Effect of K and N concentrations in nutrient solution on growth and quality of tomato transplants

Document Type : Full Paper


University College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran


The aim of this study was to evaluate the effect of different potassium (K) and nitrogen (N) concentrations in nutrient solution and their interaction on growth and quality of tomato transplants. A full factorial experimental design was carried out with three potassium concentrations (1.5, 3 and 6 meql-1) and three nitrogen concentrations (1.5, 3 and 6 meql-1) for 27 days after seed germination. Fresh and dry weight of stem, root and leaf, stem diameter, and leaf area were measured at the beginning and at the end of treating period. Biomass partitioning and growth characteristics were calculated. Increasing of K concentration was accompanied with increased stem diameter and dry weight, while nitrogen increment led to increase of stem diameter and fresh weight. Both N and K increased fresh and dry weight and area of leaves. While K increment expanded specific leaf area (SLA), N didn’t have any effect on SLA. Root mass fraction (RMF) and root: shoot ratio (RSR) decreased by increasing K and N concentrations. K didn’t affect leaf mass fraction (LMF), but nitrogen significantly increased LMF. While maximum stem mass fraction (SMF) was achieved in 6:1.5 (K:N) ratio, 1.5:6 ratio led to minimum SMF. Increasing of K concentration in nutrient solution significantly increased relative growth rate (RGR) and leaf area ratio (LAR), while didn’t affect net assimilation rate (NAR). Nitrogen also enhanced plant RGR, but its effects on NAR and LAR wasn’t significant. Interaction effect of potassium and nitrogen on biomass allocation and growth characteristics wasn’t significant. It can be concluded that higher K:N ratios could improve transplant quality.