Costs of reproduction in circumpolar <Emphasis Type="Italic">Parnassia palustris</Emphasis> L. in light of global warming |
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Authors: | Sylvi M Sandvik Wenche Eide |
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Institution: | (1) Botany Department, University of Cape Town, Private bag, Rondebosch 7701, Cape Town, South Africa;(2) School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, Crawley, WA, 6009, Australia |
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Abstract: | In frequently burnt savannas, saplings face the formidable challenge of both recovering from, and eventually growing tall
enough to escape from, frequent fire damage. The aim of this study was to explore how saplings allocate carbon to achieve
these ends through carbon partitioning, storage and remobilization. Lignotuber total non-structural carbohydrate (TNC) concentrations
and δ13C values of Acacia karroo (Fabaceae; Mimosoideae) were determined in plants from two different juvenile stages. These were one year after a fire when
the plant consisted of numerous leafy shoots or coppices (“coppicing” stage), and three years after a fire when the plant
consisted of one pole-like stem (“Gulliver” stage). Gulliver lignotubers were found to have significantly larger TNC pools
(150 g vs. 97 g) and larger TNC concentrations (33% vs. 24%, w/w) than coppice lignotubers showing that post-coppice Gullivers
recharged TNC in the lignotuber. δ13C values from the stems of plants in the Gulliver stage were significantly enriched (>1‰) in 13C compared to both coppicing (P < 0.01) and adult (P < 0.05) plants. Changes in both the amount of stored carbon and in the δ13C values indicated dependence on stored carbon reserves, and partially heterotrophic growth for initial resprouting. The plants
appeared to use both current photosynthate and stored carbon reserves for growth of the Gulliver stem. The use of stored carbon
is hypothesized to promote fast stem growth rates to a height where saplings escape fire injury. |
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Keywords: | Acacia karroo Resprouting Total nonstructural carbohydrates Stable carbon isotope δ 13C Heterotrophic Fire ecology Savanna |
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