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dc.contributor.advisorBerner, J.M.
dc.contributor.advisorVan Heerden, P.D.R.
dc.contributor.advisorEksteen, A.
dc.contributor.authorMalan, Charné
dc.date.accessioned2017-09-12T13:20:30Z
dc.date.available2017-09-12T13:20:30Z
dc.date.issued2017
dc.identifier.urihttp://hdl.handle.net/10394/25545
dc.descriptionMSc (Botany), North-West University, Potchefstroom Campus, 2017en_US
dc.description.abstractElevated CO2 levels could possibly increase the water use efficiency of important agricultural crops. The world´s most productive crops are C4 plants, for example, maize, sugarcane, sorghum and amaranth. C4 plants are generally less affected by elevated CO2 conditions than C3 plants due to the differing internal CO2 concentrating mechanism. It’s been theorized that C4 species evolved in an environment with a high CO2 concentration. This would increase the water use efficiency of the plants when compared to C3 plants. Various authors suggested that an elevated CO2 environment reduces the stomatal conductance of plants thereby delaying the effect of water deficit. This will in turn stimulate the biomass yield via stress avoidance. The objective of this study was to determine the direct effects of elevated CO2 on the physiology, growth, sugar production and yield of two sugarcane varieties. Speedlings of varieties NCo376 and N31 were grown in open-top chambers. The CO2 levels were controlled at 400 ppm (ambient) and 750 ppm (elevated) in 12 open-top chambers for a period of seven months. Soil water deficit conditions were avoided through irrigating frequently. The effects of CO2 treatment on photosynthesis, stomatal conductance, chlorophyll a fluorescence, biomass and stalk sucrose content was determined. Different varietal responses were observed during the trial. A reduction of 40% for N31 and 30% for NCo376 in stomatal conductance was observed. In spite of this, the increased CO2 conditions did not have an effect on the sugar production, cane quality, green leaf area and dry biomass. The elevated CO2 treated plants also had a higher fluorescence intensity than the control plants during the vegetative growth stages, therefore indicating that the sugarcane was responsive to the elevated (750 ppm) CO2 during this period. However, no effect on the rate of photosynthesis could be demonstrated. Overall it can be concluded that elevated CO2 conditions in the absence of soil water deficit lowered the stomatal conductance in sugarcane, but no changes, positive or negative were observed in the biomass and sugar yielden_US
dc.language.isoenen_US
dc.publisherNorth-West University (South Africa)en_US
dc.subjectBiomass yielden_US
dc.subjectChlorophyll a fluorescenceen_US
dc.subjectElevated CO2en_US
dc.subjectPhotosynthetic efficiencyen_US
dc.subjectPlant growthen_US
dc.subjectStomatal conductanceen_US
dc.subjectSugarcaneen_US
dc.titleInfluence of elevated CO2 on the growth, yield and photosynthesis of sugarcaneen_US
dc.typeThesisen_US
dc.description.thesistypeMastersen_US
dc.contributor.researchID11289937 - Van Heerden, Philippus Daniel Riekert (Supervisor)
dc.contributor.researchID21203083 - Berner, Jacques Maynard (Supervisor)


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