Plant Sciences Commons^™

Notes On Neotropical Amanoa (Euphorbiaceae), W. John Hayden

Biology Faculty Publications

Lectotypes are designated for Amanoa caribaea Krug & Urban and A. guianensis Aublet; presumed syntypes of the latter taxon are shown to be heterogeneous by inclusion of a previously unrecognized species. Four new species of Amanoa are described: A. congesta from French Guiana and northeastern Brazil; A. gracillima from Manaus, Brazil; A. nanayensis from Amazonian Peru and adjacent Colombia and Brazil; and A. neglecta from French Guiana and Surinam. Amanoa sinuosa is proposed as a new name for the later homonym A. robusta Leal. A key to the 13 neotropical species is presented.

The Short-Term Effects Of Manganese Toxicity On Ribulose 1,5 Biophosphate Carboxylase In Tobacco Chloroplasts, Kerrie Elliott

Masters Theses & Specialist Projects

The short-term effects of manganese toxicity on ribulose 1,5 bisphosphate carboxylase (Rubisco) activity and concentration in tobacco chloroplasts were examined. The activity of the enzyme from both manganese-treated and control plants was determined 6, 12, 18, 24 , and 48 h after introduction of manganese (80 mg/Li. Enzyme activity was determined by monitoring rates of radioactive CO₂ fixation into acid stable products. A slight stimulation of the enzyme's activity was noted in experimental plants after 18 h of exposure to manganese as compared with control plants. A decrease in the enzyme's activity in experimental plants was noted after 48 …

The Basis Of Browsing Tolerance In Shrubs Of The Intermountain West: Growth Rates And Meristematic Potential, Jackson L. Wandera

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Relative growth rates (RGRs) and meristematic potential of big sagebrush (Artemisia tridentata, in some experiments ssp. tridentata Nutt. and in other experiments ssp. vaseyana [Rydb] Beetls), bitterbrush (Purshia tridentata [Pursh] DC), serviceberry (Amelanchier alnifolia Nutt.), birchleaf mountain mahogany (Cercocarpus montanus Raf.), curlleaf mountain mahogany (C. ledifolius Nutt.) and big tooth maple (Acer grandidentatum Nutt.) were quantified under both glasshouse and field conditions. The relationships between the RGRs, meristematic potential and regrowth capacity of the shrub species were then determined. Sagebrush exhibited a significantly higher RGR than the other species at both high and low …

Methyl Salicylate Secretory Cells In Roots Of Viola Arvensis And V. Rafinesquii (Violaceae), W. John Hayden, John Clough

Biology Faculty Publications

The aromatic roots of Viola arvensis and V. rafinesquii were studied in order to determine the chemical nature and anatomical localization of their volatile compounds. Gas chromatography and mass spectroscopy revealed a single detectable volatile compound, methyl salicylate. Light microscopy and differential staining with Sudan III indicates the source of this compound to be enlarged secretory cells located in the endodermis, an unusual position for such cells in roots of angiosperms. The secretory endodermal cells are sporadic, but are more frequent in primary roots than in secondary roots and the lower portion of the hypocotyl. It is hypothesized that …

Monitoring Western Australia's Rangelands, Ron Hacker, David Beurle, George Gardiner

Journal of the Department of Agriculture, Western Australia, Series 4

Rangelands, native pastures used for grazing domestic livestock, occupy about 100 million hectares or 40 per cent of Western Australia, extending from the tropical grasslands of the Kimberley to the arid shrub steppe of the Nullarbor Plain.

The rangelands are characterized by highly variable seasonal conditions. Carrying capacity can fluctuate dramatically from year to year. Grazing management requires a tactical approach from one season to the next because of the great variation in the capacity of the land to support stock.

Rangeland monitoring provides pastoralists with objective information on these changes to assist their management decision making. The Western Australian …

Stratification Not Required For Tree-Of-Heaven Seed Germination, William R. Graves

William R Graves

Tree-of-heaven (Ailanthus altissima (Mill.) Swingle) seed germination and shoot dry weight were determined after stratifying samaras at 5 and 25 °C for up to 28 days. Seeds of samaras stratified at 5 °C for 0, 4, and 12 days showed 70, 77, and 96% germination, respectively, 7 days after sowing. Fourteen days after sowing, 90% of nonstratified seeds had germinated, but shoot weight of nonstratified seedlings was 16% less than that of seedlings from fruit stratified at 5 °C for 12 days. Germination 7 days after sowing was greater after stratification at 5 °C than at 25 °C, but the …

Additions And Corrections To The Rust Fungus Flora Of Minnesota, John W. Mccain

Journal of the Minnesota Academy of Science

Ten taxa of rust fungi (Coleosporium campanulae, Puccinia amphigena, P. caulicola, P.longipes var. brevipes, P. mcclatchieana, P. magnusiana, P.punctata var. troglodytes, Tranzschelia arthurii, Uromyces dictyosperma, and U. plumbarius) are reported for the first time from Minnesota. Seven other rust species (Puccinia adoxae, P. distichlidis, P. interoeniens, P. pygmaea, P. typhae, Uromyces andropogonis, and U. geranit) should be removed from the state flora list. Puccinia typhaealso is excluded from the U.S. rust flora list. New Minnesota host plants are reported for fifteen rust pathogens. One host species is deleted for P. polygoniamphibii. Intrastate 200-mile range extensions are reported for four rust …

Maine's Endangered And Threatened Plants, Maine State Planning Office

Maine Collection

Maine's Endangered and Threatened Plants

Executive Department, Maine State Planning Office, Critical Areas Program, 1990.

Evaluation Of Seeding Rates Of Au Triumph And Endophyte-Infected Kentucky 31 Tall Fescue, Jeffrey F. Pedersen, D. M. Ball

Department of Agronomy and Horticulture: Faculty Publications

Increased difficulty in stand establishment of tall fescue (Festuca arundinacea Schreb.) has been reported by producers since the introduction of endophyte (Acremonium coenophialum Morgan Jones and Gams)-free tall fescue seed into the market place. This has encouraged the use of higher seeding rates for endophyte-free tall fescue without scientific basis. The objective of this study was to determine whether ‘AU Triumph’, and endophyte-free cultivar, and endophyte-infected ‘Kentucky 31’ differ in minimum seeding rates for successful establishment. Experiments were established at two locations in each of two years, using a randomized complete block with four replications. Soils at the two locations …

Waterlogging : How It Reduces Plant Growth And How Plants Can Overcome Its Effects, Tim Setter, Bob Belford

Journal of the Department of Agriculture, Western Australia, Series 4

Lack of oxygen is the major cause of limited plant growth in waterlogged soils. When soils become waterlogged less gas diffuses to and from the roots through the soil pores; there are changes in concentrations of mineral elements in soil solutions; and toxic products of roots and soil microorganisms begin to accumulate. These changes adversely affect germination, growth and development of plants.

Sexual Dimorphism And Intersexual Differences In Resource Allocations Of A Dioecious Shrub, Lindera Melissifolia (Walt.) Blume, Dennis J. Richardson, Robert D. Wright, Shannon Walker

Journal of the Arkansas Academy of Science

Morphometric data were gathered to make intersexual comparisons on the morphology and reproductive resource allocation patterns of the rare, dioecious shrub, Lindera melissifolia. Females produced significantly fewer flowers and leaves than did males. No other significant differences could be detected in morphology. Female "clones" exhibit low area coverage and low stem density, which suggests higher costs of reproduction. If this is the case, the deficits produced in resource allocations directed toward sexual reproduction seem to result in increased mortality and/or reduced vegetative reproduction.

Fescues With Large Roots Are Drought Tolerant, H. A. Torbert, J. H. Edwards, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Consideration of root/soil interactions is essential in, adapting tall fescue (Festuca arundinacea Schreb.) to soil and climatic conditions of the Coastal Plain region of the southeast. Sandy soils of the region are very susceptible to the formation of hardpans. These compacted layers often restrict plant root development to the plow layer (0 to 6 in.) and prevent plant roots from reaching available moisture and nutrients in the subsoil horizons. Plants grown under these conditions are shallow rooted and will be subjected to water stress up to 50% of the time during the growing season. Although implements are available to penetrate …

A Review Of The Agronomic Characteristics Of Endophyte-Free And Endophyte-Infected Tall Fescue, Jeffrey F. Pedersen, G. D. Lacefield, D. M. Ball

Department of Agronomy and Horticulture: Faculty Publications

Agronomic differences between endophyte- (Acremonium coenophialum Morgan Jones and Gams) free and endophyte-infected tall fescue (Festuca arundinacea Schreb.) exist, and should be considered when implementing a management strategy. Although dry matter yield of tall fescue does not generally appear to be influenced by endophyte infection status, endophyte infection has been shown to improve seedling performance and survival, is associated with insect and nematode resistance, drought resistance, improved nitrogen assimilation, and higher seed set. Considering all biologically valuable characters of the endophyte-tall fescue relationship, survival of endophyte-infected tall fescue is probably better than that of endophyte-free tall fescue, especially in drought- …

Heritability Of Root Characteristics Affecting Mineral Uptake In Tall Fescue, J. H. Edwards, Jeffrey F. Pedersen, R. C. Kingery

Department of Agronomy and Horticulture: Faculty Publications

Modification of plant roots can potentially increase the area. of adaptation of tall fescue (Festuca arundinacea Schreb.). Limited information is available on the heritability of root diameter and root volume in tall fescue. A greenhouse experiment was conducted with'50 random 'Kentucky 31' (Ky-31) tall fescue parents and their progeny grown in aerated nutrient solution during four separate time intervals. Measurements of root volume, root diameter, shoot Mg concentration, and shoot K/(Mg + Ca) ratio were made six weeks after clonal material was transplanted in nutrient solution. Heritability estimates for root volume, root diameter, shoot Mg concentration, and shoot K/(Mg …

Biological Control Of Doublegee, Dane Panetta

Journal of the Department of Agriculture, Western Australia, Series 4

Doublegee (Emex australis) is one of the worst agricultural weeds in Western Australia. To date, however, biological control of this weed has proved elusive. Multiple releases of two weevils which attack doublegee have not led to insect establishment. For one of these species, further research has shown that doublegee control would probably not be achieved in the wheatbelt even if insect establishment were enhanced by growing its host during the summer months. A joint Western Australian Department of Agriculture/ CSIRO project is investigating the virulence and host specificity of an undescribed South African species o/Phomopsis fungus. Should this pathogen prove …