Differential Tolerance of Tomato Strains to Maintained and Deficient Levels of Phosphorus

Abstract

Abstract Seven strains of tomato ( Lycopersicon esculentum Mill.), with similar growth rates under adequate P availability, differed in dry matter accumulation by up to 73% when grown under P deficiency in a sand-alumina medium. The rate of P uptake per unit of root weight or length was a primary factor in strain capacity to acquire P under low-P stress. Variation in efficiency of internal P use also contributed to differential tolerance to P deficiency. The factors indicated to be responsible for tolerance to P-deficiency stress were present to different degrees in the different strains. Uptake rates per unit root were equally well correlated with total P absorption whether based on root length or root weight, suggesting that it may be most practical to screen for superior uptake capacities on the basis of root weight.