Phosphorous uptake rate in two low phosphorous updated species, Aspalathus linearis and Podalyria calyptrata

Bachelor Thesis


Permanent link to this Item
Journal Title
Link to Journal
Journal ISSN
Volume Title

University of Cape Town

Due to the low P nature of soils within the fynbos biome of the Cape Floristic Region, plants have developed numerous mechanisms which enable them to better acquire phosphorous. A number of species have been reported to have specialised root morphologies (root clusters, mycorrhizae) that enhance P uptake. Plants may also down-regulate the uptake of P by decreasing the expression of genes that encode P transporters. Two Fabaceae species, Podalyria calyptrata and Aspa/athus linearis, were grown in hydroponics for 5 months at a low P supply of 4μM and P-depletion studies were conducted thereafter at 5 levels of external P (4, 10, 20, 50 and lOOμM). Growth rates (biomass accumulation) were also calculated as were root to shoot ratios for both species. A. linearis had a higher uptake rate than P. calyptrata. While the fresh biomass growth rate was similar in both species, P. calyptrata had a higher dry weight root to shoot ratio than A. linearis. The results showed that both species exhibited a lack of response to increasing P concentrations and had similar RGRs. Their uptake rates differed significantly (p<0.05) and this was likely due to their different root:shoot ratios. This indicates that both species would effectively grow in low P soils and in the case of P. calyptrata, in high P soils as well.