Response of self-thinning to artificially reduced levels of leaf areain monocultures of Trifolium pratense
Document Type
Article
Journal/Book Title/Conference
Annals of Botany
Volume
55
Publication Date
1-1-1985
First Page
361
Last Page
366
Abstract
Greenhouse grown monocultures of Trifolium pratense L, were partially defoliated to test the hypothesis that the constant of proportionality (K) in the self-thinning rule is a function of leaf area. This constant equates mean weight (w) and density (p) in self-thinning populations by the equation
w=K·ρ−1.5 (1)
Pruning leaflets did not affect the pattern or occurrence of density-related mortality but, as predicted, did affect K, which was reduced by 25 per cent as leaf area was decreased from an average of 7.3 to 3.9 m2m−2. For both self-thinning and non-self-thinning populations, leaf area was substituted for K in eqn (1) to give
wαLA.ρ−1.5 (2)
Multiple linear regression showed that this expression was significant for all three defoliation treatments. Regressions with tree data grouped by genera were also significant and indicate that eqn (2) may be a more general expression of the relation between mean weight and density in even-aged monocultures. The self-thinning rule may be a special case of eqn (2) which expresses itself when leaf area attains some upper limit.
Recommended Citation
Dean, T.J. and J.N. Long. 1985. Response of self-thinning to artificially reduced levels of leaf area in monocultures of Trifolium pratense. Annals of Botany 55:361-366.