Responses of fruit quality, leaf protective enzyme systems of tomato to soil water and fertilization

To explore the optimum soil water content and fertilizer amount during the fruiting stage of tomato, three soil water treatments (W1, 90%-100%; W2, 70%-80% and W3, 50%-60% of field capacity) and three fertilizer levels (F1, N0.187 g/kg+P2O5 0.131 g/kg; F2, N 0.267 g/kg+P2O5 0.187g/kg; F3, N 0.347 g/kg + P2O5 0.243 g/kg) were set to study fruit quality, leaf protective enzyme system and chlorophyll content of potted tomato at the stage. The results show that in the whole fruiting stages, the fruit quality is improved under the W1F2 treatment, and the penetrant (as free amino acid) level in fruits and activities of leaf protecting enzymes are high under the W2F2 treatment, while the MDA content is low. Chlorophyll content of leaves is high under the W2F3, and tomato fruit yield per plant is higher under the W2F2. Correlation analysis indicates there are positive correlations between fruit quality and SOD activity and chlorophyll content at the fruiting stages, while there is a negative correlation between fruit quality and MDA content. There are significant positive correlations between free amino acid contents and SOD activity and Pro content, while there is a significant negative correlation of between free amino acid and MDA content. In general, combining N 0.267 g/kg, P2O5 0.187 g/kg and 70%-80% soil relative water content is the optimum condition for tomato development during the fruiting stage.