Comparison of Leaf Development in Normal (+/+), Entire (e/e), and Lanceolate (La/+) Plants of Tomato, Lycopersicon esculentum 'Ailsa Craig'

Abstract

Developmental processes that result in the morphological and histological differences between the compound leaves of normal (+/+) Lycopersicon esculentum `Ailsa Craig' and those of the mutants "entire" (e/e) and "lanceolate" (La/+) are described. Despite considerable differences in mature leaf size and form, the dimensions of the shoot apical meristem, arrangement of young leaves in the bud, and pattern of leaf expansion are similar in the three genotypes during the developmental stages examined. In (+/+) leaves, lateral leaflet formation begins earlier and lasts longer than in (e/e) and (La/+), resulting in more pairs of leaflets. In the (e/e) genotype, growth in the lamina of the terminal leaflet is initiated earlier, and expansion proceeds relatively faster than in (+/+) leaves. In (La/+) leaves, lateral leaflets are usually absent, and while the lamina is initiated at the same stage as in (e/e) leaves, extension occurs more slowly than in either of the other two genotypes, resulting in a narrow leaf blade. In comparison with (+/+) and (e/e), cell enlargement in the adaxial protoderm becomes detectable earlier and proceeds at a greater rate in (La/+) leaves, resulting in greater cell area in mature leaves.