Phyllotaxis on the Main Shoot of the Wild Tomato Plants Calculated by the Orthostichy System.

Abstract

The angle of divergence between each pair of neighboring leaves on wild tomato plants, Lycopersicon pimpinellifolium (Just.) Mill., was measured with a semicircular protractor with an accuracy of ± 2.5 degrees. Not only in individual plants but in different plants with 10 leaves, the angles between pairs of mature leaves that developed sequentially on the main shoot with left-handed phyllotaxis ranged widely, from a maximum of 154.7 degrees between the first leaf and the second leaf and a minimum of 119.3 degrees between the second and the third leaf. The angle between the each pair of neighboring leaves from the third and the tenth leaf was intermediate, ranging between 120.3 to 141.3 degrees. The mean angle of divergence on one plant was calculated to be 135.3 degrees. The same pattern was observed also in plants with right-handed phyllotaxis that developed 10 or 11 leaves on the main shoot.The angle of divergence between the terminal leaf and the first inflorescence was almost identical as that of pairs of leaves on the main shoot. The arrangement of nodes 7 to 12 of leaf primordia on the main shoot was similar. These results indicate that the phyllotaxis of tomato plants was 3/8, with an angle of divergence of 135 degrees, as calculated by the orthostichy system. Because the accuracy of measurement was within ± 2.5 degrees, our results would also be compatible with phyllotaxis of 5/13 (about 138.4 degrees), 8/21 (about 137.1 degrees), 13/34 (about 137.6 degrees), or the limiting value of the main series in Schimper-Braun's law, (3-√5) /2, (about 137.5 degrees).