No description available.

Copies of author's previously published articles inserted. Bibliography: leaves 128-143. This thesis describes the development of serological and nucleic acid based diagnostic methods for pea-seed borne mosaic virus (PSbMV), the isolation of specific effects on infected pea plants, the collection and biological comparison of new PSbMV isolates from Pakistan, the cloning and sequencing of specific parts of the genome of selected isolates, nucleotide and amino acid sequence comparisons between selected isolates, and the development of a ribonuclease protection assay (RPA) for identifying genomic differences among the PSbMV isolates. It is the first comparison of a range of geographically different isolates of PSbMV on the basis of both biological and molecular properties.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2000. / Restricted until November 2001. Bibliography: leaves 116-132.

Leguminous seeds are generally highly nutritious and have been used in the human diet for many centuries. The peasants of Asia and elsewhere grow leguminous seeds on small plots of land for their own consumption. The seeds are allowed to dry in the fields and are stored for use throughout the year. Dried seeds are either ground finely for use in baking or the whole seeds are boiled and used to make soups and curries. It has been known for centuries that seeds of the same variety may display variation in their cookability. The producer of commercial pea soups today is very aware of the variability in the cooking quality of his raw materials, as it may be necessary for him to change processing conditions to ensure the uniformity of the final product. [...]

No description available.

Intercropping of a short-cycle legume crop and a longer-cycle non-legume crop has been suggested as a potentially beneficial intercrop combination. Most studies have concerned cereal and legume corps. Few have involved horticultural crops. In 1990 and 1991, a 56-day semi-leafless pea crop (Curly) and a 75-day lettuce crop (Paris Island Cos) were grown both as monocrops and as intercrops. Intercrops consisting of alternating rows of each crop, represented additive populations (56:100) of peas and lettuce. Three lettuce transplanting dates (June 19, 25 and July 4) and three nitrogen fertilizer rates (0, 50, 100 kg ha$ sp{-1}$) were tested. Peas were all sown on May 18. In addition, a new pea/lettuce intercropping pattern (45:82), consisting of alternating double rows of peas and lettuce, was tested in 1991. The $ sp{15}$N dilution method was also used to test for nitrogen transfer. Alternate row intercropped lettuce plant$ sp{-1}$ yields were, on average, 76% and 46% lower than their corresponding monocrop yields for the early and late transplanted lettuce, respectively. Declines in yield of 63% and 55% were reported for the double row intercropped lettuce for the early and late transplanting dates, respectively. Nitrogen fertilization significantly improved intercropped fresh lettuce yields but had no effect on monocropped lettuce. Pea yields m$ sp{-1}$ row were unaffected by intercropping. Alternate row land equivalent ratios (LER) ranged from 0.87 to 1.05 and from 1.06 to 1.63, in 1990 and 1991, respectively. The double row LER's ranged from 1.06 to 1.21 in 1991. The higher LER's in 1991 reflected higher pea yields. No evidence of nitrogen transfer to the lettuce crop was detected.

No description available.

Total polyprenols prepared from Pisum stem and analyzed by HPLC, possessed chain-lengths equivalent to 15-17 isoprene units and were (alpha)-saturated. Pea membranes were supplied with GDP- ('14)C mannose, UDP- ('14)C GlcNAc and UDP- ('14)C glucose as substrates for glycosyltransfer in the presence or absence of added polyprenyl phosphates. Mono- and pyro-phosphorylated fractions were characterized using chromatographic and hydrolytic criteria. Glucosyl and mannosyl transfer took place to form endogenous polyprenyl-P-saccharide. Dolichyl-P was the only added polyprenyl phosphate which acted as an acceptor for these transferases. In contrast, incorporation of all the supplied sugars into polyprenyl-PP-saccharide was stimulated greatly in the presence of relatively short (alpha)-saturated polyprenyl phosphates, e.g., dihydro-heptaprenyl phosphate (7HP). A major product was 7H-PP-monosaccharide. / Oligosaccharide-lipids were also synthesized, all of which could be digested by treatment with endo H, indicating the presence of chitobiose. When UDP- ('14)C GlcNAc was used as substrate in the presence of dolP, labelled dol-PP-chitobiose was formed and then lengthened in the presence of unlabelled GDP-mannose. The same oligosaccharides were formed in experiments where the label was present in mannose. Evidence is presented for the further addition of terminal glucose to form "G" oligosaccharide. Endogenous levels of polyprenyl phosphates clearly limited the activities of pea transglycosylases, which were capable of recognizing isoprenoids of particular chain lengths and saturation patterns.

Graduation date: 1948

Graduation date: 1992