Articles by Author: Will Cresswell

Search results for Will Cresswell

We found 27 results for you
  1. Somatic Embryogenesis in <em>Eucalyptus grandis</em>

    Item type: Journal Article • Journal: South African Forestry Journal
    Culture conditions for the in vitro propagation of Eucalyptus grandis via somatic embryogenesis were investigated. Induction and maturation of somatic embryos, production of plantlets and hardening-off procedures are detailed.
  2. The effect of micronutrients and gibberellic acid on the germination and metabolism of seedlings of <em>themeda triandra</em> forsk

    The effect of micronutrients and gibberellic acid on the germination and metabolism of seedlings of <em>themeda triandra</em> forsk

    Dormancy of the caryopsis of Themeda triandra Forsk was shown to be broken by the addition oí boron to the germination media. This effect was specific to boron, as no response was observed with zinc, copper, manganese, iron, cobalt and...
  3. The influence of nitrate and ammonia nitrogen on the photosynthetic and photorespiratory activity of selected highveld grasses exhibiting c‐4 photosynthesis

    The influence of nitrate and ammonia nitrogen on the photosynthetic and photorespiratory activity of selected highveld grasses exhibiting c‐4 photosynthesis

    A study has been made on the influence of nitrate and ammonia nitrogen on the carbon dioxide compensation point (T), carboxylating enzymes and growth of highveld grasses found at the primary, secondary and climax successional stages. The results obtained are...
  4. A study of the fine structure, enzyme activities and pattern of <sup>14</sup>co<sub>2</sub> incorporation of highveld grasses from different successional stages

    A study of the fine structure, enzyme activities and pattern of <sup>14</sup>co<sub>2</sub> incorporation of highveld grasses from different successional stages

    A detailed study of selected grasses has been made with respect to fine structure characteristics, enzyme activities associated with C‐4 and C‐3 pathway of photosynthesis, and short term 14CO2 incorporation experiments. A good correlation was obtained between the fine structure,...
  5. Variability in leaf surface features and water efficiency utilisation in C<sub>3</sub> and C<sub>4</sub> forms of <em>alloteropsis semialata</em> (R. Br.) hitchc.

    Variability in leaf surface features and water efficiency utilisation in C<sub>3</sub> and C<sub>4</sub> forms of <em>alloteropsis semialata</em> (R. Br.) hitchc.

    Alloteropsis semialata (R. Br.) Hitchc. occupies a unique position both taxonomically and physiologically in the Gramineae in that C3 and C4 photosynthetic and anatomical forms exist within a single taxonomic species. Both forms have been collected from a single ecological...
  6. A stimulation of an alternative photorespiratory CO<sub>2</sub> pathway by nitrogen in <em>themeda triandra ‐</em> a possible explanation for its sensitivity to nitrogen

    A stimulation of an alternative photorespiratory CO<sub>2</sub> pathway by nitrogen in <em>themeda triandra ‐</em> a possible explanation for its sensitivity to nitrogen

    Vacuum infiltration of inorganic nitrogen ions affected the photosynthetic rate and CO2 compensation point of Themeda triandra and Zea mays in a similar way. However these two plants differed markedly in their photorespiratory mechanisms in response to inorganic nitrogen. Increased...
  7. The regulation of starch accumulation in <em>panicum maximum</em> Jacq. by nitrogen

    The regulation of starch accumulation in <em>panicum maximum</em> Jacq. by nitrogen

    Electron microscopic studies of Panicum maximum (PCK C4 photosynthetic type) when grown under controlled growth conditions at low nutrient nitrogen (20 ppm N, KNO3) showed interesting second order bundle sheath cell organization: the cells were several times bigger than the...
  8. An ontogenetic study with special reference to leaf development in C<sub>3</sub> and C<sub>4</sub> forms of <em>alloteropsis semialata</em>

    An ontogenetic study with special reference to leaf development in C<sub>3</sub> and C<sub>4</sub> forms of <em>alloteropsis semialata</em>

    This ontogenetic study conducted at light and electron microscope level, describes several aspects of leaf development in C3 and C4 forms of Alloteropsis semialata. Emphasis is placed on the distribution and anatomy of vascular bundles as seen in transverse sections...
  9. The effect of night temperature and leaf inorganic nitrogen status on the C<sub>4</sub> Pathway enzymes in selected C<sub>4</sub> photosynthetic grasses

    The effect of night temperature and leaf inorganic nitrogen status on the C<sub>4</sub> Pathway enzymes in selected C<sub>4</sub> photosynthetic grasses

    Themeda triandra, Hyparrhenia hirta and Zea mays have a single bundle sheath with agranal, centrifugal chloroplasts suggesting a NADP‐ME‐type photosynthetic pathway. Plants grown in liquid cultures had a higher NADP malic enzyme activity than those grown in sand with nutrients...
  10. Growth analysis and photosynthetic rates in three selected grass species in the <em>burkea‐eragrostis</em> savanna

    Growth analysis and photosynthetic rates in three selected grass species in the <em>burkea‐eragrostis</em> savanna

    Three major grass species of the Nylsvley study site were studied: Eragrostis pallens. Digitaria eriantha and Panicum maximum. Growth analysis for the peak growth season was carried out with respect to phytomass, biomass and necromass.