Net fluxes of mineral nutrients, water, and carbohydrate influenced by manganese in root and shoot ofCucumis sativusL.1

Abstract

Abstract An experiment was conducted with cucumber (Cueumis sativus L., cv. Sumter) plants in the vegetative phase of growth to determine effects of manganese deficiency (0.2 μM Mn) and toxicity (182 μM Mn) on fluxes of several mineral nutrients, water, and carbohydrate in the root and shoot, beginning 43 d after germination. Plants were sampled every three days from 34 to 58 d after germination. First and second derivatives of regression equations were used to estimate fluxes and study source/sink phenomena of dry weight (DW), fresh weight (FW), H2O, Cu, Fe, Mn, Zn, N, P, and K in root and shoot tissues. With Mn sufficiency (1.8 μM Mn), both root and shoot acted as sinks for of each of the 10 dependent variables through 58 d. In contrast, Mn deficiency caused net loss of K and N from the root beginning at 53 and 56 d, respectively, and net loss of P and Fe from the shoot beginning at 57 and 58 d, respectively. With Mn toxicity, net loss of Cu, N, and K from the root began at 46, 46, and 51 d, respectivel...