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>Magister Scientiae - MSc / Chromosome doubling has become an important tool in breeding programmes as it offers the ability of introducing novel traits into existing plants. Doubled haploid plants are highly valued by both consumers and breeders as these plants usually show larger flower, leaves and fruit, thus making them more marketable. Marianna open pollinated plum rootstocks’ adaptability to different soil types and moisture conditions has been favoured in polyploidy studies as parental material in breeding programmes. The potential of the microtubule depolymerizing herbicide (oryzalin) for in vitro chromosome doubling were investigated by optimizing the concentration and incubation time of plant shoots to the antimitotic agent. Meristem tissues were treated for two time intervals (24 and 48 h) with five different concentrations of oryzalin (50, 75, 100, 150 or 200 μM) in liquid Murashige and Skoog (MS) medium. After treatment, plants were allowed to grow under a 16/8 h light/dark photoperiod at 24±2˚C for 4 weeks. One and two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry (MS) was used to separate, visualise and identify differently expressed proteins. Furthermore, changes in ROS accumulation, photosynthetic pigmentation, lipid peroxidation and antioxidant enzyme activity (SOD, APX and GR) were investigated. Flow cytometry results revealed that treatment of plants with oryzalin concentrations ranging from 75 to 150 μM induced ploidy after 24 h exposure whereas, 200 μM produced mixoploids containing both tetraploid and octoploids plants after 24 h exposure. Longer incubations of 48 h were detrimental to plant tissues as complete mortality was observed in the higher concentration (100 to 200 μM) treatments. Mass spectrometry analysis identified 14 differentially expressed protein spots that were characterized into different functional categories. ROS accumulation, the extent of lipid peroxidation and antioxidant capacity were differentially regulated in response to oryzalin treatment whereas photosynthetic pigments were significantly enhanced. The results suggests that oryzalin-induced proteins may act as potential biomarkers to improve fruit characteristics in future breeding programs whereas antioxidant enzymes play an important role in scavenging ROS in plants to enhance their adaptability to different environmental conditions.

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All-American interrogates J. Hector St. John de Crevecoeur’s definition of “American" in the 1782 text, Letters from an American Farmer, which inspired the Eurocentric, sexist and heterosexist ideals girding the notion of what is now called the “American Dream." Mainstream media project narratives that suggest that the ideals in Crevecoeur’s epistles have been fully extended beyond his narrow scope in the Obama era. All-American, however, offers poetry that illuminates modern and contemporary instances in urban and rural settings of racism, colorism, gender bias, ability discrimination and homophobia thwarting this idealistic worldview. Its formal and free verse explores the journey of four generations of one family as members grapple with discrimination, disability and disease and interrogates the heteronormativity and racism that girds the faith to which they cling. Whereas many contemporary poets eschew the confessional in storytelling, All-American employs it unabashedly. Moreover, All-American is interested in language poetry, not only that which plays with various Englishes but also with the languages that color them, that percolate under the surface. It aims to make music of these dialogical languages, these inexorable narratives. It lets the dead and dying tell their stories, which are no less American, though they are unpopular in an America racing to rid itself of past shame. All-American faces the shameful things Americans can do to one another and celebrates humans’ innate will to thrive, love and die with dignity—with hopes of inspiring dialogue and healing that will make American ideals more accessible to those on the periphery. / Master of Fine Arts