Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.652611
Title: Growth and photosynthesis in woody species of the Brazilian Cerrado, with particular reference to Kielmeyera coriacea mart. (Guttiferae)
Author: Houghton, Stefan K.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1993
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Abstract:
Woody species of the Brazilian Cerrado show morphological and functional adaptations to the soil water, soil nutrient and fire stresses of the Cerrado environment. This thesis considers these adaptations in relation to the growth and photosynthesis of Cerrado woody species, and in particular Kielmeyera coriacea Mart. (Guttiferae). Growth of K. coriacea and other Cerrado woody seedlings under field conditions is slow, but within the range seen for other late successional woody species. K. coriacea displays a limited growth rate plasticity in response to favourable conditions, with a maximum potential specific growth rate of 0.054 d-1. K. coriacea has relatively high unit leaf rates, but low leaf area ratios, due to an inherent low specific leaf area (SLA). Low SLA values are compounded by a rapid ontogenic decline in leaf weight ratio (LWR). Declining LWR is due to high biomass partitioning to root development. Within the root and shoot, partitioning is biphasic, with an initial 'establishment' phase of leaf and lateral root favoured development, and a secondary phase dominated by main root, i.e. xylopodium, development. The cotyledons have a maximum net photosynthetic rate of 11.0 μmol m-2 s-1 under favourable conditions, and provide the majority of photosynthate for the 'establisment' phase. Leaf emergence is episodic, or flushing, and individual leaf areas vary depending on their position within the flush. Leaf primordium production parallels leaf emergence, and maintains 4 unemerged primordia at the shoot apex. Adaptations, such as leaf scleromorphy and xylopodium formation, severely limit the growth potential of Cerrado woody species. Low growth rates under field conditions are primarily due to lower unit leaf rates (E), and are associated with slow leaf-area development.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.652611  DOI: Not available
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