Underground structures and mycorrhizal associations of Solanum centrale (the Australian bush tomato)
Underground structures and mycorrhizal associations of Solanum centrale (the Australian bush tomato) Thesis
Faculty of Agriculture, Food and Natural Resources
- Author(s): Dennett, A
- Published: 2008
- Publisher: University of Sydney
- Volume: Hons. BSc (Agriculture)
Abstract: Solanum centrale (Solanaceae) is an Australian indigenous food plant with potential uses as a desert crop species. This project investigated the little understood underground structures and mycorrhizal associations of S. centrale to assist the domestication process. Eight naturally colonised and cultivated sites in South and Central Australia were observed and samples of lateral and fine (secondary) roots were taken for anatomical study and to determine resprouting ability in the glasshouse. In addition, a glasshouse trial spanning 10 weeks was conducted to determine the response of S. centrale seedlings to mycorrhizal fungi and phosphorus nutrition at zero P, low P (0.15 g) or high P (0.3 g), applied as soluble phosphate. S. centrale was found to form clonal communities connected by underground lateral roots. Shoots were produced at irregular intervals on lateral roots and responded extremely rapidly and favourably to simulated disturbance in the glasshouse. Tap roots were occasionally found with a shoot and lateral roots often turned downwards to grow vertically. Fine roots were sparsely located on laterals and were old and brittle at the driest sites. Despite this, mycorrhizas were observed in the fine roots at all field sites. In the glasshouse experiment, the effect of mycorrhizal fungi on root colonisation and plant growth and development varied depending on phosphorus application. Mycorrhizal fungi colonised 48% of root length in inoculated zero P plants but only 2% of roots at low P and no roots at high P. Inoculation with mycorrhizal fungi had no effect on dry weight, root length and plant height of low or high P plants, but significantly increased growth at the zero P level (P<0.05). However inoculation increased the average root phosphorus content by 42%, decreased root to shoot ratio by 92% and decreased root biomass by 41% at all P levels, despite negligible colonisation at low or high P. This suggests that the presence of mycorrhizal fungi in the rhizosphere influences plant morphology. Furthermore, the absence of mycorrhizal associations under high P suggests that no benefit is conferred to the host in high nutrient environments. This may prevent an unnecessary drain of photosynthate from the plant when P is not limiting. The positive response of S. centrale to mycorrhizal inoculation, and its ability to rapidly resprout from roots, highlights its suitability to an arid environment. This work demonstrates the potential of S. centrale as a cultivated desert food plant.
- Urls: http://www.nintione.com.au/resource/Angela-Dennett-Hons-Thesis-Structure-Solanum-Centrale.pdf, https://web.archive.org/web/20200324003606/http://www.desertknowledgecrc.com.au/resource/Angela-Dennett-Hons-Thesis-Structure-Solanum-Centrale.pdf
- Publisher Location: Sydney
- Keywords: Aboriginal food, arid-zone flora, root-sprouting, vegetative reproduction, phosphorus response, plant hormones