The present investigation is a study of the relationship between growth of Picea glauca. (Moench) Voss, Picea mariana (Mill.) B.S.P. and climatic influences. Special emphasis has been placed on a study of the relationship between summer temperatures and yearly and daily growth of the terminal shoot. The investigation was carried out at Knob Lake (also called Schefferville) in the center of the Labrador Peninsula during the summers of 1958 and 1959. [...]

No description available.

No description available.

In the present study the use of haploid plants and tissues was considered in relation to plant genetic manipulation. Haploid plants can be exploited directly, in the synthesis of true breeding lines. Alternatively, haploid plants and tissues may provide material for further experimentation involving protoplast fusion. Both approaches were investigated. Cyclamen persicum an attractive flowering plant is grown commercially from seed produced following open cross-pollination. As a result, Cyclamen is highly heterozygous, but the resulting variation is commercially undesirable. Inbreeding depression prevents the recovery of commercial inbred lines. Anther culture as an alternative approach for the recovery of true breeding lines was attempted. In order to test the efficiency of the culture procedure and conditions, anther culture of N. tabacum was also attempted, since this species is known to be highly responsive to anther culture. Despite the recovery of very many allodihaploid N. tabacum, plants from anther culture, no success was achieved with Cyclamen, and the possible reasons for this are discussed. It has recently been proposed that limited gene transfer might be achieved by somatic hybridisation if diploid protoplasts of a crop species were fused with haploid protoplasts of a wild type species, and novel allotriploid somatic hybrid plants recovered. Haploid protoplasts can be isolated from anther culture derived plants, however the range of species responsive to anther culture is limited. Tetrads, formed as a result of meiosis in the pollen mother cells, were investigated as an alternative source of haploid protoplasts for fusion studies. Somatic hybrids were recovered following fusion between N. tabacum leaf mesophyll (2n) and N. glutinosa tetrad (n) protoplasts. The somatic hybrids were fertile, and the progeny of the first backcross to N. tabacum were obtained. These results, and potential limitations to somatic hybridisation are considered in the context of plant breeding.

Screening of an En element population of Arabidopsis thaliana resulted in the identification of a mutant known as snakeskin (sks) in which the epidermal cell-cell linkages appear to be significantly perturbed (Marchant and Bennett, unpublished results). As a result of the breakdown of epidermal cell-to-cell linkages there are changes in epidermal cell architecture and distribution. These include alterations in pavement epidermal cell shape, stomatal distribution and trichome morphology. The defect in epidermal cell-to-cell adhesion may be a consequence of reduced cell expansion resulting in increased cell division as a compensation mechanism. This results in altered stomatal index and density and reduced root and hypocotyl elongation. A change in the ability of a cell to expand may be attributed to defects in cell wall composition or to the cytoskeleton that determines where the cell wall components arc localised during expansion. The sks mutant was found to have changes in its cellulose, xyloglucan and pectin fractions of the cell wall resulting in defects in cell wall adhesion, strength and expansion. To gain a greater understanding of the sks mutation the molecular basis of the SKS gene map based cloning was undertaken employing a combination of SSLPs, InDels and SNP markers. The SKS gene was found to be located on the bottom arm of chromosome 1 on BAC clone TIl 111. SALK insert lines have been utilised in a candidate gene approach in addition to fine mapping the mutation with SNP markers.

Thesis (M.Ag.Sc. 1974) from the Department of Agronomy, University of Adelaide.

Thesis (D.Sc.) -- University of Adelaide, Department of Botany, 1975.

Thesis--Bern. / Includes bibliographical references (p. 139-142).

Thesis--Belgrad. / Added t.p. and summary in Albanian and German. Bibliography: p. 241-[242].

Thesis (Ph.D.) - University of Chicago. / Bibliography: p. 116-119. Also available in print.