Well, my apologies all. Life and work have been very much getting in the way, so today's entry will be one to belatedly conclude the series for UBC's Celebrate Research Week.

Lindsay introduces today's author:

Dr. Quentin Cronk is a Professor in Plant Science at UBC's Biodiversity Research Centre where he works on flower evolution in legumes and the genetic factors that underly these morphological changes. Together with his PhD student Isidro Ojeda they have investigated the distribution of epidermal types in petals of legumes and how this feature has evolved within the family.

Dr. Cronk writes:

The first picture (A) depicts the distribution of the epidermal types in a "papilionoid legume" with a typical pea-type flower, Lotus burtii. The second picture (B) depicts the same in a "caesalpinioid legume" with a caesalpinoid flower, Cassia roxburghii. The latter is thought to be a more primitive flower type. The epidermal photographs were taken using a scanning electron microscope (SEM) of fresh petals that were put directly into the microscope.

Pea-flowers, exemplified here by Lotus burttii, have three distinctive types of petals, one upper (dorsal), two side (lateral) and two lower (ventral) petals. Each petal type has a different role during the flower-pollinator interaction. For instance, due to its position within the flower, the upper petal is highly visible and acts to attract pollinators, while the side petals in papilionoid flowers are mostly used as landing platforms for bees.

Ojeda and Cronk found, in a survey of 175 species, that most pea-flower types have the distribution of epidermal types depicted in figure A. Each petal type has a specific surface structure that gives each petal its own unique identity. For instance the bumpy surface of the upper petal reflects light in a way that makes the petal brighter and more attractive to bees. In contrast, legumes with a caesalpinoid-type flower do not have this diversification of epidermal types within the flower. The different types of petals cannot be differentiated at the epidermal level. This also applies in the redbud (Cercis canadensis), which has a flower that looks like a pea-type flower, but in fact it is a caesalpinioid legume, and the petal surfaces confirm this.

This survey has allowed the identification of major epidermal types and the general trends of its evolution within the family. Furthermore, it allows us to study the link between the underlying genetic controls (petal identity genes) and petal morphology. We are applying this to understand the evolution of related legume species with very different flower types, for instance in the transition from bee to bird pollination, as described in a previous UBC Research Week.

This broad survey would not have been possible without the living plant collections of botanical gardens. For this study we used the collections of the UBC Botanical Garden, the Fairchild Tropical Botanical Garden in Florida, USA and the Jardín Botánico Regional at CICY, Mexico.

For more details of this work, please see the published paper: Ojeda et al. 2009. Evolution of petal epidermal micromorphology in Leguminosae and its use as a marker of petal identity. Annals of Botany 104(6):1099-1110. doi:10.1093/aob/mcp211.

A few more entries in the UBC Celebrate Research Week series remain. Lindsay introduces Dr. Mooney:

Dr. Patrick Mooney is a Professor in the Landscape Architecture program in UBC's School of Architecture + Landscape Architecture at UBC where he teaches sustainable landscape planning and management, ecological restoration, design studio and planting design. Dr. Mooney consults to developers, environmental groups, the B.C. Ministry of Environment, regional parks and city governments on habitat management and restoration. Dr. Mooney designed and supervised the installation of Maplewood Flats, a constructed wetland on the Burrard Inlet. The mud-flats that previously existed on that site were filled for a port facility that was never built and is now a Provincial Wildlife Management Area operated by the Wild Bird Trust (WBT) of BC. Since its installation, the WBT has recorded an increase in bird diversity from 208 bird species prior to 1995 to 231 in 2004.

Dr. Mooney writes:

Maintaining biodiversity in urban regions (PDF) requires the implementation of conservation actions that are informed by local knowledge. To meet this need, I've developed general biodiversity models that may be used to select candidate conservation areas, to enhance habitat in urban disturbed sites, to increase site level biodiversity and to guide ecological restoration for wildlife habitat.

The plant associations of three conservation areas on Burrard Inlet in the Metro Vancouver region were inventoried and mapped as habitat types (figure 1 -- the map)

The 62 species of birds that were found to use the sites on an annual basis were grouped according to their foraging guilds. The guilds are coded A through L in the second figure. It was found that that certain habitats support more species than others and some habitats support a high proportion of certain guilds.

Since most species use multiple habitats, a cluster analysis was conducted to determine which groups of habitats supported the most bird species. Three habitat assemblages - Deciduous Forest / Mixed Forest / Park; Shorezone / Old Field / Meadow and Old Field / Salt Marsh / Freshwater Marsh were found to contain the primary use habitats of the majority bird species found on the study sites (see Figure 2). All other possible habitat assemblages contained the primary habitats of three or fewer species.

Habitat Assemblage 1: Deciduous Forest / Mixed Forest / Park

Eleven species of birds from guild A, the gleaners, utilize this habitat assemblage for both primary and secondary habitat. This assemblage contains the primary and secondary habitat for 21 species. 13 of these species were found only within this habitat assemblage. These are black-throated gray warbler, brown creeper, chestnut-backed chickadee, evening grosbeak, orange-crowned warbler, Pacific-slope flycatcher, downy woodpecker, pileated woodpecker, bushtit, Cooper's hawk, cedar waxwing, Steller's jay and purple finch.

Habitat Assemblage 2: Shorezone / Old Field / Meadow

The habitat assemblage of shorezone/old field/meadow contains the primary and secondary habitat for 16 species or 25.8% of the 62 species in this analysis. This assemblage is notable in that primary and secondary use habitat for three of the four species in guild C, the probers, are captured by this assemblage. These are killdeer, solitary sandpiper, and spotted sandpiper. The exception in guild C is the sora rail which was found only in the freshwater marsh habitat type.

Habitat Assemblage 3: Old Field / Salt Marsh / Freshwater Marsh

This assemblage contained primary and secondary habitats for five species. Two species are particular to this habitat assemblage. The wood duck was found in both the freshwater and saltwater wetlands, while the sora rail occurred in only the freshwater marsh habitat.

The series for UBC's Celebrate Research Week continues today with an entry from Dr. Brian Klinkenberg today's photograph by him via Flickr) and graduate student Claire Wooten. Lindsay writes the introduction:

Dr. Brian Klinkenberg is a professor in the UBC Department of Geography where his research focuses on advanced spatial analysis with respect to physical, health and social sciences (and the intersection of these disciplines). Dr. Klinkenberg is also the editor and project coordinator of E-Flora BC / E-Fauna BC.

Dr. Klinkenberg writes: Understanding the spatial aspects of plant dynamics is a critical part of landscape ecology today. Recently in my lab our focus on spatial analysis has led us to explore the decline of yellow-cedar in BC (see gallery link at bottom of page). Exploring the spatial occurrences on these species in the landscape has led to key insights into distributions and biogeographic changes.

Claire Wooten (graduate student) and Dr. Klinkenberg co-wrote the following about yellow-cedar die-off:

For over two decades, the phenomenon of yellow-cedar decline has perplexed researchers. Yellow-cedar (Chamaecyparis nootkatensis) (D. Don) Spach), which ranges from southern Oregon to Prince William Sound, Alaska, was known to be declining on over 200,000 ha of undisturbed forest in southeast Alaska (Snyder et al. 2008). During an aerial survey in 2004, numerous large areas of dead and dying yellow-cedar were found in coastal locations in B.C., and the nature of the dieback was found to be consistent with the phenomenon in southeast Alaska (Hennon et al. 2005).

Research into the decline of this long-lived species began in the early 1980s and a sequence of symptoms was identified. The initial symptom was determined to be fine root death, followed by death of small-diameter roots (Hennon et al. 2006) (PDF). As the roots start to die, the trees develop thin off-colour crowns and necrotic lesions spread from larger roots up the bole (Hennon et al. 2006). The natural resistance of yellow cedar heartwood to decay allows dead trees to remain standing for 80 to 100 years after death. By examining the standing snags it was possible to establish that the decline of yellow-cedars began in about 1880-1900 (Hennon & Shaw, 1997).

Investigations initially focused on finding a biotic cause of the decline, but one by one the suspected agents were ruled out (Hennon et al. 1990). Attention then shifted to abiotic factors potentially associated with the decline--an association with wet, poorly drained soils was found. However the relationship with soil drainage is inconsistent, with limited decline occurring on wet sites at higher elevations (Hennon et al. 2006). Air and soil temperature were determined to be stronger risk factors than poorly drained soils (D'Amore & Hennon, 2006).

These clues led researchers to propose a new, complex hypothesis to explain yellow-cedar decline. According to Hennon et al. (2006), saturated soils create open, exposed canopies which experience soil warming early in the spring. This warming triggers the yellow-cedars to lose their cold tolerance, making them more susceptible to freezing injury. Snow appears to protect yellow-cedar against this freezing injury by preventing soil warming. However, the end of the Little Ice Age, which coincided with the onset of decline, has led to a reduction in snowpack at lower elevations (Hennon et al. 2006). This shift in climate may represent the environmental trigger responsible for the decline and suggests that the dieback may expand if warming trends continue (Hennon et al. 2006).

Our research questions are being addressed through a combination of remote sensing and GIS techniques. Spatial patterns of biophysical factors (e.g. elevation, slope, aspect) are being used in our assessment of the relations between the distribution of decline and the environmental predictors.

The high value of yellow-cedar wood and the desire to conserve species diversity means that a management strategy incorporating the influence of a warming climate is required. Ultimately, this research may provide insight into the devastating effects that climate change can have on a forest ecosystem.

Dr. Klinkenberg also adds an additional note regarding the name of this species:

There has been much debate over the taxonomic status of yellow-cedar following the discovery of a closely related tree species in northern Vietnam, Xanthocyparis vietnamensis Farjon & Hiep. Whether yellow-cedar is transferred to this newly established genus as Xanthocyparis nootkatensis or the older Callitropsis nootkatensis (D.Don) Örest name is adopted, will be determined at the next International Botanical Congress in 2011 (Mill & Farjon, 2006).

References

D'Amore, D. and Hennon, P.E. 2006. Evaluation of soil saturation, soil chemistry, and early spring soil and air temperatures as risk factors in yellow-cedar decline. Global Change Biology. 12: 524-545

Hennon, P.E., D'Amore, D., Wittwer, D., Johnson, A., Schaberg, P., Hawley, G., Beier, C., Sink, S. and Juday, G. 2006. Climate warming, reduced snow, and freezing injury could explain the demise of yellow-cedar in southeast Alaska, USA. World Resource Review. 18(2): 427-450.

Hennon, P.E., D'Amore, D., Zeglen, S. and Grainger, M. 2005. Yellow-cedar decline in the North Coast Forest District of British Columbia. Res. Note RN-549. Portland, OR: U.S. Dep. Agric., Pacific Northwest Research Station. pp.20.

Hennon, P.E. and Shaw, C.G. III. 1997. The enigma of yellow-cedar decline - What is killing these long-lived, defensive trees? Journal of Forestry. 95(12): 4-10.

Mill, R. R. And Farjon, A. 2006. Proposal to conserve the name Xanthocyparis against Callitropsis Oerst. (Cupressaceeae). Taxon. 55(1): 229-231.

Snyder, C., Schultz, M.E. and Lundquist, J. (Compilers) 2008. Forest health conditions in Alaska - 2007: a forest health protection report. Gen. Tech. Rep. R10-PR-18. Anchorage, AL: U.S. Dep. Agric., Forest Service, Alaska Region.

Thank you to BlueRidgeKitties@Flickr for contributing photographs to complement today's entry for the UBC Celebrate Research Week series (original image 1 | original image 2 | UBCBG Botany Photo of the Day Flickr Pool). Much appreciated!

Lindsay Bourque introduces Dr. Li:

Dr. Xin Li is an Associate Professor in the UBC Department of Botany and a research fellow in the Michael Smith Laboratories. Her lab's research focuses on understanding the innate ability of plants to defend themselves against pathogen infection. Using the model organism Arabidopsis thaliana to understand new regulatory components of plant disease resistance, Dr. Li sees a potential application in environmentally-friendly agricultural disease control. Arabidopsis thaliana is an annual native to most of Europe, Asia and northwestern Africa. It was the first plant genome to be entirely sequenced and was designated as a model organism in 1998. There are several features that make Arabidopsis thaliana (commonly known as thale cress or mouse-ear cress) an ideal model organism, including: a rapid life cycle (about 6 weeks from germination to mature seed), small genome and the availability of mutant lines (hence variation in disease resistance) and genomic resources through Stock Centres.

Dr. Li writes:

Plants have evolved sophisticated disease resistance mechanisms through long history of dealing with microbial pathogen infections. The kind of immunity we study is mediated by resistance proteins (R proteins), which are conceptually similar to animal innate immunity receptors. There are two basic functions of plant R proteins as immune receptors. One is to recognize the presence of the pathogen, and the second is to initiate a robust defense response to fight against the pathogen invasion. The conserved nature of R protein mediated resistance makes it possible to be studied in model plant-pathogen systems where the organisms have short life cycles, are easy to manipulate and have the great benefit of advanced genetic and genomic resources. For higher plants, that choice is Arabidopsis thaliana, the mouse-ear cress model that helps us solve mysteries in plant biology like the fruit fly (Drosophila melanogaster) helps solve questions in animal development. Better understanding of plant R protein mediated immunity will not only help us develop better environmentally friendly disease control strategies in crop fields, but it can also lead to a better understanding of some of the animal immunity mechanisms mediated by receptors similar to R proteins.

In Arabidopsis, there are more than 200 predicted R genes. We previously identified a unique gain-of-function mutant snc1 by chance and it encodes an R gene. Our lab has developed snc1 as an autoimmune model to dissect the molecular events occurring after resistance proteins are activated. In the snc1 mutant, a point mutation resulting in a single amino acid change (glutamic acid to lysine) renders the SNC1 R protein constitutive active without interaction with pathogens. As a consequence of constitutive defense that reallocates resources from normal growth and development, the stature of the mutant plants is dwarf and the morphology sickly. Intriguingly, similar mutations in the same region of mammalian immune receptor Nod2 are also associated with human autoimmune Crohn's disease. The size of the mutant plants correlates with the level of defense, providing an easy readout of the immune responses (Figure 1).

Daniel adds: In other words, Dr. Li's lab is tackling the questions: what happens when a resistance protein is activated? What happens when a resistance protein is "always on" or at elevated levels? Even though there are benefits (a correlation between high resistance protein levels and minimal pathogen infection), there are also disadvantages (a negative correlation between high resistance protein levels and typical plant growth). This leads to the next series of questions asked by Dr. Li's lab: is it possible to grow plants with both high resistance protein levels and still have typical plant growth? If so, how? If successful and the relevant techniques are applied to crops, then it may be possible to have more environmentally-friendly food production, perhaps by reducing pesticide use or increasing yield/ha (and thus not requiring as much land for food production).

Returning to the series for UBC Celebrate Research Week, Lindsay introduces Dr. Rick Barichello:

Dr. Richard Barichello is a Professor in UBC's Faculty of Land and Food Systems and focuses on issues of agricultural economic policy, including policy reform in southeast Asian countries.

Dr. Barichello writes (excerpted from the article, "Agriculture in Indonesia: Lagging Performance and Difficult Choices"):

Poverty remains a major social issue in Indonesia, by any measure. Because most poverty is still located in rural areas, many agricultural policies embrace the rhetoric of poverty alleviation as one of their objectives. In the first two decades of the Suharto period, to the mid-1980s, agricultural policies that supported rice production contributed to pro-poor economic growth and reduced rural poverty. Poverty declined from 1990 to the Asian financial crisis of 1997/98, rose sharply with the crisis but declined again steadily from 1999 to 2008.

But over the past two decades, the contribution of these policies to economic growth has been reduced; government priorities shifted away from productivity-enhancing policies and flowed to rice price protection policies whose costs were growing. In addition, the leverage of agricultural price policies on rural poverty has been reduced. Raising the price of rice no longer reduces poverty because the poorest Indonesians are net rice consumers, wage rates now appear to be influenced most heavily by the non-farm labor market, and the benefits of price policies have been strongly tilted toward farmland owners. There have been efforts to soften the impact of higher rice and cooking oil prices for the poorest consumers through targeted consumer subsidies ("rice for the poor" targeted 19 million poor households in 2008), and expenditures on these programs increased in response to the 2008 price increases. The current price is roughly 10% above the world price for medium quality rice, but a 50% margin has been a good guide overall from 2000 to 2007. There is a longstanding political demand for protection of rice in Indonesia. That protection takes the form of preventing decreases in its price through the use of trade policy instruments, namely a tariff plus exclusive import rights granted to a well-known state enterprise, BULOG (the State Logistics Board).

Overall, rural poverty has been reduced since 1999 (figure from article), but this has been due to strong nonfarm economic growth and a dynamic rural labor market that features substantial off-farm employment and rural-urban migration. Among rice farmers, the supposed beneficiaries of higher rice prices, land owners are likely to capture most of the gains, while wage earners in rice farming (the landless) capture little if any. So, although the alleviation of poverty is still promoted as an important issue for agricultural policy, this is now largely political rhetoric. Much more could be done.

Daniel adds: Today's photographs are part of the image collection of the International Rice Research Institute (original image 1 | original image 2).

Continuing with the series for UBC Celebrate Research Week, Lindsay introduces Dr. Gary Bradfield:

Dr. Gary Bradfield is an Associate Professor with the UBC Department of Botany where he researches and lectures on plant community ecology.

Dr. Gary Bradfield writes:

Plant communities of forests, grasslands, and wetlands form a living tapestry that clothes the broad spectrum of terrestrial landscapes in which we live. The diversity of these communities, both in species composition and vegetation structure, provides enormous ecological benefits to a myriad of other, non-plant, species, and immeasurable social and economic values to human society. One of our great challenges for the 21^st century will be to deepen our respect and understanding of plant diversity to ensure its rightful protection into the future.

There are currently four ongoing research collaborations in my lab:

Climate change impacts on BC grasslands (image 1). As part of a large interdisciplinary team, we (graduate student Robbie Lee co-supervised by Drs. Gary Bradfield and Maja Krzic) will be examining the extent of invasive plant species in grassland communities and developing predictions of directions and rates of expansion of invasive species as future warming occurs.

Vegetation ecology of riparian buffers (image 2) after logging in high elevation forests. Spearheaded by Dr. Lyn Baldwin and graduate students Christine Petersen and Scott Black, we are examining relationships between the width of uncut strips of forest along streams ("buffer strips") and the diversity and re-colonization potential of the plant species they contain.

Vegetation responses to peatland re-wetting in Québec (image 3 of Andromeda polifolia taken by Steve Henstra in Yukon, but the species also grows in Québec). Linking to the Peatland Ecology Research Group at Université Laval, we (graduate student Steven Henstra co-supervised by Drs. Gary Bradfield and Line Rochefort) will be investigating the trajectory and timing of community-scale vegetation change resulting from hydrological restoration in several historically mined peatlands.

Post-fire succession in Interior Douglas-fir (Pseudotsuga menziesii var. glauca) forests of southern BC. With recent graduate students Kaeli Stark and Scott Black, and in collaboration with Dr. André Arsenault, we are examining how plant communities re-assemble in the early stages after the devastating forest fires of 2003. The results are offering guidance for post-fire management actions such as seeding and salvage logging. Species such as Chamerion angustifolium subsp. angustifolium, shown in the image above (image 4), is a pioneering species that colonizes after forest fires, hence its common name fireweed.

Today's BPotD is the second in the series of BPotD's contribution to the 2010 UBC Celebrate Research Week.

Lindsay organized today's entry, selected the links, and introduces Dr. Suzanne Simard:

Dr. Suzanne Simard is a professor with the UBC Faculty of Forestry, where she lectures on and researches the role of mycorrhizae and mycorrhizal networks in tree species migrations with climate change disturbance. Networks of mycorrhizal fungal mycelium have recently been discovered by Professor Suzanne Simard and her graduate students to connect the roots of trees and facilitate the sharing of resources in Douglas-fir forests of interior British Columbia, thereby bolstering their resilience against disturbance or stress and facilitating the establishment of new regeneration.

Dr. Simard writes:

Mycorrhizal fungi form obligate symbioses with trees, where the tree supplies the fungus with carbohydrate energy in return for water and nutrients the fungal mycelia gather from the soil; mycorrhizal networks form when mycelia connect the roots of two or more plants of the same or different species. Graduate student Kevin Beiler has uncovered the extent and architecture of this network through the use of new molecular tools that can distinguish the DNA of one fungal individual from another, or of one tree's roots from another. He has found that all trees in dry interior Douglas-fir (Pseudotsuga menziesii var. glauca) forests are interconnected, with the largest, oldest trees serving as hubs, much like the hub of a spoked wheel, where younger trees establish within the mycorrhizal network of the old trees. Through careful experimentation, recent graduate Francois Teste determined that survival of these establishing trees was greatly enhanced when they were linked into the network of the old trees.Through the use of stable isotope tracers, he and Amanda Schoonmaker, a recent undergraduate student in Forestry, found that increased survival was associated with belowground transfer of carbon, nitrogen and water from the old trees. This research provides strong evidence that maintaining forest resilience is dependent on conserving mycorrhizal links, and that removal of hub trees could unravel the network and compromise regenerative capacity of the forests.

In wetter, mixed-species interior Douglas-fir forests, graduate student Brendan Twieg also used molecular tools to discover that Douglas-fir and paper birch (Betula papyrifera) trees can be linked together by species-rich mycorrhizal networks. We found that the mycorrhizal network serves as a belowground pathway for transfer of carbon from the nutrient-rich deciduous trees to nearby regenerating Douglas-fir seedlings. Moreover, we found that carbon transfer was enhanced when Douglas-fir seedlings were shaded in mid-summer, providing a subsidy that may be important in Douglas-fir survival and growth, thus helping maintain a mixed forest community during early succession. This is not a one-way subsidy, however; graduate Leanne Philip discovered that Douglas-fir supported their birch neighbours in the spring and fall by sending back some of this carbon when the birch was leafless. This back-and-forth flux of resources according to need may be one process that maintains forest diversity and stability.

Mycorrhizal networks may be critical in helping forest ecosystems deal with climate change. Maintaining the biological webs that stabilize forests may help conserve genetic resources for future tree migrations, ensure that forest carbon stocks remain intact on the landscape, and conserve species diversity. UBC graduate student Marcus Bingham is finding that maintaining mycorrhizal webs may be more important for the regeneration and stability of the dry than wet interior Douglas-fir forests, where resources are more limited and climate change is expected to have greater impacts. Helping the landscape adapt to climate change will require more than keeping existing forests intact, however. Many scientists are concerned that species will need to migrate at a profoundly more rapid rate than they have in the past, and that humans can facilitate this migration by planting tree species adapted to warm climates in new areas. UBC graduate student Brendan Twieg is starting new research to help us understand whether the presence of appropriate mycorrhizal symbionts in foreign soils may limit the success of tree migrations, and if so, to help us design practices that increase our success at facilitating changes in these forests.

Daniel adds: Some housecleaning bits to add. Dr. Simard noted that a version of today's BPotD appeared in the Faculty of Forestry's newsletter Branch Lines, here: Simard, S.W. (2010) Why research matters to the forest systems of BC (PDF). Branch Lines, 20: 4-5. Dr. Simard also contributed the photograph of Cantharellus formosus. The illustration of the fungi and tree is courtesy of Shannon Wright. The schematic of the fungal network is by Kevin Beiler, and was published in: Beiler KJ, Durall DM, Simard SW, Maxwell SA, Kretzer AM. 2010. Architecture of the wood-wide web: Rhizopogon spp genets link multiple Douglas-fir cohorts. New Phytologist, 185: 543-553.

Today starts the annual series featuring research at the University of British Columbia as part of Celebrate Research Week. Note: the photograph of the plant was not submitted as part of the entry, but I added it for illustrative purposes: Macaranga peltata by J.M. Garg of Wikimedia Commons.

Lindsay introduces Dr. Reinhard Jetter:

Dr. Reinhard Jetter is an Associate Professor with joint appointment in both the Botany and Chemistry Departments at UBC. He also holds the Canadian Research Chair in Natural Plant Products. His research projects focus on plant biochemistry, especially on the mechanisms with which plants defend themselves against herbivores and adverse climatic conditions.

Dr. Jetter writes:

We use gas chromatography and mass spectrometry to analyze the chemical composition of plant surfaces. The chemical profiles differ greatly between species and between different organs of the same plant, in some cases even within one organ - for example between the upper and the lower sides of the same leaf. This can be seen in one of our projects where we found that the leaves of diverse Macaranga species are covered with compounds forming a smooth coating (first image via scanning electron microscope), whereas the stems of the same plants exhibit a surface that is very rough due the presence of microscopic crystals (inset image).

The crystals make those stem surfaces slippery for walking insects, and so help to protect the plant against many small herbivores. Slippery surfaces are difficult to scale only when they are inclined or even vertical, but would be useless on horizontal organs. So it makes a lot of sense that the plants make crystals only for the stems and not for the leaves. How do plants manage to be so efficient in the use of this defence mechanism? We found out that the slippery crystals consist of special compounds called triterpenoids, which are very similar to cholesterol. They are being made solely for this purpose, and we are currently investigating the genes and enzymes involved in their synthesis.

In other projects, the Jetter lab is studying the biochemistry of skins of crops (rye, tomato) and model species such as Kalanchoe daigremontiana ( commonly known as "mother of thousands") and Arabidopsis thaliana (thale cress). We want to understand how each species makes and accumulates different chemical compounds at the surface of its organs, and what their individual biological functions are.

Daniel adds: As an aside to local readers, I'll be giving a lecture on Monday: Biodiversity of Southern Alaska and Yukon. This is part of our education theme for this month on "Biodiversity and the North". The BPotD series on the topic will take place later in March.

Today concludes the UBC research series. We still have a few outstanding entries, but we'll add them to the general mix. Ruth continues with the series:

Dr. Lacey Samuels is an Assistant Professor in the UBC Department of Botany. Her research initiatives mainly focus on plant cell biology and the secretion of the cell wall.

Heather McFarlane is a PhD candidate from Dr. Samuels' lab and she writes: "The picture above is a cryo-scanning electron micrograph of mint (Mentha ×piperita) leaf surface (scale bar = 100 micrometers). Mint secretes essential oils into glands (G) on the surface of its leaves. These glandular trichomes are distinct from other types of trichomes, such as hairs (H). In nature, mint essential oils may serve to protect the plant against insect and other herbivores. Commercially, these oils are employed in a variety of products. In the Samuels lab, we study lipid export, using mint essential oil export to glandular trichomes as one model system."

"We also study lipid export using Arabidopsis thaliana and Sorghum bicolor as model systems. Cryo-SEM allows us to freeze cells that are actively exporting essential oils, and to examine these cells at high magnification. This helps us gain insight into the possible mechanisms of lipid export to and from plant cells."

After yesterday's interlude, we return to the UBC research series. Ruth continues:

Assistant Professor Jin-Gui Chen from the UBC Botany Department conducts research in plant cell biology. He writes: "Trichomes are hair-like epidermal outgrowths on the surface of leaves, stems and some floral organs. It is generally recognized that trichomes have protective roles. For example, trichomes interfere with the feeding of some herbivores. The most important trichome for human beings is the cotton fibre. Many trichomes, such as glandular trichomes in lavender (Lavandula) and peppermint (Mentha × piperita) are also important places for oil and fragrance production."

"By studying model laboratory plant Arabidopsis thaliana, scientists have found that the number and distribution of trichomes are largely determined by the interactions and competitions between several different types of transcription factor--proteins that regulate the expression of target genes. These studies make it possible to alter the number, property (e.g. length), and distribution of trichomes in plants with economic values. Shown on the top are leaf trichomes in a normal (wild-type) Arabidopsis plant. By controlling the expression level of certain transcription factors, the leaf could become glabrous (the middle photograph) or very hairy (the bottom image)."

Ruth continues with the series on UBC research:

Dr. Sally Aitken is a member of the UBC Faculty of Forestry. She heads many research initiatives through the Centre for Forest Conservation Genetics.

Sally writes: "Whitebark pine (Pinus albicaulis) is a keystone species of many high-elevation environments in British Columbia and the western United States. The wingless seeds of this pine are dispersed by the Clark's nutcracker (Nucifraga columbiana), and these seeds are also a key pre-hibernation food for grizzly bears in some regions. Populations of this five-needled pine are being decimated by a combination of the introduced fungus, Cronartium ribicola, which causes the disease whitebark pine blister rust, as well as the current epidemic of the mountain pine beetle (Dendroctonus ponderosae). Rapid climate change presents yet another threat to this species."

"At the Centre for Forest Conservation Genetics in Forest Sciences at UBC, we are evaluating levels of genetic diversity and developing models to predict the distribution of habitat for this species under various climate change scenarios. PhD candidate Sierra Curtis-McLane is testing these predictions by planting seeds in subalpine habitats within the current species range and in model-predicted areas north of the range. She is also growing seedlings in controlled growth chamber experiments under different temperature and drought regimes. We hope the results will assist in restoration efforts for this ecologically important species."

We've had an exceptional response from UBC researchers contributing material for UBC Research Week, so even though this is the last official day, we're going to continue highlighting UBC Research next week.

Ruth worked with Dr. Andrew Riseman from the UBC Faculty of Land and Food Systems and David Bradbeer & John Hart of The Centre for Sustainable Food Systems at UBC Farm for today's entry on sweet potato cultivar trials for Pacific Northwest production. Today's photographs are by David Bradbeer and are part of a set available on Flickr: Sweet Potato and UBC@Flickr.

Andrew and David write:

"The Centre for Sustainable Food Systems at UBC Farm (CSFS), within the Faculty of Land and Food Systems, promotes food system sustainability through research, teaching, and outreach activities. As part of their research activities, new crop evaluations are ongoing. The climate of the Pacific Northwest represents a challenge for growing many tropical and sub-tropical crops due to relatively low temperatures. However, many valuable crops fall within this category and if suitable genotypes were identified, could add important diversity to a production system. One crop currently under evaluation is sweet potato, a tropical plant in the genus Ipomoea (morning glory). However, short growing seasons can limit yield, especially in cultivars that require >120 days to reach maximum yield. Ideally, sweet potato cultivars that reach maturity early would be appropriate choices for small-scale farmers in the Pacific Northwest that wish to diversify the selection of vegetables they can offer to their clientele."

"Nine sweet potato cultivars were collected, propagated and grown at the CSFS in 2006 and 2007 as part of a pilot feasibility study. The cultivars evaluated included 'Excel', 'B18', 'T68', 'Georgia Jet', 'Georgia Jet Bicolour', 'Korean Purple', 'Owairaka Red', 'Toka Toka Gold', and 'Nancy Hall'. Results indicated that sweet potatoes can be grown in this climate but that significant challenges remain including heat unit accumulation (i.e., time to maturity) and soil-pest management. Therefore, the 2008 trials focused on evaluating earliness and wire-worm resistance of the eight best cultivars from the previous seasons."

Ruth adds: Wireworm is a stage in the lifecycle of a group of beetles called the click beatles, from the family Elateridae.

Andrew and David continue: "In 2008, the trial compared yields from plants harvested at 90 and 120 days after planting. Initial results indicate significant differences among cultivars and that some were sufficiently suited to short season growing (i.e., those that produced a marketable amount of biomass before 90 days), and therefore appropriate for small-scale production in the Pacific Northwest. In addition, several remaining challenges were identified and include: the propagation of planting stock, the cost-effective use of clear plastic mulch to provide essential early-season soil heating, management of wire worm infested soils to avoid excessive root damage, and the establishment of climate-controlled systems for curing the roots after harvest."

"This sweet potato project represents real-world agroecology in action. Small-scale crop evaluations such as this present an ideal opportunity to train the professionals needed to assess, restructure, and develop the cropping systems of the future. However, much work remains for both assessing the role of sweet potatoes in the Pacific Northwest crop rotations but also in designing truly sustainable production systems and training those who will manage them."

Today's entry for the UBC Research Week series is courtesy of Kevin Kubeck (Greenhouse Manager / Horticulturist in the UBC Department of Botany) and Hannes Dempewolf, a graduate student in botany, who you may remember from the series last year on underutilized species. The photographer is Daniela Horna, who works for the International Food Policy Research Institute in Washington, D.C.

Kevin writes (with input from Hannes):

Here is a project to tantalize the taste buds as well as a great example of collaboration.

Theobroma cacao L. (Malvaceae) has already been featured on BPotD, so I'll give some additional information in the context of this specific project.

World Cocoa Foundation, an umbrella group for sustainable cacao farming, remarks that there are between 5-6 million cacao farmers worldwide with a production of 3 million tons per year. Similar to coffee production, most of the cacao farming takes place in tropical regions of the world where issues of fair trade, economic and agricultural sustainability as well as biodiversity are tantamount. The hope is to increase the value of the cacao product, by identifying the best varieties for each region. Like a fine wine, single-source chocolate commands a better price on the market because of its gourmet qualities.

In a partnership between Bioversity International, the Ministry of Agriculture of Trinidad and Tobago, the Cronk and Rieseberg Labs, the USDA and the World Bank, PhD candidate Hannes Dempewolf hopes to use molecular techniques to address issues of interest to cacao farmers.

The primary goal is to try and find genetic markers that identify specific varieties of cacao, a chocolate fingerprint if you will. Many traditional markers rely on chromosomal DNA but these can confound lineages because chromosomes are inherited from both parents. Plastid DNA, the small circular DNA inside chloroplasts can be a more reliable test for lineage because the plastids are inherited maternally. The caveat is that the plastid is harder to isolate -- a requirement for the subsequent sequencing step. Recent advances in 'high throughput' sequencing have opened up the possibility of rapidly sequencing multiple entire plastid genomes in order to compare them and identify variable regions for the establishment of a standardized fingerprinting method. This DNA fingerprinting technique can then be used to identify specific varities, allowing chocolate traders, exporters and manufacturers to reliably identify and trace varieties along the value chain. Chocophiles rejoice!

Theobroma used to be placed in the Sterculiaceae, but has been moved recently into the Malvaceae along with several other well known genera in families such as Bombaceae and Tiliaceae. The Malvaceae Info site details and displays the species now placed in the Malvaceae by the Angiosperm Phylogeny Group.

Ruth continues with the series for UBC Research Week:

Carolina Chanis is a UBC Biology student. She works in Dr. Jack Saddler's research lab and you may recognize her name from previous BPotD contributions of bryophyte microscopy. She calls this composition "pulp art". This geometric design contains the results of different treatments on corn stover. Corn stover is the debris left over from corn harvest. Corn leaves, stalks, husks and cobs are collected and ground for processing. The different pulp samples were treated with acid, ethanol and temperature in varying combinations and amounts. The different responses to treatment resulted in the color, texture and degree of degradation made visible in this photograph. Carolina took these photos during her co-op study program.

Carolina writes: "The Forest Products Biotechnology group, led by Dr. Jack Saddler, investigates the production of second-generation biofuels from lignocellulosic materials. We are particularly interested in the use of beetle-killed Pinus contorta (lodgepole pine) as a source for biofuels. The Dendroctonus ponderosae (mountain pine beetle) epidemic in British Columbia has killed more than half of the lodgepole pines in the province, reducing the value and quality of the wood. By using this otherwise discarded wood, we can produce clean energy and reduce the risk of wild fires caused by the dead trees that are not harvested. The group is also working on Picea (spruce), Pseudotsuga menziesii (Douglas fir), Tsuga (hemlock) and agricultural residues such as corn stover."

"Our team uses two different methods for bioconversion: steam explosion, which uses steam at high temperature and pressure, and the ethanol Organosolv process, which uses ethanol and an acid catalyst such as sulfuric acid too 'cook' the pulp at high temperature and pressure. The Organosolv process is essentially used to extract sugars for processing. We also study the subsequent stages in the bioconversion process: enzymatic hydrolysis and fermentation. Our scientific research is coupled to studies in economic performance in order to develop the most cost-effective strategy for a sustainable future."

Ruth continues the UBC Research Week series:

Here is Dr. Mark Vellend describing his research on the "ecology, genetics, and conservation of plant populations and communities on southeastern Vancouver Island and the southern Gulf Islands." Dr. Vellend has contributed this piece along with these photographs of Camassia quamash and a landscape shot of Mount Tolmie on Vancouver Island.

Mark writes: "The forests and grasslands in and around southeastern Vancouver Island harbor dozens of federally-listed rare species, and are of immense aesthetic, cultural, recreational, and economic value to people. The structure, composition, and diversity of these ecosystems in the present day is influenced not only by natural environmental gradients and obvious human disturbances such as suburban and agricultural development, but also by less obvious changes in land use and management practices of native peoples over the past 200 years."

"Our research employs a variety of methods and data sources -- ranging from land survey records from the 1850s, present-day surveys of plant communities, molecular-genetic analyses of particular species, and geographic information systems -- to characterize the influence of past and present, and natural and anthropogenic processes on biodiversity in this region. For example, we have found dense human populations around regional parks impact native plant species detrimentally, while encouraging non-native species. Historical land survey records and geographic analyses have revealed a clear signal of prescribed fire by native peoples maintaining open savannas to a far greater extent, and in a wider variety of environmental conditions, than today. The main traditional food plant of native peoples - camas - shows strong genetic differentiation across space, but no obvious influence of historical bulb trading. Ongoing research addresses the response of butterflies (PDF) to environmental and plant-community changes in this region, and will integrate different sources of historical data to provide a comprehensive picture of how and why plant communities have changes over the past two centuries.