PARENT SESSION
Contributed Oral Session 63: Plant Genetics: Population Level Implications
Tuesday, August 9, 1:30 PM - 5:00 PM, Meeting Room 519 A, Level 5, Palais des congrès de Montréal
Variation in growth, form, and life history in dwarf and normal pitch pines in the Long Island Pine Barrens.
Fang, Wei1, Fox, Gordon*,2, Taub, Daniel3, Gurevitch, Jessica 4, 1 Long Island University - Brooklyn Campus, Brooklyn, NY, USA2 University of South Florida, Tamp, FL, USA3 Southwestern University, Georgetown, TX, USA4 State University of New York, Stony Brook, Stony Brook, NY, USA
ABSTRACT- All plant species vary in size and growth rate, and many vary in form. Genes, environment, and their interaction can all be causes; untangling these is important for our understanding of plant ecology and evolution as well as for conservation. We examined variation in growth, size, and form in a unique dwarf population of pitch pine (Pinus rigida), on Long Island, NY, and in surrounding populations of normal-statured pitch pines. There is an abrupt shift in these traits over a distance of ca. 1 km in the Long Island pine barrens. Normal-statured plants reach a height of 8-12m, while dwarf pines are only 1-3m. Our earlier work showed that in natural populations dwarf pines grew more slowly, survived more poorly, and reached maturity sooner than normal-statured pines. We conducted two reciprocal transplant experiments between several populations of each kind, using maternal sibships of wild-collected seeds. We recorded twice-annually the survival, height, number of stems per plant, and cone production of several thousand individuals. We analyzed contributions of "source type" (dwarf vs. normal), population within source type, family within population, growth location type (dwarf vs. normal), and location within growth location type, as well as all interactions, for traits related to growth, form, survival, and maturation. Growth location is by far the largest factor affecting growth rates, form, and survival. The influence of factors that may reflect genetic variation was statistically significant for some growth-related traits in one experiment, but was always much smaller than the effect of location. However, source type and population within source type are important factors for maturation rates. Broad-sense heritabilities appear to be much larger for maturation rate than for growth, form, and survival characters. Conservation interest has focused on the form of dwarf pines; our results suggest their life history characters may be more distinctive.
Key words: survival, reciprocal transplant, Life histories, growth