Relationship between frequency of adventitious shoot formation form main vein tissue at the connection part with leaflet in each leaf node of tomato and photosynthate accumulation in main vein tissue

The aim of this study was to obtain basic information about the frequency of adventitious shoot generation on main vein tissue at the leaflet connection part in tomato (Solanum lycopercicum L. cv ‘Momotaro’) and their generating loci. Tomato plants were cultivated hydroponically and all lateral buds were removed at the start of their elongation, in the same way as conventional cultivation, and all clusters were also removed at the anthesis of their first flower. The frequency of adventitious shoot formation on main vein tissue at the leaflet connection part in each leaf node, and furthermore, the sugar and starch contents in main vein tissue of the leaves in odd-numbers and Brix in those in even-numbers were investigated. Most adventitious shoots were generated from the main vein tissue at the connection part including a large and decompound leaflet. The leaves at higher nodes up to the 10sup(th) leaf had a higher frequency of adventitious shoots, whereas those above the 11sup(th) leaf were not significant. Additionally, the frequency of adventitious shoots from the main vein tissue at the connection part, a pair of large and decompound leaflets closest to the stem, was lower. Starch content in main vein tissue of the leaves in odd-numbers showed a similar trend line as the frequency of adventitious shoot formation. A significantly positive correlation was noted between the starch contents of the leaves in odd-numbers less than 0.6 mg starch・/gFW and the frequency of adventitious shoots generated from the main vein tissue at the connection part of large and decompound leaflets. These results suggest that the frequency of adventitious shoots generated from main vein tissue at the connection part of large and decompound leaflets of tomato was affected by the accumulation of starch, especially at a concentration of 0-0.6 mg starch・/gFW in the main vein tissue. Moreover, the frequency of adventitious shoot formation at the connection part with especially large and decompound leaflets was different with variable distances from the stem.