear more from Brent this Sunday September, 10 at 7PM on KBVR Corvallis, 88.7FM! Not a local listener? Not sweat! Stream the show live.

Brent on top of South Sister (10,363 ft). Middle and north sister can be seen in the immediate background. In the far background the small peak to the left without snow is Mount Washington , then Mount Jefferson behind north sister and Mount Hood in the background to the right of North Sister.

Unearthing the Unseen: Identifying drivers of fungal diversity in Panamanian rainforests

When our roommates or family members get sick, we try to keep our distance and avoid catching their illness. Plants get ‘sick’ too, and in the natural world, this may actually explain the coexistence and diversity of plant species that we see.

Coexistence

Species coexistence relies on competition between individuals of the same species being larger than competition between individuals of different species. Competition between individuals of the same species must be large enough to keep any species from taking over and outcompeting all other species in the community. However, more recent work has highlighted the role of natural pathogens. Stable coexistence of many species may be favored if individuals of one species cannot live in close proximity to each other due to disease.

Plant Pathogens and Biodiversity

View looking south from the canopy tower at the Gamboa Rainforest Resort over the confluence of the Panama Canal and the Chagres River near Gamboa, Panama.

For example, picture a crowded forest with many adult trees of the same species releasing wind-dispersed seeds (like the helicoptering seeds of a maple). Very few, if any, of the seeds that fall near to the adult trees will germinate and reach maturity. As you walk away from the clump of adult trees, you will begin to find more germinated seeds that reach maturity (Augspurger 1983). These seeds are farther from tough competitors of the same species (adult trees) and are away from the plant pathogens that may be living in the adult root system. In our hypothetical forest, the plant pathogens that feed on young maples are keeping maple from dominating the forest, allowing other species that aren’t affected by the pathogen to thrive; in this way, plant pathogens play a role in the maintenance of biodiversity.

Drivers of Biodiversity

Our guest this week, Tyler Schappe, studies interactions among plants and fungi in the Neotropical forests of Panama. Tyler is broadly interested in what drives the maintenance and diversity of fungal communities, and how this, in turn, can affect tree communities. Tyler spent the summer of 2015 collecting 75 soil cores from three forest plots in Panama. Using DNA sequencing with universal genetic markers, he was then able to identify the fungi within the soil cores to species and functional group (decomposers, pathogens, plant mutualists, etc.). So far, Tyler has found that tree communities and soil nutrients affect the composition and diversity of fungal guilds differently. As expected, guilds that form mutualistic relationships with trees are more strongly correlated with plant communities. Interestingly, soil properties influence the species composition of all fungal guilds, including plant pathogens, pointing to the mediating role of soils as an abiotic filter. Overall, Tyler’s results, along with other research, show that soil fungal communities are an integral component of the plant-soil relationship since they are driven by, and can affect, both. Together, plants, soil, and fungi form a tightly connected three-way relationship, and wanting to understand one of them means having to study all three together.

Tyler’s work with fungal communities in Panama sheds light on belowground interactions and their implications for plant ecology. His research is one piece of evidence that may help us to understand why there are so many plant species, how they coexist, and why some species are common and some are rare. Are plant pathogens significant contributors to species richness and biodiversity? If so, what modulates plant pathogens, and how can that indirectly affect tree communities? To find out more about Tyler’s work check out these two sources from the Journal of Ecology and Science.

Spend sugar to make sugar

Stand of bur oak trees in a remnant oak savanna at Pheasant Branch Conservancy near Middleton, WI in early winter.

At a young age, Tyler began to realize how connected the world was and how plants and animals function in an ecosystem. The functioning of organisms and of ecosystems came into focus for him while in college at University of Wisconsin-Madison. He took a course in plant ecology from Dr. Tom Givnish who described plants in terms of economic trade-offs. For example, energy invested by plants in vertical growth cannot be invested in defense or reproduction; different allocations of resources can be more or less advantageous in different environments. Tyler decided to pursue graduate school at Oregon State while completing a fellowship with the Smithsonian Tropical Research Institute in Panama, where he met his current advisor, Andy Jones.

Tyler is defending his Master’s thesis August, 29 2017!  We are glad he can make time to talk with us on Inspiration Dissemination this Sunday August, 13 at 7 pm. Not a local listener? Stream the show live!

Ways and Means: Attitudes Toward Methods of Restoring American Chestnut Trees

“The Christmas Song” or “Chestnuts Roasting on an Open Fire” by Bob Wells and Mel Tormé is an iconic song in American culture, but most Americans will never experience a chestnut roast (at least not with American chestnuts).

A mighty blight

The American chestnut was a widespread North American native tree that covered nearly 200,000 miles of Appalachian forest. In 1904, the American chestnut trees in the Bronx Zoo were dying from a then unknown disease, Chestnut Blight. In the next forty years, Chestnut Blight spread across the estimated 4 billion American chestnut trees. Now American Chestnut trees are seen only as giant stumps, juveniles never reaching maturity, and rarely, adult fruit-bearing trees.

Since the decline of the American chestnut, Appalachian forests have changed. Chestnuts have been replaced by oaks, and it is likely that many organisms that relied on the chestnut trees for food or shelter have had to adapt to new conditions or have been displaced. The loss of the chestnut also led to the loss of financial income for many Appalachian people. In addition to chestnuts as a food source, the American chestnut provided decay resistant timber and tannins for tanning hide. The American chestnut and its decline is remembered through oral and written history. Members of older generations from Appalachia tell stories of enormous trees and later forests of white wooden chestnut skeletons.

Restoring the chestnut

Josh skiing in the mountains of Big Sky, Montana.

The restoration of the chestnut is an active project that faces many challenges. First, few Americans have seen an American chestnut tree, and few are familiar with their decline via Chestnut Blight. Since the restoration of the American chestnut would require policy changes and action across 200,000 miles, spanning multiple state governments, it is necessary to assess the extent the public might disfavor or favor this restoration. Our guest this week,Josh Petit from Forest Ecosystems and Society, is seeking to understand the attitudes of Americans toward the chestnut restoration. In particular, Josh is surveying a sample of the US population to compare attitudes toward a controversial method of chestnut restoration,  the use of genetic engineering.

Ways and Means

You may be familiar with genetic engineering to modify the genome of an organism to achieve a specific goal. Many of the crops we eat have in some way been modified to aid harvest, growth, and/or resistance to pests and disease. The methods for restoring the American chestnut are:

  • Selective breeding with related, blight-resistant Asian chestnuts
  • Modifying the genome of American chestnuts with Asian or other related chestnut genes (cisgenics)
  • Modifying the genome of American chestnuts with foreign genes or genes from wheat (transgenics)

Josh conducting research during a study abroad program in tropical North Queensland, Australia.

It is important to assess the attitudes of the public to transgenics because the introduction of  genes from wheat has been the most successful method at enhancing resistance toward chestnut blight. Recently, negative media has led to the misunderstanding that genetically modified organisms (GMOs) have adverse effects on consumers (humans) and ecosystems. However, these claims are not based in sound science and have been refuted. Although GMOs are being supported as alternatives to crop and forest species extinction, ultimately chestnut restoration relies on majority vote in favor or against a specific strategy. Thus, assessing attitudes toward restoration methods is tantamount to restoration efforts.

The Guy for the Job

A native of Ohio, Josh Petit attended Xavier University and majored in Political Science. He credits a Semester at Sea for broadening his world view and exposing him to different cultures. He learned that culture is important in all aspects of daily life. In retrospect, perhaps it is no surprise that he is currently studying an iconic tree and how culture has driven attitudes toward its restoration.

Josh participating in a Fijian traditional village celebration and homestay–taking turns playing guitar.

Josh became interested in ecology, biology, and the interface of the two with humans while working for Q4 International Marketing an ecotourism company in Panama. This lead him to pursue a Master’s in Natural Resources with a marine ecology focus from Virginia Tech. However, his most recent work withOregon Parks and Recreation Department lead him to pursue a PhD at Oregon State University. With the State Parks, Josh conducted surveys in Oregon Parks and sought to connect behavior, impacts, and social science to ecology and recreation. Now at Oregon State University, Josh is working with Mark Needham andGlenn Howe to understand the drivers of attitudes toward using biotechnologies for restoring American chestnut trees.

Hear more about Josh’s research and his journey to now this week on Inspiration Dissemination. Tune in to KBVR Corvallis 88.7FM on Sunday July, 30 at 7 pm, or live stream the show.

Heliconia: plants with personality

Orange-hatted Dusty Gannon’ (my hummingbird name) visiting Heliconia tortuosa

In the Department of Botany and Plant Pathology, first year graduate student Dusty Gannon is studying how Heliconia tortuosa, a tropical plant with long, tubular flowers and vividly-colored bracts (modified leaves that house the flowers), maintains its unique relationship with pollinating hummingbirds. Although hummingbirds universally love nectar, they have diverged into a few distinct functional groups that are characterized by behavior: traplining hummingbirds repeatedly and circuitously visit flowers, often traveling long distances, while territorial hummingbirds are aggressively possessive of flowers in a home range. It turns out that Heliconia tortuosa is picky about which of these groups contributes to its pollination, and preferentially accepts pollen from traplining hummingbirds, specifically those featuring a long, curved bill. Presumably, their bill shape facilitates maximal nectar extraction which is used as a cue by the plant to become receptive to pollen.  Many hummingbirds visit the Heliconia tortuosa flower, but few induce pollination because of the straight shape of their bill. The shape and size of the Heliconia tortuosa flower in relation to the shape and size of the beak of the pollinator hummingbird constitutes the emergence of a complex plant behavior.

Heliconia wagneriana

Heliconia wagneriana

 

 

 

 

 

 

 

 

 

Dusty’s research is focused on trying to understand how Heliconia tortuosa evolved the capacity to recognize and preferentially invest in pollination by certain pollinator hummingbirds. His work consists of testing for ‘pollinator recognition’ of pollinators across a select subset of species across the Heliconia genus, comprised of 200-250 species, and subsequently using molecular techniques to infer the presence or absence of pollinator recognition across
 the family. Among these several hundred different species of Heliconia, the flowers are morphologically distinct and vary in size from short to long,  straight to curved (even up to a 90-degree angle!). Dusty’s objective is to determine if pollinator recognition is a common trait among morphologically distinct Heliconia species, and uncover the evolutionary significance of this cryptic specialization. While conducting fieldwork at Las Cruces Biological Station in Costa Rica, which featured a garden full of Heliconia, Dusty collected over 1,000 styles (the female reproductive organ in flowering plants) to assay pollen-tube growth rates across various treatments by epi-fluorescence microscopy back at OSU.

Tropical montane forest

Unraveling the tangled evolutionary biology of plants and pollinators is critical for understanding how the loss of certain pollinators might impact plant pollination. If a flower is visited by a variety of different pollinators, the loss of one pollinator might not seem like a big deal. However, if only a small number of the total number of pollinators visiting the flower are capable of inducing pollination, the loss of a true pollinator might be devastating for a plant’s ability to reproduce.

A sample of the morphological diversity in Heliconia flowers

As an undergrad at Colorado State University, Dusty studied Ecosystem Science, which consisted of learning about how nutrients and energy flow through an ecosystem. Dusty cites his high school AP Biology teacher as having a major influence on his desire to study science in college. During the first week of his freshman year, Dusty applied to work in a lab doing DNA barcoding; over the span of 4 years, he conducted over 10,000 PCR reactions! Following completion of his undergrad, Dusty planned to climb mountains in South America for a year, but unexpected circumstances expedited his enrollment in graduate school at OSU to pursue research related to pollinator recognition. Following completion of graduate school, Dusty would like to continue in academia as a professor, and possibly open a bread shop featuring a wood-fired oven, equipped with statistical models to ensure a perfect loaf of bread.

Join us on Sunday May 21st at 7PM on KBVR Corvallis 88.7FM or stream live to hear more about Dusty’s pollinator recognition research and journey through graduate school.

Keeping Oregon Forests Green: What Swiss Needle Cast Disease is Teaching Us About Forestry

I’ll never forget driving through the steep and windy I5 corridor of the Klamath Mountains when I moved to Oregon. Wet roads bordered by thick fog with protruding trees that were lusciously green. Very, very green. This concept of ‘Keeping Oregon Green’ started as a fire prevention act, and Oregon’s color is a quality that visitors and residents adore. Unfortunately there is sleeping giant that is gaining momentum, slowly turning Oregon’s forests from green to yellow with an eventual needle fall of the iconic state tree. This color change is from a microscopic fungus that all Douglas-fir trees have around the world, but for some reason it’s only harming the trees along the Oregon coast range. Our guest, a 4th year PhD student Patrick Bennett, is peeling away the layers of complexity to reveal why Oregon’s green forests are dwindling.

Aerial view of Douglas-fir stand with Swiss needle cast near Tillamook, Oregon. Chlorotic (yellow) foliage is a major symptom of the disease.

Douglas-fir needles with pseudothecia (fruiting bodies) of the fungus (Phaeocryptopus gaeumannii) emerging from the stomata.

It is estimated that Swiss Needle Cast disease is affecting nearly 1,000,000 acres in Oregon and Washington alone leading to economic losses estimated at $128 million per year. The fungus covers the stomata, openings in the needles, used to exchange air and water essential for plant metabolism. As more of these stomata become clogged the tree cannot make enough glucose so the needle dies, turns yellow, and eventually the needle falls off entirely. Douglas-fir trees typically keep needles for five years, but in heavily affected areas the needles last one year before falling off leaving the tree extremely thin and frail. Even though the fungus does not directly cause death, it leaves our iconic state tree highly susceptible to drought, beetles, nutrient limitations, and wildfires.

This disease was first discovered in Switzerland, hence the name Swiss Needle Cast, in the 1920’s. At that time it was only negatively affecting Douglas-fir trees planted outside their native habitat. But since the 1980’s the natively planted Douglas-fir trees, within a narrow band parallel to the coast range, are showing annual growth decreases by as much as 50%. Recently there have been advancements in molecular biology and computing power that allow researchers to identify the genetic heritage of pathogens. Using these tools scientists can focus on population genetics to figure out why there is such a discrete area affected along the Oregon coast range. Some evidence points to  warming winters and fungal-subspecies expansion as reasons for the spread of this fungal disease. But Patrick has indications to suggest it’s death by a thousand cuts and begs the question of whether the future of forestry is in danger.

Growing up in southern California Patrick wasn’t exposed to the forests he studies today. It wasn’t until he attended Humboldt State University where he got his first exposure to towering canopies and ecology. His first research experience was in the Lassen Volcanic National Park in California where his advisor, Dr. Patricia Siering, pushed him to develop his own scientific study. Needless to say he was hooked on science and after taking a mycology class he also knew he was jazzed on studying mushrooms so he continued his passions that lead him to Oregon State University.

Dr. Patricia Siering (Humboldt State University – Biology Department) collecting boiling hot sulfuric acid from Boiling Springs Lake in Lassen Volcanic National Park in Northern California with the help of undergraduates and graduate students.

Patrick Bennett is a 4th year PhD student in Dr. Jeff Stone’s lab in the department of Botany and Plant Pathology housed in the College of Agricultural Sciences where he is investigating how population genetics can be used to better understand the factors contributing to the recent emergence of Swiss Needle Cast as a damaging forest pathogen in the native range of Douglas-fir. Be sure to tune in Sunday April 30th at 7PM on KBVR Corvallis 88.7FM or by listening live.

Searching for viruses that make plants sick

Ripening sweet cherries in Mosier, Oregon. Photo credit: Lauri Lutes

When plants get sick, they can’t be treated or cured in the same way as people who receive medicine for an illness.  Plants require specialized care by scientists who are uniquely equipped to study and treat their diseases.  As a graduate student in the lab of Dr. Jay Pscheidt in the Department of Botany and Plant Pathology, Lauri Lutes is a plant doctor looking for viruses that infect sweet cherry trees in Oregon. She is able to identify an infected sweet cherry tree by looking at symptoms, including yellow rings or discolored mottling on the leaves, or fruit that is smaller than normal. To pinpoint the identity of the virus, further tests in the lab are performed.

Mottling and ringspot symptoms on sweet cherry, Prunus avium, in Umpqua Valley, Oregon. Photo Credit: Jay W. Pscheidt

Sweet cherries are one of Oregon’s top commodities, with 12,300 acres of sweet cherry production near the Dalles and Hood River, and 3,200 acres in the Willamette valley. There are a few viruses that the Oregon Department of Agriculture looks for each year, including Plum pox virus, a quarantine pathogen in the United States. However, if sweet cherry trees are infected with something other than the most common or most damaging viruses, they may never receive a diagnosis! Lauri works with the Oregon Sweet Cherry Commission to determine where diseased sweet cherry trees are located in Oregon. During her time at OSU, Lauri has discovered a virus infecting sweet cherry trees in the Dalles region that had never been reported in Oregon!

Lauri Lutes collecting leaf samples from sweet cherry trees in The Dalles, Oregon. Photo credit: Lauri Lutes

As an undergraduate student majoring in biology at Indiana University South Bend, Lauri discovered her passion for plant biology after taking a plant systematics course. Her undergraduate research consisted of studying fungal pathogens in a native waterleaf plant that grows in the forest floor of Indiana. Lauri attributes her positive experiences in undergraduate classes and research to female professors who provided encouragement and strong mentoring. After the birth of her daughter during her senior year of college, Lauri’s path toward attending grad school diverged, and she began working at a plant pathogen diagnostics company, Agdia, Inc. There, she used magnetic particles to purify viruses from plant material and co-developed a Technical Support Department. Curiosity driven, she found that she still wanted a deeper foundation in plant pathology, which led her to pursue graduate work at OSU.

View of Mount Hood from sweet cherry orchard in Parkdale, Oregon. Photo credit: Lauri Lutes

In addition to her work with sweet cherry tree viruses, Lauri is enrolled in the Graduate Certificate in College and University Teaching (GCCUT) program, and is active in science communication, having recently been selected to attend ComSciCon-PNW (Communicating Science Conference) in Seattle. After grad school, Lauri is considering teaching at the university level and continuing her involvement in science communication. As the first person in her family to complete an advanced degree, she hopes to inspire and expose her daughter to educational opportunities she might not have had otherwise.

Please join us this Sunday, April 2nd on KBVR Corvallis 88.7FM at 7 pm PST, to hear much more about Lauri’s journey through grad school, and her research about sweet cherry tree viruses. 

You can also stream this episode live at www.kbvr.com/listen.

View from a sweet cherry orchard in the Hood River, Oregon. Photo credit: Lauri Lutes