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

摘要

Greenhouse experiments were conducted for two years (1993-1994) with eggplants being supplied H_3PO_4 as the P source (l mM, 2 mM and 4 mM) to study its influence on Mo distribution and on aspects of nitrate metabolism and fruit quality. The NO_3~- 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 NO_3~- and Mo status and distribution in the above-ground organs of eggplant. The 4 mM P treatment induced the highest NO_3~- accumulation in leaf blades and lowered transport to the fruits. Moreover, lower P (1 and 2 mM) supplies led to increased NO_3~- 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.