Department of Plant Sciences

Phosphorus (P) is not only a constituent of key cell molecules such as ATP, nucleic acids, and phospholipids, but it is also a pivotal metabolic regulator of many processes including energy transfer, protein activation/inactivation, signal transduction cascades, biosynthesis of macromolecules, photosynthesis, respiration and carbon allocation. Plants are notoriously P-starved due to its extremely low soil bioavailability. To thrive under P-deprivation, plants elicit an elegant myriad of rescue strategies to enhance P-solublization and acquisition from bound P-forms. To evaluate relative growth responses, P-solublization, acquisition and utilization efficiency, diverse Brassica cultivars were grown with sparingly soluble P-sources [Rock-P (RP) and Ca3(PO4)2 (TCP)] or with low/high P-supply in solution and soil culture experiments, respectively. Tested cultivars showed considerable genetic diversity in biomass accumulation, concentration and contents of P and Ca, P-stress factor (PSF) and P-efficiency characteristics. Using a soil low in P (Mehlich-III-extractable-P) with (+P) or without P (0P), cultivars showed genetic diversity in P-utilization efficiency (PUE), P-efficiency (PE), P-efficiency ratio (PER) and PSF. Cultivars producing higher root biomass accumulated higher total P-contents, which in turn was related negatively to PSF and positively to shoot and total biomass. Cultivars depicting high PUE and PE, and low PSF values were better adaptable to P-stress environments.