Phosphorus supply influences the molybdenum, nitrate and nitrate reductase activity in eggplant

SummaryGreenhouse experiments were conducted for two years (1993-1994) with eggplants being supplied H3PO4 as the P source (1 mM, 2 mM and 4 mM) to study its influence on Mo distribution and on aspects of nitrate metabolism and fruit quality. The NO3– and Mo in leaf blades, petioles and fruits as well as foliar in vivo nitrate reductase (NR; E.C. 1.6.6.1) activity were analysed. P application at levels exceeding 1 mM P altered the NO3– and Mo status and distribution in the above-ground organs of eggplant. The 4 mM P treatment induced the highest NO3– accumulation in leaf blades and lowered transport to the fruits. Moreover, lower P (1 and 2 mM) supplies led to increased NO3– concentration in fruits. The 4 mM P treatment induced a greater Mo concentration in the fruit, whereas the soluble form of Mo was nearly equally distributed between the shoot organs.