Abstract:In order to elucidate the heterosis on nitrogen uptake in the F1 hybrids, the nitrogen (N) absorption characteristics of the eggplant genotypes with different N efficiencies and their hybrid F1s were studied. Under normal and low N stress conditions, root volume, root dry weight, N uptake, root activity, nitrate reductase activity and glutamine synthetase activity of leaves were studied in three typical eggplant genotypes with different N efficiencies and their hybrids. Compared with low N efficiency genotypes（L），the root volume, root dry weight, root activity, total N uptake per plant, nitrate reductase activity and glutamine synthetase activity of the cultivars with high N efficiency (H1 and H2) are all higher. In the three F1 hybrids, F1-1 (L × H1), F1-2 (L × H2), and F1-3 (H1 × H2), the root volume, root dry weight , root activity, nitrate reductase activityof leaves, glutamine synthetase activity of leaves and total N uptake per plant of Hm and Hp are mostly positive，in which the hybrid F1-3 has the best heterosis. Using the heterosis on N uptake in the F1 hybrids, it will be useful to improve the N metabolism and increase the N efficiency of the plant.