Seedling architecture and life history evolution in pines

Abstract

Much of the work on life history evolution in plants has dealt with allocation of reproductive effort (Abrahamson 1975; Abrahamson and Gadgil 1973; Gaines et al. 1974; McNaughton 1975; Oka 1976; Stearns 1976, 1977, 1980; Newell and Tramer 1978; Primack 1979). The juvenile period, however, occupies a major and critical portion of the life cycle of many species. Allocation of growth among vegetative organs during the juvenile period may place constraints on later development. The work of Marks (1975) and others (Troughton 1960; Monk 1966; Harper 1977; Pitelka 1977; Abrahamson 1979) suggested that species with short life spans make a greater investment in shoot biomass than do long-lived species. Preferential investment in shoot biomass is thought to permit a faster rate of development, but to sacrifice the capacity to withstand competition. We explored relationships between division of biomass and other aspects of life history: pines investing heavily in foliage as a proportion of total biomass had characteristics associated with r-selection, including small size at maturity, small seeds, low tolerance of competition, early reproduction, and short life spans. Species with the opposite constellation of characteristics invest more heavily in structural and conductive organs, roots, and stems. These character associations suggest that allocation of biomass in the juvenile stage is a fundamental aspect of life history diversification in plants.

Citation

Strauss, Steven H.; Ledig, F. Thomas. 1985. Seedling architecture and life history evolution in pines. The American Naturalist, Vol. 12(5): 702-715