A Study Of Scaling Law On Respiration Rate, Biomass, Nitrogen And Phosphorus Content Of Plant Seedlings

Studies on scaling law among plant different attributes are large, involving abundant species, but most of those ignore influence of seasonal change on plant physiology attributes. From December of 2012 year, we sampled from field once a quarter. We take five kinds of plant seedlings, Pinus massoniana, Cunninghamia lanceolata, Machilus pauhoi, Phoebe bournei and Schima superba, as research objects and explore scaling relationships among seedling respiration rate, biomass and nitrogen (N) and phosphorus (P) content so as to reveal scaling relationship on plant structure, function and physiology attributes more specificly and clearly. Main results are following.Seedling size had influence on allometric relationship between seedling respiration rate and total biomass. Allometric exponents of conifer trees and broadleaf trees fitted by seedling respiration rate versus total biomass and leaf biomass varied from seasons. However, the allometric exponents of confiner trees were smaller than those of broadleaf trees.Allometric exponents of conifer trees and broadleaf trees fitted by seedling respiration rate versus whole N and P content had differences in seasons. The allometric exponents of confiner trees were smaller than those of broadleaf trees. In function and community level, the allometric exponents fitted by seedling respiration rate versus whole N and P content were both greater than unity.Eight groups of scaling relationships, seedling root biomass versus root N and P content, seedling stem biomass versus stem N and P content, leaf biomass versus leaf N and P content, seedling total biomass versus whole N and P content, varied in different seasons in intraspecific level. Besides, the eight groups of scaling relationships varied with species.In intraspecific and function level, scaling exponents were smaller than or equal to unity, but in community level, the scaling exponent was smaller than unity.Scaling relationships between N and P content in root, stem, leaf and whole seedling varied from species and seasons. Scaling constants of conifer trees between N and P content in every organ were smaller than ones of broadleaf trees. In community level, the scaling exponent between N and P content in every organ was nearly isometric.The nine groups of biomass allocation scaling relationships, leaf versus stem biomass, root versus leaf biomass, stem versus leaf biomass, aboveground versus belowground biomass, stem versus aboveground biomass, leaf versus aboveground biomass, root versus total biomass, stem versus total biomass, leaf versus total biomass, varied from species. Scaling exponents of root versus stem biomass, aboveground versus belowground biomass, root versus total biomass, stem versus total biomass of conifer trees were statistically indistinguishable from ones broadleaf trees. Scaling exponents of root versus leaf biomass, stem versus leaf biomass, stem versus aboveground biomass of conifer trees were smaller than ones of broadleaf trees. Scaling exponents of leaf versus aboveground biomass, leaf versus total biomass of conifer trees were smaller than ones of broadleaf trees. In community level, scaling exponents of root versus stem biomass, aboveground versus belowground biomass, leaf versus aboveground biomass, leaf versus total biomass were smaller than unity significantly. Scaling exponents of root versus leaf biomass, stem versus leaf biomass, stem versus aboveground biomass, root versus total biomass, stem versus total biomass were greater than unity significantly.To sum up, some allometric relationships among plant respiration rate, biomass and N and P content varied with season or phenophase. Besides, species and size can influence on allometric relationships.