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dc.contributor.advisorWray, John L.en
dc.contributor.authorGilkes, Amanda Francesen
dc.coverage.spatial224pen
dc.date.accessioned2021-04-08T08:57:13Z
dc.date.available2021-04-08T08:57:13Z
dc.date.issued1995
dc.identifier.urihttps://hdl.handle.net/10023/21854
dc.description.abstractThe sulphate assimilation pathway was investigated in barley (Hordeum vulgare). The enzymes ATP sulphurylase, thiosulphate reductase, sulphite reductase, serine acetyltransferase and cysteine synthase proposed as steps in the pathway of higher plants, have been detected in barley seedling leaves. Cysteine synthase was purified ca 400 fold from extract of 7 day old barley seedling leaves to give an activity of 52 μmols cysteine produced/min/mg protein. Differential centrifugation of mechanically ruptured protoplasts showed cysteine synthase was likely to be predominantly or exclusively located within the chloroplast. Specific staining for cysteine synthase activity of non-denaturing polyacrylamide gels suggest the presence of a single form of the enzyme in barley. Development of cysteine synthase activity in barley seedlings was shown not to be dependent on light but was influenced by nutritional status. Selenate, which was shown to be toxic to barley seedlings, was used as the positive selection agent in a screen designed to isolate whole plant mutants defective in sulphate assimilation. Over 70,000 M₂ seedlings (mutagenised in the Mi with 2mM sodium azide) were screened for resistance to selenate. Nine M₂ seedlings were selected as most likely to be defective in sulphate assimilation. M₃ progeny were obtained from four of the M₂ selections. The M₃ progeny showed no resistance to selenate and specific activity staining of non-denaturing polyacrylamide gels showed the presence of functional ATP sulphurylase, thiosulphate reductase, sulphite reductase and cysteine synthase. These results suggest it is unlikely that these M₂ selections carry a heritable mutation in sulphate assimilation.en
dc.language.isoenen
dc.publisherUniversity of St Andrewsen
dc.subject.lccQK753.S8G5
dc.subject.lcshPlants—Effect of sulfur onen
dc.subject.lcshBarley—Geneticsen
dc.titleThe biochemical genetics of sulphate assimilation in barley (Hordeum vulgare)en
dc.typeThesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnameMSc Master of Scienceen
dc.publisher.institutionThe University of St Andrewsen


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