APPLICATION OF C₂ 3A CHAMBERS : GROWTH AND ALLOMETRY

A continuous and precise measurement of growth rate, expressed in carbon biomass, was allowed from experiments in Closed Chambers Automated in Artificial Atmosphere (C₂ 3A System). Curves were generally better fitted by a function power like w =a (t-t_o)^b, with b close to 3. Such a function is represented by a straight line in log-log scales, suggesting relationship with allometry properties.
A model of carbon investment is proposed, leading to explicit the formula:

w=a (t-t_o)^b = n ^-n NARⁿ k (t – t_o)ⁿ

with NAR=Net Assimilation Rate.
Allometry properties are represented by S=k ^n-1, the relation between the area S and , the capacity of storage of carbon assimilated by unit of S; =SLA LWR, with SLA=Specific Leaf Area and LWR=Leaf Weight Ratio.
The role of NAR is discussed, the formula suggesting the effect provoked by a difference of NAR (for instance between sun and shade plants) on growth curves.
Properties of such a formula are discussed and illustrated from experiments on wheat.
The systematic decrease of the relative growth rate, as l/t, imposed by the relationship of allometry does not fit with the concept of exponential growth.
The use of RGR, as a criterion of treatment effects on plant growth, are re-examined from the example of treatments giving a growth stimulation without any change of RGR.

International Symposium on Plant Production in Closed Ecosystems

M. André

CO₂ balance, growth curves, relative growth rate, Triticum aestivum, wheat

https://doi.org/10.17660/ActaHortic.1996.440.1