Invariant Scaling Relationships for Interspecific Plant Biomass Production Rates and Body Size

The allometric relationships for plant annualized biomass production ("growth") rates, different measures of body size (dry weight and length), and photosynthetic biomass (or pigment concentration) per plant (or cell) are reported for multicellular and unicellular plants representing three algal phyla; aquatic ferns; aquatic and terrestrial herbaceous dicots; and arborescent monocots, dicots, and conifers. Annualized rates of growth G scale as the 3/4-power of body mass M over 20 orders of magnitude of M (i.e., G proportional to M(3/4)); plant body length L (i.e., cell length or plant height) scales, on average, as the 1/4-power of M over 22 orders of magnitude of M (i.e., L proportional to M(1/4)); and photosynthetic biomass M(p) scales as the 3/4-power of nonphotosynthetic biomass M(n) (i.e., M(p)proportional to M(n)3/4). Because these scaling relationships are indifferent to phylogenetic affiliation and habitat, they have far-reaching ecological and evolutionary implications (e.g., net primary productivity is predicted to be largely insensitive to community species composition or geological age).