No description available.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Date palms (Phoenix dactylifera L.) and papayas (carica papaya L.) are two commercially important plantation crops. Their economic potential in South Africa and worldwide is increasing. However, due to disease, pests and socio-economic reasons, planting material is in short supply. Micropropagation provides a method for rapidly propagating selected superior cultivars for commercial and environmental interests. A satisfactory process for the regeneration of elite cultivars should result in individuals phenotypically and genetically identical to the explant from which they were derived. However, due to somaclonal variation generated during in vitro culture, the true-to-typeness is questionable. For this reason a southern African survey for off-types on date palms produced using somatic embryogenesis was conducted. Plant growth variations such as leaf variegation, seedless fruit, broad leaves, compact growth habit and parthenocarpic fruit were recorded and possible explanations for each phenomenon given. Factors influencing the date palm initiation process such as decontaminating agents, plant growth regulators, explant type and nurse cultures were investigated. A double decontamination process with 2.6% and 1.3% sodium hypochlorite was most effective at reducing contamination. Alternative plant growth regulators, TIBA and NAA were ineffective as a substitute to 2,4-D for somatic embryogenesis. The size of the explant and "nurse cultures" played an important role in explant growth and initiating callogenesis. A "nurse culture" reduced the time in culture significantly. The problem areas in the three commercial tissue culture techniques used for date palms were outlined. In the second part of the study, factors influencing initiation, multiplication and rooting of papaya were determined. Presoaking with antibiotic, Rifampicin, and various fungicides had a positive effect on decontaminating papaya explants, while Bronocide™ had little effect. Various methods and materials were used to optimize papaya multiplication and rooting in vitro. The growth and multiplication of papaya was optimal at 50 g l ¯¹ sucrose. Gelling agent, Gelrite, increased multiplication rates significantly but had a negative effect on overall growth causing plants to become vitrified. The addition of activated charcoal reduced vitrification but also reduced multiplication rate. Activated charcoal greatly improved overall growth of papaya and reduced leaf senescence. No vitrification was observed in multiplying papaya cultures where agar and Gelrite combinations were used, but multiplication rate was reduced compared to cultures grown on Gelrite alone. callus removal from the bases of papaya at subculturing reduced multiplication rate and influenced elongation, growth and leaf senescence. Lower concentrations magar and Gelrite improved rooting percentages, but did not provide good support. Damaged roots and lower rooting percentages were observed on plantlets treated with IBA for four weeks compared to those exposed for only two days. A one hour pulse with a higher concentration (5 mg l ¯¹) of IBA greatly improved rooting percentage and further eliminated a second subculture onto an IBA-free medium after two days. Good, strong roots with root hairs were produced on vermiculite medium containing equal volumes of DS salts and vitamins. Modified lids with cotton-wool plugs also reduced leaf abscission. In vitro grafting using stericrepe proved impractical, while grafting in vitro unrooted papaya plants onto ex vitro seedlings was more successful, using wedge and slant grafts. Grafts sealed with pegs and Parafilm™ were less effective. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2000.

Constitution d’un corpus rassemblant les dates des événements à caractère officiel relevées dans la documentation égyptienne, entre l’Ancien Empire et la fin du Nouvel Empire (env. 3000 – 1100 av. J.-Chr.) ; les seules dates retenues dans le corpus sont les dates complètes, qui notent, en plus de l’année, la saison, le mois et le jour, selon l’usage des anciens Égyptiens. À partir de cette base de données, plusieurs thèmes ont été abordés en analyse : calendrier et système de datation ; les dates d’avènements, de couronnement, de décès et d’enterrement des rois ; les dates de séjour du roi à Thèbes au Nouvel Empire ; les dates d’expéditions aux mines et aux carrières ; les dates artificielles ; enfin, les dates manifestant une concordance avec un événement notable connu par ailleurs (d’ordre historique, astronomique ou religieux). Le but de la recherche entreprise était d’une part de mettre en exergue, au sein de la base de données constituée, les événements officiels susceptibles d’avoir été entrepris à dessein à une date spécifique, d’autre part de tenter de comprendre les raisons de ces choix calendériques. Un calendrier général regroupant les données du corpus ainsi que les dates des célébrations religieuses et des diverses fêtes, est donnée (sous forme de tableau synoptique) en annexe. / Constitution of a corpus bringing together the dates of the official events found in the egyptian documentation, from the Old Kingdom to the end of the New Kingdom (ca. 3000-1100 BC). The only dates kept in the corpus are the complete ones, which give season, month and day in addition to year, according to ancient egyptian use. From this database, several themes were addressed in the analysis: calendar and dating system; dates of accession, coronation, death and burial of kings; dates of king’s stay in Thebes during the New Kingdom; dates of quarries and mines expeditions; artificial dates; and dates showing a significant correlation with a significant event known elsewhere (historical, astronomical or religious). The aim of this research was firstly to highlight, within the database, the official events that may have been deliberately started by a specific date, secondly to try to understand the reasons for these calendrical choices. A general time frame containing the data of the corpus and the dates of various religious celebrations and festivals, is given (in the form of summary table) attached.

No description available.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

No description available.

No description available.