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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Die invloed van kroonblare, steellengte en loofblare op aspekte van die na-oesfisiologie van Dianthus caryophyllus L.

Fourie, Marthinus 15 September 2014 (has links)
M.Sc. (Botany) / Please refer to full text to view abstract
2

The effect of water stress and pretreatment with sucrose on ethylene sensitivity of cut carnation flowers.

O'Reilly, Linda 08 August 2012 (has links)
M.Sc. / The commercial value of cut flowers, whether for ornamental use or as an export product, has increased significantly over the years. Much attention is given to flower quality and flower longevity. These two factors are influenced by preharvest and postharvest treatments. The major postharvest loss reduction techniques in carnation flowers include regulation of preharvest growing, use of improved harvesting techniques, use of various storage techniques, use of growth regulators and use of floral preservatives. Senescence of carnation flowers (Dianthus caryophyllus L. cv. White Candy), is accompanied by a climacteric rise in ethylene synthesis and an increased sensitivity of the flowers to ethylene. A pulse treatment with sucrose caused a delay and suppression of the climacteric rise in ethylene synthesis. The action of sucrose, with reference to ethylene, was similar to that of cytolcinins. Dry storage also caused an increase in flower longevity. This is due to the flower's ability to maintain water balance by lowering the cells osmotic potential. Dry storage is of importance, as transportation of the flowers occurs under these conditions. Although sucrose increased the longevity of freshly cut carnations, it caused a decrease in longevity of flowers that were subjected to water stress. With the lowering of the tissue water potential through treatment with sucrose and thereafter by dry storage, the flowers are subjected to stress, and are not able to recover even after rehydration. Applied sucrose increased the carbohydrate pool, thereby resulting in a gradual decline of starch. Administering both sucrose and water stress to the carnation flowers resulted in an early peak in the sugar content, as well as an early depletion of sugar in the flower petals. Cytokinin activity in untreated carnation flowers appeared to be higher compared to flowers treated with sucrose. Water stress have the effect of decreasing cytokinin levels and activity. It is thus clear from the results of this study, that carnations subjected to water stress through dry storage, should not be pretreated with any preservative containing sucrose, as it leads to a reduction in vase life.

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