Abstract
The axial growth of plant organs changes under genetic and environmental influences, which can be observed as alternations in cell proliferation and volume growth. For understanding growth controls of plant axial organs, we have studied root growth of Arabidopsis by kinematic analysis, which measures cell flux to calculate local rates of cell proliferation and volume growth at various positions. The kinematic data have been further analyzed by a newly developed mathematical model. The model assumes that the biological activity of a given organ is proportional to the cell number of the organ and is allocated into three aspects; cell proliferation, volume growth, and organ maintenance. The model-assisted analysis estimates efficiencies for these three aspects. We have applied this analysis to assess ploidy and temperature effects on the root growth. The analysis suggests that tetraploids are more efficient than diploids in volume growth and organ maintenance but less efficient in cell proliferation, and that the efficiencies of cell proliferation and volume growth decrease at low temperature. Based on the results, we will discuss availability and weakness of the current model.
