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Title: Studies on transport phenomena in stolons of Saxifraga sarmentosa, with particular reference to the action of auxin
Author: da Cruz, Gil Silva
ISNI:       0000 0001 3401 4740
Awarding Body: University of London
Current Institution: Royal Holloway, University of London
Date of Award: 1976
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The problem of hormone-directed transport has been the subject of a considerable amount of work yet its mechanism still remains unclear. Two main hypothesis have so far been proposed to explain this phenomenons: i-The hormone, in particular auxin, acts directly on the whole pathway of transport probably by stimulating protoplasmic streaming in the transcellular strands (Davies and Wareing, 1965). Alternatively, the hormone may directly promote the photosynthetic activity in the leaves (Bidwell, 1973; Bidwell and Quong, 1975) or directly interfere with the mechanism of phloem "unloading" at the "sink" region (Phillips, 1975). The second hypothesis advocates an indirect effect of the hormone on the long-distance transport of metabolites. According to this theory, the hormone stimulates or maintains the rate of synthetic activity at the treated region, therefore creating a "metabolic sink" towards which the nutrients and/or plant growth regulators are attracted. This hypothesis stems from the "nutrient diversion theory" put forward by Went (1936; 1939) who, in connection with the problem of apical dominance, suggested that the nutrients moved within the plant towards areas of highest auxin concentration. Objections have been raised against both theories, and up to now, there is no direct and definitive proof which might enable us to accept one or reject the other. In the present study, an attempt was made to verify the validity of either of these two theories in stolons of Saxifraqa sarmentosa by using the following approaches: 1. Blockage of the downward stream of auxin by using several inhibitors of auxin polar transport, and observing their effect on the auxin-directed translocation of metabolites and their metabolism. 2. Reduction of the demand for assimilates at the treated region by either inhibiting the synthesis of RNA and/or proteins, or supplying directly to that area metabolites or high concentrations of mannitol. Other points were also investigated, namely the effect of several substances on the movement and metabolism of IAA-5-3H, as well as an attempt to localize the pathway of the basipetal transport of applied auxin.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Botany