Details zur Publikation

Kategorie Textpublikation
Referenztyp Zeitschriften
DOI 10.1127/0340-269X/2005/0035-0449
Titel (primär) Ephemeral pools as stressful and isolated habitats for the endemic aquatic resurrection plant Chamaegigas intrepidus
Autor Heilmeier, H.; Durka, W. ORCID logo ; Woitke, M.; Hartung, W.
Quelle Phytocoenologia
Erscheinungsjahr 2005
Department BZF
Band/Volume 35
Heft 2-3
Seite von 449
Seite bis 468
Sprache englisch
Abstract Ephemeral pools are widespread in (semi-)arid regions, where they form unique, mostly isolated habitats in an otherwise dry landscape matrix. They are characterized by extremely variable conditions, the most important stress factors being (1) frequent and fast desiccation and rehydration, (2) long dry seasons, (3) intensive solar irradiation and high temperatures during the dry season, (4) large diurnal oscillations of O2 and CO2 concentration and pH in the pool water, (5) extreme nutrient shortage, especially nitrogen. One functional plant type being highly adapted to these stressful conditions are aquatic resurrection plants, i.e. poikilohydric cormophytes like Chamaegigas intrepidus (Scrophulariaceae). This species grows endemically in ephemeral rock pools on granite outcrops in Central Namibia. Ch. intrepidus shows a number of anatomical, biochemical and physiological adaptations to the complex of extreme habitat conditions such as contractive xylem, velamen radicum, accumulation of abscisic acid, dehydrins and carbohydrates during desiccation. Nitrogen deficiency is partly avoided by acquisition of amino acids and an efficient utilisation of urea. Chamaegigas populations on single inselbergs are genetically very highly isolated, whereas gene flow between sub-populations from different pools on one inselberg is rather high. In accordance with the predominantly outcrossing breeding behaviour, most genetic diversity is found within a pool. A habitat model showed clear niche partitioning between Ch. intrepidus and the less desiccation-tolerant species Limosella grandiflora with respect to depth of the pools. The specific constitutive dehydration tolerance mechanisms displayed by Ch. intrepidus are discussed as a vital adaptation to the low predictability of the occurrence and duration of periods favourable for growth and reproduction
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Heilmeier, H., Durka, W., Woitke, M., Hartung, W. (2005):
Ephemeral pools as stressful and isolated habitats for the endemic aquatic resurrection plant Chamaegigas intrepidus
Phytocoenologia 35 (2-3), 449 - 468 10.1127/0340-269X/2005/0035-0449