Thesis - University of Lund. / Bibliography: p. 8.

Thesis (Ph. D.)--University of Chicago, 1912. / "A Private edition distributed by the University of Chicago Libraries." "Reprinted from the Botanical Gazette, Vol. LXIII, No. 5, May 1917." "Literature cited": p. 371-372. Also available on the Internet. Also issued online.

Thesis (Ph. D.)--University of Chicago, 1921. / "Private edition, distributed by the University of Chicago Libraries, Chicago, Illinois." "Contributions from the Hull botanical laboratory 288." "Reprinted from the Hull botanical gazette, vol. LXXII, no. 6, December, 1921." "Literature cited": p. 373-374.

The N-end rule pathway of targeted proteolysis is regulated by Group VII ethylene response factors (ERFVII’s). The aim of this research work was to analyse the relationship between substrates (ERFVII’s) of the N-end rule pathway and genes, which have promoters containing a double ‘GCCGCC’ Ethylene-Responsive Element Binding Protein (EBP) cis-element. Several genes were identified containing double EBP elements. Cloning and transformation of the promoters from five of these genes (PYL, ERD4, AT1G14810, AT3G13440 and AT5G44420) carrying two copies of the GCC-boxes present in the 5' UTR (5’ untranslated region) or promoter region was conducted into Arabidopsis wild-type (Col-0) and prt6-1 mutant plants. Expression driven by these promoters in the leaves and flowers of transgenic plants was analysed through GUS staining to reveal promoter activities. Enhanced promoter activity was seen in prt6-1 lines (mutated in the E3-ligase of the N-end rule pathway) in comparison to Col-0. Further, cDNA of leaves and flowers of Col-0 and prt6-1 were analysed by q-RT-PCR (quantitative real-time PCR) for expression of PYL7, ERD4, AT1G14810, AT3G13440; t-test analysis showed a significant difference (p-value<0.05) only in leaves of Col-0 and prt6-1 for PYL7. Analysis of the genetic relationship between N-end rule pathway and genes containing GCC-boxes was also performed by analysing double mutant combinations of prt6-1 and mutants of genes containing the EBP elements (pyl7prt6-1, erd4prt6-1 and abi5prt6-1) and Col-0 under different concentration of salt to determine the effect of stress due to salinity on the regulation of genes. At 125mM salt concentration significant difference was identified in highest number of mutant lines in comparison to Col-0. An analysis of the in-vivo binding of the ERFVII RAP2.3 to the promoter of GCC-boxes containing genes was performed through Chromatin Immuno-precipitation assay (ChIP). The t-test analysis on qChIP-PCR data indicated significant difference between IgG and HA-IPs for both ABI5 and PYL7 performed on normoxic 35S:MA-RAP2.3-HA in Col-0 line. Further, in-vivo localization of ERFVII’s HRE1 and RAP2.2 conditional stability was analysed using promERFVII’s:MC/MA-ERFVII’s-YFP constructs in Col-0 and prt6-1. This thesis suggests that genes PYL7, ERD4, AT1G14810, AT3G13440 that have double ‘GCCGCC’ EBP elements are downstream targets of the N-end rule pathway. Further analysis via ChIP suggests that RAP2.3 interacts with the ‘GCCGCC’ binding site of promoters in the ABI5 and PYL7 genes, however further work is needed to confirm this. Additionally, sub-cellular localization of promERFVII’s:MC/MA-ERFVII’s-YFP studies suggest the location of HRE1 and RAP2.2 in nuclei of early stage root tips studied on 4-days old etiolated seedlings.

The vegetation of an area of 6000 sq.miles was studied in two stages: 1. a reconnaissance survey of a typical part to obtain general information on the distributions of the communities; 2. detailed investigations of a large number of small areas to obtain data on the interrelations of communities and habitats. The following procedure for mapping vegetation from aerial photographs is described in detail: 1. Stereoscopic interpretation of the aerial photographs. 2. Assembly of the detail to produce semi-controlled mosaics of air-photo patterns. 3. Planning and execution of traverses to sample the vegetation represented by each air-photo pattern. This procedure was used in the Reconnaissance Survey and maps on the scale 1: 50,000 were produced of the vegetation of 800 square miles. It was concluded that the distribution of vegetation types within the reconnaissance area is controlled by topography through its effects on soil type and drainage, and by burning and cutting. The Detailed Investigation was based on the phytosociological and ecological data of 174 sites located throughout the North Mengo Lowlands. It is shown that the distributions of the different communities found in this region are determined by one or more of the following factors: fire and the occurrence of fire breaks; soil type, nutrient status, texture, structure, and drainage; cutting and cultivation; climate; and the degree of uniformity imposed on the environment by the dominant species or the vegetation as a whole. While certain factors control the distribution of each community no one factor or group of factors is responsible for the distributions of all the communities in the North Mengo Lowlands. The distributions of soil types in catenary complexes were noted during the Reconnaissance and were later seen to extend over the whole of the North Mengo Lowlands. The other data of the Detailed Investigation also indicate that the reconnaissance area is typical of the whole region. Comparisons of the data of sites within each of the types mapped during the reconnaissance shown that some of those types are not significantly different either in respect of their communities or their habitats; and also that certain areas have been mapped incorrectly. However, it is indicated that the 1:50,000 maps could be revised by merging areas of the overlapping types. Modifications to the procedure are suggested to attain greater accuracy.

Carbohydrate metabolism and heterotrophic carbon fixation have been studied in the intertidal macrophytic brown algae Pelvetia canalioulata and Fucus spiralis. In neither of these species can the heterotrophic metabolism of glucose support net growths. Photosynthetic rate, however, is enhanced by over 40% in Pelvetia in the presence of exogenous glucose. It is postulated that this glucose lowers the light requirement for photosynthesis rather than acting as a substrate for significant levels of heterotrophic carbon fixation.

Root architecture governs the uptake of water and nutrients from the soil and thus is essential for plant growth and survival. The control of lateral root branching is a crucial aspect of determining root architecture, and is a process largely controlled by the phytohormone auxin, which promotes lateral root organogenesis from founder cells within the vasculature and also subsequent lateral root elongation. A small posttranslationally modified peptide, CTERMINALLY ENCODED PEPTIDE1 (CEP1) is a bioactive 15-amino acid peptide cleaved from a larger precursor protein previously shown to negatively affect primary root elongation and lateral root branching in Arabidopsis thaliana. Within this thesis, genetic, biochemical and pharmacological approaches are used to demonstrate that another member of the CEP family, CEP5, reduces primary root length and negatively regulates lateral root branching in Arabidopsis thaliana with minor effects on aboveground architecture. CEP5 is also demonstrated to have an antagonistic relationship with auxin, with increased abundance of CEP5 leading to downstream stabilisation of the auxin signalling repressor AUXIN/INDOLE ACETIC ACID (AUX/IAA) proteins. Correspondingly, reduced abundance of CEP5 increases auxin responses, including enhanced lateral root progression. These studies suggest CEP5 regulates lateral root branching through attenuation of auxin responses.

It is thought that climate change will have a major impact on species distributions by changing the habitat suitability for species. Species distribution modelling is a modern approach to assess the potential effect of climate change on biodiversity. We used 11 environmental variables with the MaxEnt algorithm to model the distributions of 114 Egyptian medicinal plant species under current conditions, then projecting them into three different future times (2020, 2050, and 2080) under two different climate-change emission scenarios (A2a and B2a), under two hypotheses about the capability of the species for dispersal (unlimited and no dispersal). Species richness maps for current and future times were produced. We tested the value of Egypt’s Protected Areas under climate change by estimating the species richness inside and outside under each scenario. We assessed Egyptian medicinal plants based on IUCN Red List categories and criteria, and then used the SDMs for conservation planning with and without consideration of socioeconomic factors using Zonation software. The A2 emission scenario was more harmful than B2 under all assumptions. Species richness inside Protected Areas was significantly higher than outside for all models. Based just on the records, between 75% and 90% of species could be classified as Least Concern, according to the assumptions made. Similarly, based on SDMs all species could be classified as LC at the current time, whilst in the future under climate change, up to 18% of species face the risk of extinction, depending on assumptions and based on the absolute time gap between the two future times. Based on 10 years, most species were assigned as Least Concern. Areas within PAs were no better in conservation prioritization value than area outside when socioeconomic costs (especially the Human Influence Index) were taken into account. Species distribution models appear to be extremely useful for conservation planning under climate change, particularly when only sparse data are available. Socioeconomic information adds a new dimension to conservation planning, which is actually misleading and incomplete without it.

The microecosystems in the leaves of the pitcher plant, Sarracenia purpurea, were studied over a thirty day period. These plants were kept out of doors. One of these plants was later brought into the laboratory and four leaves were studied concurrently with four tubes. These studies were intended to show differences, if any, between leaves studied in the field and those in the laboratory, and between the leaves and an artificial environment. Organisms in all of these vessels were counted and their total biomass and oxygen consumption graphed. Three of the larger organisms found were typical of this species of pitcher plant, one through its entire life cycle and the other two for their larval stages. An interesting finding was that the alga, Microthamnion, seems to inhibit the growth of Tetrahymena, probably due to some extrametabolite. Paramecium was apparently excluded from all leaves in the field. The leaves of the pitcher plant were found to be ideal for the field and laboratory investigation of ecological forces due to their natural occurrance, small size, and rapid turnover of organisms. / Science, Faculty of / Zoology, Department of / Graduate

An ecological study of the important winter ranges of the Ashnola population of California bighorn sheep (Ovis canadensis californiana Douglas) was conducted from May 1963 through August 1964. Emphasis was placed upon the floristic composition, productivity, soils and the use by cattle, deer and bighorn of the ranges. The principal climax community between 3500 and 4500 feet is dominated by Agropyron spicatum and Koeleria cristata; above 4500 feet, often to 6200 feet, it is dominated by Agropyron spicatum and Festuca idahoensis. Both communities have developed on Rego Dark Gray soils. Overgrazing of the climax communities leads to serai communities dominated by Koeleria cristata and Poa secunda in the lower situation and Artemisia frigida and Koeleria cristata in the higher situation. Other serai communities which have arisen through overgrazing on Orthic Black soils are dominated by Poa pratensis, Poa secunda, or Bromus tectorum together with Stipa columbiana. The use by domestic cattle and, on some areas, the combined use by cattle and deer, are the principal factors presently maintaining the seral communities. Since bighorn use of the winter ranges occurs primarily after maturation of the forage, most areas heavily utilized by bighorn and not abused by cattle were found to be in the climax state. Bighorn were shown to have an affinity for the climax Agropyron - Koeleria and Agropyron - Festuca communities and utilized them three times more than seral communities. Chemical analysis revealed that by N. R. C. (1957 & 1963) feeding standards recommended for domestic sheep and cattle the seven forage species which compromised more than 95 percent of the bighorn winter diet contained sufficient crude protein, fat, fibre, ash, nitrogen free extract and calcium for maintenance. However, by the same standards, all species and notably the grasses, were deficient in phosphorus. Low phosphorus and moderate calcium levels produced unfavourable calcium:phosphorus ratios by mid-winter. Stipa columbiana, a principal increaser species and an unimportant item in the bighorn winter diet, was inferior to the other species investigated. Agropyron spicatum, a decreaser species and the most important bighorn food species, appeared to be the most nutritious grass. The retrogression of Agropyron spicatum dominated climax communities caused by past overgrazing by domestic stock, present forage competition with domestic stock, and possible phosphorus deficiencies are believed to be the principal factors presently limiting the bighorn population. / Land and Food Systems, Faculty of / Graduate