Agriculture Reference
In-Depth Information
Chapter 4
Theories of Leaf Longevity
Leaf scars of
Alnus japonica
Costs and Benefits of the Evergreen Versus Deciduous Habit
The approach to theoretical work on leaf longevity is inspired by optimization
models that came into vogue during the late 1960s to try to understand alternative
modes of adaptation (Lewontin 1978). Reasoning in this conceptual framework
and reviewing available data, Chabot and Hicks (1982) argued that leaves with
higher construction cost should be longer lived because the period of photosyn-
thetic gains to pay back the construction cost will be longer than for a leaf con-
structed at less cost. Using seven Mexican shrubs in the genus
Piper
(Piperaceae),
Williams et al. (1989) set out to test this idea that leaf longevity should be deter-
mined by the time required for a leaf to pay back the costs of its construction. They
found that, in contrast to Chabot and Hick's supposition, leaf construction cost
