Browsing by Subject "Proteaceae"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Restricted
    A small-scale RNA isolation protocol useful for high-throughput extractions from recalcitrant plants
    (2010) Smart, Mariette; Roden, Laura Catherine
    Many plants indigenous to South Africa are rich in secondary and oxidizing compounds such as pigments, complex polysaccharides and polyphenols. This makes isolation of high quality RNA for analysis of gene expression difficult. Here we describe a cost-effective isolation protocol suitable for RNA extraction from recalcitrant plant species. This method uses small amounts of tissue, so is useful when material is limited, and is easy to process large numbers of samples at once. We have used the method successfully with mature leaves of Protea hybrid ‘Sylvia’, and species P. repens, Leucospermum hybrid ‘Succession’, resurrection plants Xerophyta humilis and Craterostigma pumilum, and mature needles of Pine (Pinus radiata). RNA was analyzed spectrophotometrically and was found to be of high purity with low levels of contaminating compounds. Electrophoretic analyses on denaturing formaldehyde agarose gels and an Agilent 2100 Bioanalyzer confirmed the presence of RNA of high integrity. This is the first description of plant RNA integrity number (RIN) values for these plants using the algorithm designed for analyses of plant RNA containing multiple ribosomal bands. The RNA could successfully be used for reverse transcription and gene amplification.
  • Thumbnail Image
    Item
    Open Access
    The ecology of invasions by Pinus (pinaceae) and Hakea (proteaceae) species, with special emphasis on patterns, processes and consequences of invasion in mountain fynbos of the southwestern Cape Province, South Africa
    (1989) Richardson, David Mark; Cowling, Richard M
    The fire-prone mountain fynbos of the southwestern Cape Province of South Africa has been severely invaded by introduced trees and shrubs. These invasions have transformed fynbos shrublands to dense thickets of trees and shrubs in many parts of the region, thus disrupting various natural ecosystem processes. The ecology of invasions by species of Pinus and Hakea (the most successful genera) was studied using a series of natural experiments in conjunction with autecological studies. The study was divided into main four parts: (i) case studies to elucidate major patterns and processes of invasion; (ii) studies of the life history and population ecology of selected invaders; (iii) studies of the determinants of invasibility; and (iv) assessments of the consequences of invasion and of control programmes. Bibliography: pages 235-272.
  • Thumbnail Image
    Item
    Restricted
    How do fires kill plants? The hydraulic death hypothesis and Cape Proteaceae "fire-resisters"
    (Elsevier, 2011) Midgley, J J; Kruger, L M; Skelton, R
    The actual mechanism which causes plant death after having been burned has been poorly studied. One possibility is that fire causes direct, or indirect, fatal damage to plant hydraulic systems. If true, this suggests that burned plants ultimately die of drought. This hypothesis was tested on the post-fire response of a "fire-resister" species of the Cape Proteaceae, as well as by analysing its morphology. Fire-resisters are plants which are incapable of resprouting, but nevertheless survive some fires. Mortality of the studied fire-resister appears to be compatible with a hydraulic death hypothesis because i) most post-fire mortality occurred within days, ii) it occurred from the base-upwards and iii) correlated negatively with stem diameter rather than plant height. Higher levels of survival of the fire-resister is probably due to absolutely thicker bark than co-occurring re-seeder species of the same age. Since this bark has not evolved to protect buds, it has probably evolved to protect stem hydraulic systems.