The Geography of Phytochemical Races

72 2 Examples Within Continents
Fig. 2.44 Map of Cinchona
sites in South America
showing the three taxa
involved in the complex
2.6.4 Lycopersicon pennellii (Solanaceae)
Lycopersicon pennellii (Correll) D’Arcy occurs in arid valleys in coastal Peru. Two
varieties exist, var. pennellii ranging from ca. 5°S to ca. 16°10′S, and var. puberulum
(Correll) D’Arcy, which inhabits a small area centered at ca. 14°30′S in the
vicinity of Ica (Fig. 2.45). The typical variety is characterized by the production
of an exudate rich in acylated sugar derivatives based upon glucose and sucrose
and a variety of aliphatic acids (Shapiro et al., 1994). The powerful antiherbivore
properties of these compounds are of particular interest to plant breeders and others
interested in improving commercial tomatoes. (See, for example, Rodriguez et al.,
1993, on the action of acylsugars on green peach aphids.) The two varieties differ
signifi cantly in their capacity to manufacture these compounds, var. puberulum producing
only a small fraction of the quantity and variety of structures found on var.
pennellii (Shapiro et al., 1994).
Chemical variety in the acylsugars known from the family is based upon the
capacity of glucose to accommodate up to fi ve acylating acids, while sucrose can
accommodate up to six. Detailed chemical information on these compounds from
various members of the family can be found in papers by King et al. (1988, 1990) and
Matsuzaki et al. (1989). In the case of compounds from L. pennellii, the acylating acids