The 2012 ASHS Annual Conference

In our previous report (Kakita et. al. Supplement to HortScience 46(9): S327, 2011), we found that the root permeability was changed when Japanese cultivar 'Reiyo' (R) was grafted on 'Receive' (r), but not Dutch cultivar 'Dundee' was grafted on 'Maxifort' (m). In this study, we investigate the physiological differences when plants were grafted on different Dutch and Japanese tomato cultivars. We used Dutch tomato 'Starbuck' (S) and (R) as scions, and (m) and (r) as rootstocks. Grafted plants were obtained each combination (i.e. S/m, R/r, S/r and R/m) and grew hydroponically until flowers on first-truss bloomed. We measured the fresh weight of the aerial parts, the surface area of roots, the root permeability and the water potential of exudates. The fresh weight of the aerial parts and the surface area of roots for S/m were the highest among 4 combinations. The root permeability and the water potential of exudates had no significant difference. We found that root growth was influenced by a scion, but the root permeability was not. These results indicate that the root permeability of rootstock was not influenced by scion, but the root area was. Because the total amount of absorbed solute might be different, the fresh weight of the aerial parts was different at S/m and the other grafted plants.