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.

Ruth continues with the UBC Research Week series:

Patrick Martone is a UBC Assistant Professor. His laboratory studies the biomechanics, evolution and functional morphology of marine algae.

Patrick writes: "One central research theme in my lab is to understand how intertidal seaweeds resist the relentless barrage of waves breaking on shore. Past studies have shown that, by being flexible, seaweeds reconfigure and reorient in flow to reduce drag. This paradigm holds even for many erect calcified algae, which locally decalcify to form flexible joints between calcified segments. Recent studies in my lab have investigated the biomechanical properties and chemical composition of the joints in the articulated coralline Calliarthron, which often dominates wave-exposed coastlines in California. We discovered that the joints in this red alga contain lignin, a primary component of wood in terrestrial plants, and are stronger, stiffer, and tougher than other algal tissues."

Daniel adds: Monterey Bay Aquarium has more details about this genus of algae and a few others.

Ruth has assembled the following series, running all of this week. Ruth writes:

It's Celebrate Research Week here at UBC! Free seminars & lectures, open houses, and symposia are held throughout the Lower Mainland and the Okanagan to inspire and inform the public. On Botany Photo of the Day, we're joining in with a series on UBC research (and researchers!) as a way to show our appreciation for all the hard-working research folk from the underground laboratory world -- the ones only seen late at night traveling the transit system to get a few hours of sleep at home before heading back to the lab in the early morning. Thank you!

Arabidopsis thaliana is a well-researched species within the Brassicaceae. Its genome is especially tiny, at only 125 Mb (million base pairs) -- all of which are sequenced. Many of the researchers in the UBC Department of Botany are working with this species and examining it from many different approaches.

George Haughn of the UBC Botany department writes a few words about his research:

"The seed coat is a specialized tissue that develops following fertilization to provide a protective layer for the embryo. In some species, including Arabidopsis thaliana, the seed coat epidermal cells synthesize and secrete large quantities of polysaccharide mucilage between the cell membrane and primary cell wall."

Ruth interjects: Mucilage is a polymer of sorts found in plants. It is thought to aid in water storage and seed germination. Cacti and succulents tend to have a great deal of mucilage. If you have ever treated a sunburn with a home remedy you can just imagine that goo from inside an aloe.

George Haughn continues: "Upon exposure of the mature seed to water, the mucilage swells, ruptures the primary cell wall and envelops the seed to form a protective layer. This mucilage is similar in composition to a major component of the plant and secondary cell wall (pectin) that is important for cementing of plant cells together. Because mucilage is made in large quantities at a specific time in development, it can easily be isolated. It is not required for viability under laboratory conditions."

"The Arabidopsis seed coat epidermal cells represent a useful model system for using genetics to study complex polysaccharide biosynthesis and secretion. We use mutants unable to produce normal mucilage as an approach to identifying and cloning genes that are required for these processes with the intent to better understand cell wall structure and function."

The series for UBC Research Week is coming to a close soon. Connor's helped assemble this entry:

Andrew Riseman, an Associate Professor in the Faculty of Land and Food Systems at UBC and Ornamental Plant Breeder at the UBC Botanical Garden, shares his research on the various means by which plants can prevent self-pollination.

These photographs were taken from a research project evaluating self incompatibility in the genus Staphylea. Self-incompatibility systems act in promoting outcrossing (i.e., increasing genetic diversity) by only allowing non-self pollen to complete fertilization. These systems can be morphological (e.g., imperfect flowers where male or female organs are absent), developmental (e.g., protandry when the anthers reach anthesis before the stigmatic surface is receptive), or genetic (e.g., gametophytic self- incompatibility (GSI) where pollen tube growth of only self-pollen is disrupted by pistil tissue). In Staphylea, a GSI system appears to be present. These images are from outcross pollinations (i.e., compatible) between two Staphylea holocarpa var. rosea accessions maintained at the UBC Botanical Garden. As expected from a compatible cross, pollen grains successfully germinate and penetrate the stigmatic surface (photo 1). Pollen tubes continue to grow through the style to the ovary with individual tubes reaching separate ovuals (photo 2). Once fertilization is complete, fruit containing the newly formed seeds are produced (photo 3). The fourth photo shows a Staphylea flower post-anther dehiscence.

Connor Fitzpatrick continues with the series for UBC Research Week:

Scott Black is a Botany grad student at UBC. He is researching the ecological effects of post-wildfire management practices on the interior douglas fir forests, Pseudotsuga menziesii, of Southern British Columbia.

Disturbances such as forest-fires were once thought to be purely destructive forces, however, now they are seen in a more positive light. Disturbance (PDF) is now considered an important factor in maintaining the biodiversity of many natural ecosystems. Study of the effects of disturbance on plant community structure and, resource levels has initiated many ecological theories including the competitive exclusion and intermediate disturbance hypotheses. Disturbances are essential to ecosystem composition, function and sustainability but how much disturbance is too much?

Post-wildfire management in BC includes salvage logging, grass seeding and stump flipping. These practices increase the disturbance frequency and can potentially alter a plant community’s response after wildfire (here is a study, PDF, evaluating the effects of grass seeding). With 187 plant species and 98 animal species living in the interior douglas fir forests that are either red or blue listed (via the BC Ministry of Environment), an understanding of the effect of post-wildfire management practices on ecosystem health is crucial.

Salvage logging (PDF) can reduce the species diversity of plant communities, and reduce the number of tree seedlings after a fire. Soil loss / compaction and an increase in invasive species are results of salvage logging. Furthermore, the removal of burnt logs reduces the number of habitats for certain wildlife, especially birds, and can create unfavourable conditions for native understory vegetation.

In 2003, BC had a total of 2473 fires consuming 265,053 ha of forest (from the BC Ministry of Forests and Range), and fire frequency is expected to increase with climate change. Scott is comparing the plant communities found in post-wildfire sites that have been salvage logged, grass seeded, and left untouched. By uncovering the relationship between plant community structure, environmental characteristics and post-fire forest management practices Scott hopes to increase the sustainability of BC’s interior forests.

The first picture shows the ubiquitous post-fire species, Chamerion angustifolium, amidst a stand of burnt interior douglas firs. Fireweed has very deep rhizomes that sprout after fire and wind dispersed seeds that quickly cover burnt areas. It is also used as an ingredient in the cosmetic industry. This picture was taken in the McGillivray Fire north of Chase, BC last summer. The second picture shows the salvage logging process. The picture is courtesy of the Ministry of Forests and Range and was taken near MClure BC, North of Kamloops

(Adapted from Scott's 2007 proposal)

Here (PDF) is a report on wildfire management practices in western America.

The series for UBC Research Week continues. Today's write-up and photos are courtesy of Toko Mori. Toko writes:

My name is Toko Mori, a first-year graduate student in the Berbee Lab at the University of British Columbia. I study chytrid fungi, microscopic fungi that mainly live in freshwater. I especially focus on the local chytrids that parasitize freshwater microscopic algae. My long-term research goal is to create a tree of life of chytrids that parasitize algae and to see if there is any coevolutionary relationship between the species of parasitic chytrids and those of their host algae. I collected this chytrid on an alga, Vaucheria, from Burnaby Lake (Burnaby, BC) in August 2007. I have cultured it on agar and also co-cultured it with Vaucheria since then.

Since it seems that this is the first entry of chytrids in the Botany Photo of the Day, let me explain what they are. Chytrids are fungi, although they look quite different from mushrooms and molds, which we often think of as fungi. There are about one thousand species of chytrids which form the Phylum Chytridiomycota. Being the only group of fungi which reproduce by motile cells called zoospores (shown in picture 4), chytrids are considered to have diverged from the other fungi very early in their evolutionary history. Having motile spores gives them reproductive advantage in water. However, this is a double-edged sword; chytrids are unable to reproduce without moisture and thus bound to aquatic habitats.

Chytrids have recently attracted public attention as a cause for the population decline of amphibians. However, not all the chytrids are amphibian pathogens. To the contrary, many chytrid species are decomposers of organic matter in ponds and lakes, or parasites of microscopic invertebrates or algae, as in this case. Not much is known about their ecological roles.

Now let me explain these pictures. You are witnessing the moment of zoospore release, the highlight of their life history. The small round structure on the algal filament in picture 1 is a mature sporangium, where zoospores are produced. (The big bulge at the right end is a part of the alga, which I will explain later.) You can see the sporangium filled with small dots, each representing a zoospore. Five minutes later, the zoospores start to leave the sporangium, probably triggered by the sudden change in temperature caused by the intense light from the microscope. The change in pH of the surrounding water (when transferred from culture to a drop of distilled water on a slide) may also be the trigger. For a few minutes after the release, zoospores swarm just outside of the sporangium, until they start to swim away as in picture 3. As you may see in picture 4, the zoospores (ca. 4µm in diameter) have a flagellum like that of animal sperm. Eventually these zoospores stop swimming, retract their flagellum and encyst on a suitable substratum if they find one. Then they themselves will grow into a new sporangium, produce zoospores inside by mitosis, and start a new cycle of asexual reproduction.

A note for this alga. To co-culture this chytrid with its host, I received the culture of the host algal species, Vaucheria sessilis, from the Canadian Center for the Culture of Microorganisms at UBC. Vaucheria is unusual in that it lacks cell walls except when making reproductive structures; this entire filament seen here is one cell. The bulging end was formerly a spore, from which this algal filament grew.

Species identification is an important part of my research. Correct identification is the first step to making a tree of life. However, species identification of chytrids can be often difficult due to their simple body structure - there are not many morphological characters to study, at least on the light microscopy level. These days researchers combine molecular data and electron microscopy, together with traditional morphology. I have identified this chytrid down to the genus Chytriomyces, based on the light microscopic level morphology and molecular data.

Connor Fitzpatrick continues with the series for UBC Research Week: Dr. Shannon Cowan is an Assistant Professor in the Faculty of Land and Food Systems. She shares her research today.

Dr. Shannon Cowan is conducting community-based plant research with B.C. First Nations in Nlaka'pamux Siska Band and Boston Bar Band.

Traditional food is associated with "healthy eating and living" in Aboriginal Canadian communities (here is an article, second from top, exemplifying this point). Current dietary practices in Aboriginal communities are also inextricably tied to cultural traditions and norms, which have seen significant shifts in Canada in the last few decades. Traditional food resources themselves are changing based on political and physical modification of environments including climate change, industrial development and contamination. There is a lack of research evidence regarding traditional food plant knowledge / beliefs and practices and how that affects traditional food consumption and health in Aboriginal communities.

Interdisciplinary research linking ecological knowledge, dietary knowledge and practices is needed to improve nutritional status in Aboriginal Canadians, and must be informed by an understanding of contemporary patterns of food procurement, preparation and distribution.

The Siska-UBC research team includes a Siska Community Research Committee (H. Michell, C. Michell, B. Munro, M. Williams), Siska Traditions Society Board Members, Siska Chief F. Sampson, UBC graduate student N. MacPherson, community member researchers and participants, and Dr. S.E. Cowan (UBC Faculty of Land and Food Systems, Botanical Garden and Center for Plant Research).

UBC-Siska Research Goal: Addressing health and education needs through community-based revitalization of Ecological Knowledge and Practices with Traditional Food and Medicine Plants.

Saskatoon (s/cáqw-m) has been identified as one of the dominant shrub species in the harvesting area under the Siska Forest and Range Agreement. Through the Traditional Knowledge for Health Research Project, the Siska-UBC Research Team is conducting cross-generational community-based research and education that involves this food plant resource through a traditional food survey (dietary interviews and traditional food guide creation), harvest training research and education, traditional food practices (berry jam making that bridges youth-elder generations), and a youth traditional food interview video project.

Concurrently there is a non-UBC project underway (Siska Researchers, M Keefer & Teal Jones Group) that is designed to test different strategies for enhancing saskatoon and other key cultural plant species on sites that have been in decline (see: Measuring success in managing for Saskatoon berries and other traditionally important plants). Timber management in the area, and the absence of traditional management techniques such as pruning and fire has been hypothesized as being directly related to the decline. Ecologically, saskatoon is known to be a key browse species (ungulates and bears), and some experiments have been designed to enhance the resource for wildlife habitat. However, there is a gap in the literature concerning management of saskatoon stands for berry production as a traditional food resource. Results of the UBC-Siska and the Keefer et al. projects will be integrated for economic and food security in Siska Band, traditional use plant species abundance, improved harvest yields, biodiversity and compatible management of forests for berries and trees, climate change mitigation and wildlife enhancement.

The first two photographs show saskatoon in fruit and flower, while the third shows M. Keefer working with a Siska youth.

Here (PDF) are the proceedings of a workshop, which included Siska Chief F. Sampson, at Royal Roads University concerning native plants and First Nation people

Continuing the series for UBC Research Week, Connor introduces the next entry: Today we feature UBC Dept. of Forest Sciences Professor and Head, Robert D. Guy from the Faculty of Forestry. He shares with BPotD a collaborative project involving multiple labs.

Poplars Popular at UBC (an article from the Faculty of Forestry newsletter, Branchlines)

There is much interest in afforestation (PDF) as a strategy to help mitigate climate change by sequestering carbon and, ultimately, providing feedstock for renewable biofuels. These opportunities are likely to be greatest in intensively managed stands of rapidly growing trees. In Canada, there are several million hectares of marginal agricultural lands potentially available, mostly in the prairie provinces. But what’s actually available to plant? Not much it seems. Most of the available hybrid poplars currently planted in Canada are derived from species or populations adapted to relatively mild climates. While some of these "mild climate" clones are suitable to southern Ontario and southwestern British Columbia, few can survive on the prairies. There is, however, within our native forests, a tremendous untapped genetic resource, pre-adapted to the Canadian climate.

Ignoring aspens, Canada supports four of five North American poplar species. For example, balsam poplar is found in every province, from the US border to Inuvik, while black cottonwood occurs throughout British Columbia and adjacent areas of Yukon and Alberta. Appropriate selections and new hybrids could greatly increase the potential area that can be successfully planted to poplar.

Several researchers at UBC are studying genotypic variation in adaptive traits in poplar. To this end, some 750+ genotypes of balsam poplar (Populus balamifera) and black cottonwood (Populus trichocarpa), plus a wide selection of hybrids (including crosses with eastern cottonwood) are now springing up, in somewhat patchy fashion, at UBC’s Totem field (see photo). This “forest” might not last long, given the rate of campus development, but many of these genotypes grow so rapidly that if left uncontrolled there would be a continuous canopy within just a few years. Most of the clones come from two range-wide provenance collections – the BC MoF black cottonwood collection originally put together by Dr. C.C. Ying, and the new AgCanBaP balsam poplar collection compiled by scientists at the Prairie Farm Rehabilitation Administration (PFRA) Shelterbelt Centre, at Indian Head, SK. The AgCanBaP collection consists of some 15 individual clones from each of 43 populations.

So what are we doing with them at UBC? Several projects are underway or have been completed. In collaboration with Richard Pharis at the University of Calgary, Rob Guy and Shawn Mansfield (Faculty of Forestry) are investigating plant hormone profiles, fiber properties, carbon isotope composition, photosynthesis, and several other physiological parameters in black cottonwood, balsam poplar and various hybrids. This work forms the basis of thesis projects for Virginie Pointeau (Guy Lab) and Faride Unda (Mansfield Lab). In addition, Raju Soolanayakanahally (Guy lab) has been working closely with Dr. Salim Silim at the PFRA, both in Saskatchewan and at UBC, to characterize growth potential, photosynthetic rates, resource-use efficiencies and single-nucleotide polymorphism (SNP) variation in the complete AgCanBap collection. Using a subset of clones from the BCMoF collection, Hannah Buschhaus (Guy lab) recently completed her MSc thesis on variation in nitrogen isotope discrimination. Activity is not restricted to just the Faculty of Forestry. Quentin Cronk (Faculty of Land & Food Systems) and colleagues in Botany, for example, have been studying morphological variation, phenology and SNPs in the black cottonwood collection.

Physiology and other fancy stuff aside, the single most important attribute dictating the rate of biomass accretion is the length of the active growing season (i.e. the period from bud break to leaf drop). Timing of bud break in the spring is largely controlled by temperature. There is genetic variation in this trait but, in the main, when trees from different locations are planted in a common garden they generally flush out within a few days of each other. The same is generally true of cottonwoods, but a notable exception we’ve noticed at the UBC common garden is that trees from very high latitude can break bud in what we locally consider to be the depth of winter (December or January!). They also set bud several months too early (during our spring) because they are sensitive to the relatively short photoperiods encountered in Vancouver. Unlike bud break, bud set and (later) leaf drop are under tight photoperiodic control, and for these traits there are very strong latitudinal clines. In a common garden, genotypes from lower latitudes are in better synchrony with local conditions and remain active over a much greater portion of the available season, and they consequently accumulate far more biomass.

Although trees representative of northern populations generally do not grow as much as those from the south over any given summer, they can in fact possess higher photosynthetic rates. Indeed, they may also show the more rapid growth if measured over just a few weeks at the height of summer. We recently reported that light-saturated photosynthetic rates increased with latitude of origin in provenances of black cottonwood. This variation was well correlated with foliar nitrogen, stomatal conductance, and stomatal density.

The cline towards increased photosynthesis with latitude may be a generalised phenomenon among deciduous trees in North America. A similar trend is found in paper birch and Sitka alder and we see the same pattern in the AgCanBaP poplar collection. We speculate that northern provenances may have inherently high photosynthetic rates to compensate for the reduced leaf longevity associated with shorter growing seasons. Indeed, under an extended photoperiod in the greenhouse, where free growth is maintained, the fastest growing balsam poplar clones are from the far north. Clearly, the intrinsic growth rate must be assessed separately from the realized growth that occurs in a common garden. In other words, the largest individuals do not necessarily have the greatest growth potential if photoperiodic adaptation is unaccounted for. This raises the intriguing prospect of breeding trees from high latitude with trees of the same species from low latitude to combine high photosynthetic rates with a longer growing season. Using balsam poplar, such crosses have now been performed by collaborators at the PFRA and the “hybrid” progeny are undergoing assessment at Indian Head.

Fifth in a series celebrating UBC Research Week, again organized by Connor Fitzpatrick:

Scott Black, a Dept. of Botany M.Sc. student supervised by Dr. Gary Bradfield, and Hannes Dempewolf, a Ph.D. student co-supervised by Dr. Quentin Cronk and Dr. Loren Rieseberg, are researching the crop species noug, Guizotia abyssinica. Scott provided the photograph and Hannes adapted the write-up from this brochure on noug (PDF) that he co-authored (published by the Global Facilitation Unit for Underutilized Species).

What is noug?

Noug is an oil-seed crop, indigenous to Ethiopia and holds significant promise for improving rural livelihoods in Sub-Saharan Africa. The species is used in intercropping systems, grows on poor but also extremely wet soils, and contributes to soil conservation. While not fully domesticated, and suffering from low yields and susceptibility to insect herbivores, it contributes up to 50% of the Ethiopian oil-seed crop. Noug belongs to the Compositae family and is closely related to sunflower. It differs from domesticated sunflower mainly due to its high level of branching, numerous flower heads and small seeds. The oil content of noug seed varies from 30 to 50%. The fatty acid composition is typical for seed oils of the Compositae family with linoleic acid being the dominant component.

Ethiopia is well known as centre of diversity for several crops, including teff, enset and Ethiopian mustard. As a result, it has been suggested as Africa's independent origin of domestication. Noug diversity is greatest in Ethiopia and Eritrea and local farmers are able to distinguish many different land-races. The process of noug domestication is incomplete, probably due to frequent interbreeding with its co-occurring wild relatives. Apart from Africa (Ethiopia, Sudan, Uganda, Democratic Republic of Congo, Tanzania, Malawi, Zimbabwe), noug is also cultivated in parts of South Asia (India, Nepal, Bangladesh, Bhutan) where it was introduced several thousand years ago, and the West Indies.

The Rieseberg lab at UBC's Department of Botany is at the centre of an international collaborative research effort that has been launched in order to understand and manage the genetic diversity of noug for its improvement. The challenge of the project (2007-2010) is to show how modern molecular breeding efforts can be adapted and implemented for neglected and underutilized species, such as noug, through research on their diversity. This approach is especially powerful when conducted in the context of genomic information and tools that have already been developed for related major crops, in this case sunflower and lettuce.

This requires:

• collection, characterization and conservation of ecologically and genetically diverse germplasm
• initiation or re-orientation of existing breeding and crop deployment programs to capitalize on this diversity
• transfer of knowledge and technology to breeders and farmers in Ethiopia

With funds from the Canadian International Development Agency (CIDA), scientists from UBC's Department of Botany in collaboration with researchers from Addis Ababa University, the Ethiopian Institute of Agricultural Research and Bioversity International have initiated this project last year and have already completed several components, such as the collection and characterization of several noug cultivars in Ethiopia. Currently, scientists are working in the laboratory to assess the genetic diversity and population structure of noug and its wild relatives.

Today's entry, organized by Connor Fitzpatrick, is the fourth in a BPotD series for UBC Research Week. The photographs and write up come courtesy of Dr. Fred Sack, Professor and Head, Department of Botany.

Each leaf contains thousands of pores, stomata, which allow gas exchange between the atmosphere and the shoot. Stomata are cellular valves central to plant survival because they allow carbon dioxide to enter leaves where it is used to make sugars in photosynthesis. Stomata are also adaptive because they close down when water loss becomes too great. Efficient gas exchange seems to require that valves be spaced apart from each other since it is rare in nature to find two stomata in direct contact.

My lab pioneered the discovery of genes required for stomatal formation and spacing. We first determined how stomata develop and are distributed in the model eudicot Arabidopsis. As in all plants, stomatal formation requires an initial division that is unequal in size and fate, generating a smaller cell and a larger cell. After the smaller cell becomes oval in profile, it divides equally thus producing the two young guard cells that develop into the stoma. Meanwhile the larger cell produced by the unequal division can in turn divide asymmetrically. Normally this “piggyback” (iterative) division is oriented so that the new small precursor cell does not contact the previously formed one, a placement that generates the minimal one-celled separation between stomata. This placement probably requires intercellular communication, a conclusion reinforced when we identified the TOO MANY MOUTHS gene which encodes a probable receptor. Defects in TMM induce spacing violations, suggesting that it normally receives spatial cues used to correctly orient “piggyback” divisions. TOO MANY MOUTHS acts exclusively in the cells that form stomata as shown by the distribution of green fluorescent protein in the accompanying picture (red shows the cell walls; note that stomata are still forming in this picture; reproduced from Nadeau and Sack, Science). Thus this gene, which is conserved in monocots as well, controls the division behavior of islands of stem cells distributed throughout the epidermis of the developing shoot.

We also found that a different gene, FOUR LIPS, is required to ensure that there is only one equal division of the GMC (the guard mother cell is a precursor to guard cells). Mutations in FLP induce extra, abnormal, equal divisions resulting in four guard cells (lips) in a row (“stoma” comes from the Greek for “mouth”). We found that FLP is a transcription factor that regulates genes involved in cell cycling. Additional genes in this pathway are being identified in collaboration with Erich Grotewold at Ohio State University. It is likely that restricting GMC divisions to one (failsafe) would be strongly selected for in evolution since the control of water loss and the efficiency of carbon dioxide uptake are critical for plant survival.

The first photograph was taken using cryoscanning electron microscopy. The second photograph was taken using confocal laser scanning microscopy. The red channel shows the cell outlines (cell walls labeled with propidium iodide), and the green channel shows where the gene TMM is expressed.

Today's entry, organized by Connor Fitzpatrick, is the third in a BPotD series for UBC Research Week.

Loren Rieseberg, Professor and Canada Research Chair in Plant Evolutionary Genomics, conducts research on the genus Helianthus in his lab at UBC. Today's photographs of a hybrid sunflower species, Helianthus anomalus, are from the Little Sahara Sand Dunes in Utah, USA and taken by Jason Rick.

Prof. Loren Rieseberg has tapped the wild sunflower to explore a classic scientific question: How do new species emerge? To find out, his lab at the University of British Columbia marries molecular experiments with classic field studies to learn how radically different hybrid sunflowers arise and colonize new habitats.

Although scientists have long known that wild species hybridize — or mate with plants from different species — most believed that the resulting hybrids were maladjusted, evolutionary dead ends that quickly died out. However, over the past 15 years, Rieseberg has documented the rise of successful wild sunflower hybrids. His lab has compared the genes, physiology, and physical traits of five species: two widespread parental species, Helianthus annuus and Helianthus petiolaris, and three hybrid offspring that evolved between 60,000 and 200,000 years ago. Unlike their parents, the hybrid species — Helianthus anomalus (shown in the photos), Helianthus deserticola, and Helianthus paradoxus — favor extreme habitats: sand dunes, dry desert floor, and salt marshes, respectively.

To capture this evolution in action, Rieseberg's team replicated it by creating their own hybrids of Helianthus annuus and Helianthus petiolaris in the greenhouse. They analyzed the resulting neospecies for the adaptive traits — such as genes that confer salt tolerance or succulent leaves — needed to colonize the extreme habitats of naturally evolved hybrid species. Working with more than 2000 various synthetic hybrid seedlings, they successfully transplanted them in salt marshes in New Mexico and sand dunes or desert floor in Utah.

The DNA that drives hybrids is markedly different, too, Rieseberg and colleagues have shown. They used quantitative trait locus mapping — a method that taps molecular markers to find genes responsible for phenotypic traits such as leaf shape and seed size — to determine which combinations of alleles a plant has. Among sunflowers, the researchers confirmed that ordinary parent plants from temperate climates can indeed mate and yield hybrid offspring with hardier combinations of the same genes. These new gene combinations, they concluded, allowed the hybrids to colonize new ecological niches, such as salty and dry habitats.

From Brown, K. 2003. No garden-variety biologist. Science 302:1499.