Potato root and leaf phosphatase activity in response to P deprivation

Background Plants are not able to take up organically bound phosphorus (P) before it is hydrolyzed by extracellular phosphatases while intracellular phosphatases play a role in P remobilization. Aims The aim of this study was to evaluate intra‐ and extracellular acid phosphatase activity as well as root and shoot growth of two modern starch potato cultivars at different levels of P deprivation. Methods In vitro propagated potato plantlets (cultivars Kuba and Cardoso) were grown in sand and fertigated with five different P concentrations, ranging from 1 to 0.05 mM P. Growth parameters, plant P concentrations, and acid phosphatase activities were determined after 40 days. Results Shoot and root biomass decreased gradually with decreasing P supply, while the root‐to‐shoot ratio increased. Shoot P concentration decreased steadily, but root P concentration remained constant at P levels below 0.5 mM. Root‐associated and root intracellular acid phosphatase activity increased in both cultivars with rising levels of P deprivation. The activity of acid phosphatases in old but not in young leaves was increased with P deprivation. Intracellular acid phosphatase activity was genotype dependent, with higher activity in the cultivar Kuba than in Cardoso. Conclusions Our results point to a tissue specific regulation of acid phosphatase activity depending on plant P status and potato genotype. Increasing root‐associated acid phosphatase activities may help P starved potato plants to ensure a sufficient P nutrition. Further research is needed to unravel the roles of leaf intracellular acid phosphatases in potato.