Browsing by Author "Van der Willigen, Clare"

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    Aspects of the physiology of the resurrection plant Xerophyta Humilis under different environmental conditions
    (2002) Loffell, D. A.; Farrant, Jill M; Van der Willigen, Clare
    Xerophyta humilis is a resurrection monocot that is able to survive drying of its tissues to an air-dry state. in order to assess the alidity of laboratory-based experimentation, and the results obtained from such studies, a comparison of aspects of X. humilis physiology under different environmental conditions was undertaken. Analyses of chlorophyll fluorescence, gas exchange parameters, pigment concentrations and electrolyte leakage were performed on plants dehydrated under laboratory conditions differing with respect to light intensity ("high light" (ca. 1400 ųmol.m-². s-¹) and "low light" (ca. 400 ųmol. m-². s-¹)). Physiological parameters were also examined during rehydration under high and low light laboratory conditions, and natural field conditions. Plants maintained fully hydrated for some time were also examined under laboratory conditions for the occurrence of rhythmic patterns in their daily physiology, and for any evidence of acclimatisation to the different environments.
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    Comparisons of the resurrection grass, Eragrostis nindensis, with the related desiccation-sensitive species, E. curvula
    (2001) Van der Willigen, Clare
    Desiccation tolerance of the inner leaves of Eragrostis nindensis is compared with the desiccation sensitivity of the outer leaves, as well as those of the closely related species, E. curvula. Both E. nindensis and E. curvula dehydrate to a relative water content (RWC) ofless than 5% in two weeks. Photosynthetic activity in E. curvula is maintained down to 40% RWC, after which further drying results in a sudden irreversible breakdown of the photosynthetic system and its pigments.