Abstract
The objective of this research was to investigate the internal water movement in tomato and the fruit development under greenhouse culture. Water movement through the main stem of tomato was emerged from daytime until midnight. Cultivation of tomato without top pruning results in plant height becoming very tall and producing a lot of flower buds. Therefore, moisture absorbed by the roots after sunset was used to recover the moisture deficit of plant occurred in daytime and develop the fruits. The water flow at petiole and peduncle indicated symmetrical direction because of the connection of these conductive tissues. During the days with plenty of solar radiation caused abounding transpiration from leaves by high temperature and big saturation deficit such that the water stored in the fruits outflow. From the evening until the next morning, the amount of moisture exceed the outflow rate during daytime was replenished through peduncle as the stem flow, which becomes a maximum around eight o'clock in the night. These were confirmed by the change of fruit's size, which had a little positive correlation with the flow through peduncle while had little correlation with meteorological elements. Irrigation of evening is expected to increase the inflow to fruit by translocation and active water absorption rapidly.
