Yuguang Bai

University of Saskatchewan | U of S · Department of Plant Sciences

Our previous study showed that smoke derived from alfalfa ( Medicago sativa ) caused different germination responses compared with that from prairie hay ( Festuca hallii ) and wheat straw ( Triticum aestivum ), but the mechanism remained unclear. In this study, we used Salad Bowl lettuce ( Lactuca sativa ) as a quick bioassay to trace the active co...

The success of a biological invasion relies on the environment and is closely linked to factors such as water and temperature. Invasive plant species display different seed characteristics, including shape. Field sandbur (Cenchrus pauciflorus) is a globally widespread invasive species capable of adapting to broad environmental conditions. However,...

Growth character of field Cenchrus pauciflorus. (A) seed, (B) seedling, (C) population, (D) spiking in the field, (E, F) spiking in different stages, (G) maturity, (H, I) whole single plant. (TIF)

Measurement of M and P seeds of Cenchrus pauciflorus. Seed length, width and thickness are marked with line AB, line CD and line EF, respectively. (TIF)

Characteristic of M and P seeds of Cenchrus pauciflorus. Lowercase letter indicates significant difference between M and P seed at P< 0.05. (DOCX)

Fire plays a crucial role in mediating species composition in Fescue Prairie. However, previous studies focused on responses of plant community to burning without disentangling the effects of burning on seedling emergence in Fescue Prairie. In this study, seedlings emerging in the field and from soil seed banks incubated in a greenhouse were examin...

Plains rough fescue (Festuca hallii [Vasey] Piper) is an important, native forage grass species in Western Canada. Despite the high demand of seeds of this species, supply remains extremely limited mainly due to erratic seed production in native prairies. The underlining physiological and environmental principles remain largely unknown. Using histo...

Little is known about how smoke, an important germination cue, influences seed regeneration of species in Fescue Prairies. Whether germination and seedling growth responses vary with smoke produced from different materials is still ambiguous. In this study, seeds of four forbs from a Fescue Prairie were primed in serial dilutions of aqueous smoke s...

Seedling recruitment plays a crucial role in recovering plant communities after disturbance. As a natural disturbance, fire canmediate species composition in fescue prairie. However, little was known about the effects of important fire cues on seedling recruitment in fescue prairie. Soil seed bank samples were taken fromthe top 5 cm of the soil pro...

Seeds of many forage species have dormancy, delaying germination in the field. Species from semi-arid environments may have adaptation to fire, therefore, the effects of priming seeds of common forage species in aqueous smoke solutions were studied. Seeds of eight grasses and two legumes were primed in serial dilutions of aqueous smoke solutions an...

Plains rough fescue (Festuca hallii [Vasey] Piper) is an important forage grass species in the Northern Great Plains of Canada. Its seed is in demand for forage production and habitat restoration, but erratic seed production limits supply. A comprehensive understanding of factors influencing flowering and seed production in this species is needed....

Seed mass is an adaptive trait affecting species distribution, population dynamics and community structure. In widely distributed species, variation in seed mass may reflect both genetic adaptation to local environments and adaptive phenotypic plasticity. Acknowledging the difficulty in separating these two aspects, we examined the causal relations...

Correlations in seed mass with latitude, longitude and altitude for black spruce (a, b, c), white spruce (d, e, f) and jack pine (g, h, i) across the Canadian Boreal Forest and within major ecozones. Only significant correlations were presented. * p≤0.05, ** p≤0.01, *** p≤0.001. (DOCX)

Unstandardized path coefficients, standard error of the unstandardized coefficients, tests of path coefficient significance, and standardized path coefficients from the observed variable model in Fig. 2. Variable names are explained in the legend of Fig. 2. Standardized path coefficients are in standard deviation units and are primarily used to com...

Correlation coefficients (r) between seed mass and climatic variables for black spruce, white spruce and jack pine in the Canadian Boreal Forest. (DOCX)

Initial pathway models for seed mass for black spruce, white spruce and jack pine. Variables are explained in the caption of Fig. 2. (DOCX)

Correlation coefficients (r) between geographical variables for black spruce, white spruce and jack pine in the Canadian Boreal Forest. (DOCX)

Much of the remaining native rangelands in Canada are topographically complex. The flux of greenhouse gases (GHGs) in rangelands of hummocky terrain has not been adequately studied, leaving a gap in the national GHG sources and sinks budget. The objectives of this study were to determine the effects of topography and mowing on carbon dioxide (CO2),...

The ponderosa pine and Douglas-fir forests in the Interior of British Columbia, Canada, are facing problems such as forest in-growth mainly due to fire suppression, reducing grazing land area. This study focused on the use of thinning to reduce forest stand density and restore understorey species diversity and increase aboveground biomass productiv...

The interactions between adjacent trophic levels are essential for ecosystem functioning and stability. Grazing by domestic herbivores is an essential interaction in grasslands, but little information is available on the nature of relationship between plant and insect diversity under grazing by large herbivores. We examined the effects of large her...

Background/Question/Methods: The effects of global change conditions on seed germination and plant regeneration have been reported in many species. However, there are no consistent trends within and among plant functional groups (C3 vs C4) regarding how seed quality and germinability are affected by these climate change conditions. Seeds of three...

Pantel, A., Romo, J. T. and Bai, Y. 2011. Above-ground net primary production of plains rough fescue [Festuca hallii (Vasey) Piper] after a single defoliation on five landform elements. Can. J. Plant Sci. 91: 689-696. Above-ground net primary production (ANPP) was determined for plains rough fescue [Festuca hallii (Vasey) Piper] following a single...

Above-ground net primary production (ANPP) of northern wheatgrass (Elymus lanceolatus [Scribn. & J. G. Sm.] Gould) and western porcupine grass (Hesperostipa curtiseta [Hitchc.] Barkworth) was determined after defoliation to a 7.5 cm stubble height on five landform elements in the Northern Mixed Prairie that had been ungrazed for . 25 yr. Landform e...

Native plants have adaptations to their local environments and elucidation of these traits has implications in both agronomy and restoration ecology. Winterfat (Krascheninnikovia lanata (Pursh) A.D.J. Meeuse & Smit) is a native perennial shrub in North America capable of germinating at low temperatures. The effect of seed size on germination abilit...

Timing of seed germination influences plant lifetime fitness and can affect the ability of plant populations to colonize and persist in changing environments. However, the genetic variation of the seed germination response remains poorly understood. The amplified restriction fragment polymorphism (AFLP) technique was applied to characterize the gen...

Close spatial relationships between plant species are often important for defense against herbivory. The associational plant defense may have important implications for plant community structure, species diversity, and species coexistence. An increasing number of studies have focused on associational plant defense against herbivory at the scale of...

Background/Question/Methods Festuca hallii (Vasey) Piper is a native perennial grass in Western Canada. There has been an increasing demand for seeds of this species for habitats restoration and forage production, but seed production in native prairies occurs only once every 5-10 years. Preliminary analysis on the relationship between weather patte...

Resting plants after grazing is central to sustaining potential plant production. Growth of graminoids and forbs was determined for 3 yr after a single defoliation to 7.5 cm in May, June, July, August, September, October, November, or April on five different landform elements in the Northern Mixed Prairie. Green standing crop and cumulative green s...

Grassland in North America is expected to expand northward as the climate becomes warmer and drier under many climate change scenarios. Successful adaptation of plant species to climate change depends on regeneration success. This paper aims to identify the spatial variation in seed germination characteristics of Festuca hallii populations and to q...

Genetic diversity is essential for predicting plant evolutionary potential and for formulating conservation strategies. However, little is known about the genetic variation of plains rough fescue [Festuca hallii (Vasey) Piper], a widespread and diagnostic grass in the Fescue Prairie. We used the amplified fragment length polymorphism (AFLP) techniq...

Aerial expansion of woody species in grasslands is common in arid and semiarid areas. The ecological consequences of shrub expansion, including ecosystem function and carbon sequestration, are complex and dependent on local environmental conditions. This research was conducted in the Northern Mixed Prairie of Canada to determine the effects of west...

Spatial distribution of food resources is an important factor determining herbivore foraging. Previous studies have demonstrated that clumped distribution of preferred species increases its consumption by herbivores in single- or two-species systems. However, the potential impact of distribution pattern of less preferred species on foraging was ign...

Tree encroachment in the ecotone between grassland and forest of interior British Columbia has resulted in decreasing grazing potential of rangelands. The 2 dominant tree species in this region, Douglas fir (Pseudotsuga menziesii var. glauca) and ponderosa pine (Pinus ponderosa), require stratification for seed dormancy release. The objective of th...

Los pastizales en el interior de Columbia Británica en Canadá están adyacentes a los bosques y son susceptibles a la invasión por árboles. El apacentamiento, la supresión del fuego y la variabilidad climática están entre los factores que afectan la dinámica de la vegetación en el ecotono entre el pastizal y el bosque, pero los factores topográficos...

Tiny cryptanthe (Cryptantha minima Rydb.) is an endangered annual plant adapted to prairie sand dunes of Canada. Thermal time and hydrothermal time models were used to quantify the effect of temperature and water potential on seed germination and to relate it to field conditions. Tiny cryptanthe seeds had a base temperature of −3.9 °C for germinati...

Ponderosa pine Pinus ponderosa and Douglas-fir Pseudotsuga menziesii forests in the Interior of British Columbia, Canada, are adjacent to grasslands. Forest ingrowth and tree encroachment, mainly due to fire suppression, represent threats to both forest and ranching industries in the region. The use of prescribed burning for ecological restoration...

Punagrass (Achnatherum brachychaetum (Godr.) Barkworth) and flechilla grande (Nassella clarazii (Ball) Barkworth) are perennial grasses native to Argentine grasslands, with contrasting life history strategies. Both species have seed heteromorphism, but punagrass is an invasive whereas flechilla is a climax species. Experiments were conducted to det...

Herbivory and resource interact to influence plant regrowth following grazing, but few detailed investigations on grazing tolerance at population levels are available. We conducted two pot experiments along a simulated grazing gradient (0%, 25%, 50% and 75% of shoot removal) at three water or nutrient levels to determine the interaction of resource...

Seed germination and seedling emergence of ‘Arctic’ and ‘Lineta’ orchardgrass (Dactylis glomerata L.) and ‘Walsh’ and ‘LC9078a’ western wheatgrass (Pascopyrum smithii [Rydb.] L.) were studied both in the field and laboratory. Four seeding dates were conducted each year over 2 years and seedling emergence and seed fate in the soil were monitored. Th...

Plains rough fescue (Festuca hallii (Vasey) Piper) is a dominant native grass species in the Fescue Prairie region of North America that has undergone dramatic range reduction in the past century. Little is known about the genetic diversity of this species. The amplified restriction fragment polymorphism (AFLP) technique was applied to assess the c...

A natural grassland in northeastern China dominated by Leymus chinensis (Trin.) was subject to drought treatments to determine the seasonal dynamics in resource partitioning to shoot and storage organs in response to drought. The growing season was divided into six stages according to the phenology of L. chinensis. Plant samples of L. chinensis wer...

The effects of alternating temperatures on seed dormancy changes, germination and seedling emergence were investigated in ‘Arctic’ and ‘Lineta’ orchardgrass (Dactylis glomerata L.). Thermal time models were successfully developed for 0, 5, 10 and 15°C temperature amplitudes, using 28 constant and alternating temperature regimes. These models were t...

Photosynthetic pathways (e.g. C3, C4) and morphological functional types (e.g. trees, shrubs, high perennial grasses, perennial forbs) were identified for the native species from the Saskatchewan mixed prairie, using the data from references published between 1950 and 2003. Of the total 219 identified species in 145 genera and 45 families, 208 spec...

Winterfat is a native shrub in the prairies of North America and seedbed conditions determine seedling establishment and population restoration. Thirteen seedbed treatments were created with 2–3 sowing dates and irrigation levels in the field over 2 years to quantify the effect of soil temperature and water potential on seedling emergence. Seedling...

Winterfat (Krascheninnikovia lanata) (forage seed) is a long-lived native shrub with superior forage quality for livestock and wildlife. The objectives of this study were to use advanced synchrotron technology [S-Fourier transform infrared microspectroscopy (FTIR)] as a novel approach to reveal protein molecular structural-chemical differences in t...

Tree covers in the ecotone between forest and grasslands of British Columbia (BC) vary from less that 15% to over 35% and have increased in the last century. Recent developments in remote sensing focus on high resolution, multi-spectral digital images. For the detection of historic changes in tree cover, however, black-and-white aerial photographs...

Net photosynthetic rate (P N), transpiration rate (E), and stomatal conductance (g s) declined from upper leaves to the lower ones during dry and rainy seasons, indicating that long-term carbon budget should take into account P N variations for different leaf types. Relatively greater P N in the dry season suggested that this species is more able t...

The hydrothermal time model not only quantifies seed germination progress as affected by temperature and water potential, but also has ecological and biological significance. Assumptions of the hydrothermal time model were tested using two non-dormant seed collections of winterfat (Eurotia lanata) with two seed size classes. Winterfat is a native s...

Thermal time has been widely used to quantify and model seed germination. However, several assumptions in the thermal time model remain untested. The purpose of this study was to test variations in parameters of the thermal time model among seed size classes and sub-zero imbibition-temperature treatments using two non-dormant seed collections of wi...

Many range managers have suggested that clubmoss (Selaginella densa Rydb.) negatively alters the composition of seed banks and inhibits the establishment of plant species that decrease under improper grazing management. Alternatively it is possible that soil seed banks contain few seeds of decreaser species and composition of the seed bank is indep...

Demand for sagebrush seed is expanding, but wildland harvesting is impaired by several factors including loss of stands to weed invasions and fire. To increase the potential for seed produc-tion, sagebrush seed harvests were compared among cultural treat-ments for stands on a coal mine near Glenrock, WY. Sagebrush in the study were mature plants on...

Parental conditions, such as temperature, soil moisture, nutrient availability, light and competition during plant growth and seed maturation, influence seed quality and germinability. Elevated CO2 concentration can be also treated as a parental condition and should be considered when evaluating crop productivity under future climate conditions. Av...

Wyoming Coal Rules and Regulations require shrubs be returned to mined land and that revegetation "...be self renewing." We evaluated seed production and seed quality of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis (Beetle & Young)) by measuring the effect of mining, herbivory, and environmental modification on seed productio...

Although the maintenance of biodiversity has become one of the goals in ecosystem management, the relationships of diversity to ecosystem characteristics such as level of herbivory, productivity, and vegetation structure are still poorly understood, We examined these relationships in 8 native grassland sites differing in grazing histories and range...

Grasslands of interior British Columbia are being encroached upon by Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) France) and ponderosa pine (Pinus ponderosa Dougl.). A pot experiment placed in the field was conducted to determine the effect of forest and grassland seedbeds on seedling emergence and early establishment of the 2 species...

Success with Wyoming sagebrush (Artemisia tridentata ssp. wyomingensis) depends on good seed vigor, and rapid seedling development. These characteristics are influenced by harvesting, processing, storing, and sowing. In this paper we discuss research findings related to those activities: (1) It appears that Wyoming big sagebrush growing on the west...

The robustness of competitive attributes of cereals such as rapid and uniform seedling emergence, tillering, early biomass accumulation and canopy closure, and height advantage over weeds have not yet been tested under environmental conditions typical of no-till (NT) cropping systems. Our objective was to evaluate the effects of NT practices on gro...

Inhibition at cold temperatures reduces seedling vigor of some species, but is beneficial to others. We used 3 rangeland shrubs and 8 agronomic crop species to test for a general relationship between imbibition temperature (5 to 30°C) and seedling vigor measured as post-germination growth; and to test for an effect of imbibition temperature on seed...

Winterfat [Krascheninnikovia lanata (Gueldenstaedt) syn. Ceratoides lanata (Pursh) J.T. Howell, syn. Eurotia lanata (Pursh) Moq.] is a native shrub of mixed prairie of North America. A large portion of hydrated seeds and seedlings can be killed when exposed to seedbed desiccation. Winterfat seeds and young seedlings subjected to varying levels of d...

Sagebrush (Artemisia) is commonly recommended for reclamation and restoration of shrublands of the Western United States and seeds are usually obtained from commercial sources. One result of commercial seed processing is the removal of the pericarp. We tested 2 seedlots of Wyoming big sagebrush (A. tridentata Nutt. ssp. wyomingensis Beetle & Young)...

Winterfat (Eurotia lanata (Pursh) Moq.) diaspores harvested from 1 Canadian and 2 USA sites were imbibed at 0, 5, 10, and 20°C. It was hypothesized that imbibition temperature affects seed hydration which is related to cold-hardiness of winterfat. Weight gain was measured at 8-hour intervals until full hydration, and embryo water content was determ...

Diaspores of winterfat (Eurotia lanata (Pursh) Moq.) collected from 2 locations in the USA and 1 in Canada were imbibed at 10° C and grown to 4 different developmental stages (2, 3, 6, and 14 days of incubation), then subjected to cooling temperatures as low as -30°C. Differential thermal analysis was used to detect exotherms associated with ice cr...

Thermal analyses of freezing events in hydrated lettuce ( Lactuca sativa L.) seeds show a correlation between low temperature exotherms (LTEs) (evidence of ice crystal formation) and seed death. Yet, weather patterns common to the Northern Great Plains of North America regularly create conditions where non-dormant seeds of native plants hydrate wit...

An accurate determination of moisture content in hydrated or partially hydrated seeds is fundamental to understanding early physiological processes in seeds, and the associated environmental interactions that affect seedling vigor, establishment, and survival. One difficulty encountered while measuring the moisture content of imbibed seeds is that...

The Northern Great Plains grasslands evolved under natural disturbances such as fire, drought and grazing. Since European settlement, fire has been minimized or eliminated and bison have been replaced by domesticated livestock. It is not clear, however, how grazing by livestock affects grassland ecosystem parameters such as species diversity and pr...

Seed germination and seedling vigor of Wyoming big sage-brush (Artemisia trident&a Nutt. ssp. wyomingends) were evalu-ated following manipulation of seed moisture, a practice benefit-ing many species. At the time of harvest, seed moisture ranged from 2.3 to 9.0% for 5 collections tested and seeds with moisture between 5 to 6% had the highest and mo...

Increases in fringed sagebrush (Artemisia frigida Willd.) following disturbance on Northern Mixed Prairie are due to enhanced growth of established plants and seedling recruitment. The roles of seed production and the soil seedbank in population dynamics of fringed sagebrush following disturbance are, however, unknown. Furthermore, seed rain has no...

Debearders are machines originally developed to remove grain from bearded (awned) seed heads of small grains. They are now used in many types of seed cleaning, including preparing sagebrush seed for market. Some people have suggested that debearders may decrease sagebrush seed quality. We tested this hypothesis by using a debearder to process seeds...

Fringed sagebrush (Artemisia frigida Willd.), the most common dicotyledonous species in the Northern Mixed Prairie, often increases dramatically following disturbance. It was hypothesized that the increase could be due to release of established plants, increased recruitment of plants, or both. Experiments were conducted on a sandy range site in cen...

Seeds (achenes) of fringed sage were collected in central Saskatchewan in 1987, 1990, and 1991, and studies were conducted to determine the effects of imbibition time before brief or prolonged exposure to red (R) and far-red (FR) light on germination. A majority of the seeds required light for germination, but a substantial proportion germinated in...

Experiments were conducted to determine the influences of temperature, light, winter storage, and water stress on seed germination of fringed sage. Seeds collected in 3 yr in central Saskatchewan were placed in sealed vials and buried in the soil after harvest, and germination was tested in spring and early summer. Seeds germinated over a wide rang...

Seedlings of Artemisia frigida emerged only when soil moisture was above −1·5 MPa and total emergence increased with the total amount of water supplied. Regardless of the watering regime, A. frigida required a minimum of 8–10 days before emerging at 10°C and approximately 60 mm cumulative moisture to reach stable maximum emergence. When precipitati...

Seeds of fringed sage were collected in four different years in the Northern Mixed Prairie and placed in sealed vials in the field for up to 5 yr. The seeds were exhumed monthly and incubated at 10 or 20 C in light or darkness. Germination was greater at 10 than 20 C and greater in light than darkness. The overriding influences of light and tempera...

Thesis (Ph. D.)--University of Saskatchewan, 1994. Includes bibliographical references.