S06 - Session P10 - Session - Water transports and plant developments in tomato with adventitious roots

Authors: Toshihiro Umebayashi *, Yasuhiro Suzuki, Hiroomi Kanda, Hiroyuki Imanishi, Naoko Kitamoto, Yasunori Yoshida

In plants, water ascends through xylem conduits from roots to top (leaves and fruits). Although adventitious roots from the stem are also formed in many plants, the relationship between the water-conducting systems of adventitious roots and the plant developments remains poorly understood. Tomato ( Solanum lycopersicum ) is one of the species whose adventitious roots are well formed. Physiological studies about water transport with adventitious roots may contribute to the improvement of cultivation techniques in tomato. In this study, we conducted a hydroponics experiment to clarify physiological characteristics on water conduction and plant developments in tomato with adventitious roots. Adventitious roots were formed at the distance of ca. 40 cm above the ground, and the new roots were observed within one week after starting to moisten the stem. Water absorbed from adventitious roots was similar volume to that of underground roots. In control plants, hydraulic conductance of the stem near the ground was lower than that at the distance of ca. 40 cm above the ground. On the other hand, in plants that adventitious roots were formed, hydraulic conductance was similar between the stem formed adventitious roots and the stem near the ground, and increased above the place where the adventitious roots were formed (ca. 60 cm above the ground). In addition, plants with adventitious roots showed increases of total water absorption, plant height, and total fruit weight. Thus, many adventitious roots formed on the stem may improve water and mineral deficiencies. Our results showed the adventitious roots works to actively support developments of the plant.