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Title: Physiological studies on the growth and development of the carrot, Daucus carota L.
Author: Olymbios, Christos Michael
ISNI:       0000 0001 3458 8269
Awarding Body: Imperial College London (University of London)
Current Institution: Imperial College London
Date of Award: 1973
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This thesis is concerned with a study of the external, environmental conditions on the growth and development of the carrot Daucus carota L., as well as the carotene content, morphogenetic and other effects of defoliation or extirpation of the apex. Auxanometer records of root growth in different environments were also obtained. Experiments have also been carried out to simulate environmental and other effects by means of external application of known plant growth substances, in an attempt to explain morphogenetic changes in terms of internal plant regulation. Briefly, the results of daylength/temperature experiments on tops and roots have indicated that maximum total plant growth results at relatively warm temperatures, but under these conditions the leaf fraction is favoured; lone-day treatment results in similar effects. Root and top temperatures had striking differential effects. Both can be simulated by gibberellic acid application which is not dependent on the site of treatment. At lower temperatures and in short—day, root growth is favoured, although total plant size may be less. Treatment with the dwarfing compound CCC which is known to have anti—gibberellic properties modified growth in a similar way to low temperature, a foliar spray being more beneficial for root growth. In contrast to gibberellic acid, application of cytokinin increases the growth (probably cell division as well as cell expansion) at or near the site of application which may be young leaves, hypocotyl or root. Only if cytokinins have direct access to the open vascular system is the effect noticeably away from the site of application. Root aeration is of vital importance to the carrot plant and lack of oxygen in the root medium affects both root and top growth detrimentally, although some degree of adaptation seems possible. Soil compaction greatly affects yield and maybe related to root aeration. High carotene content is promoted by relatively low temperature (15°0 and well aerated root media. The inter-relation of environmental effects in terms of internal carbohydrate and hormone balances have been discussed. Some conclusions are also drawn as to the practical application of some of these results.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available