Quantitative analysis of 3-dimensional root architecture based on image reconstruction and its application to research on phosphorus uptake in soybean

Abstract

Quantification of 3-dimensional (3-D) plant root architecture is one of the most important approaches to investigating plant root growth and its function in nutrient acquisition and utilization. However, no effective methods have been reported hitherto to quantify 3-D root architecture parameters, making it difficult to further study the 3-D characteristics of the root system and its function. In the present study, we created a rapid algorithm to reconstruct 3-D root system images based on the basic structural features of such linear objects as roots, using 2-D root images taken by digital CCD cameras at multi-viewing angles. This method is very effective in the reconstruction of plant root system images, thus enabling us to obtain the digital model of 3-D root architecture and its 3-D skeleton, based on which some major root architecture parameters can be calculated. Using this method, we were able to acquire 3-D parameters of soybean root architecture whose root diameter was more than 0.3 mm, including tap root length, total root length, average basal root angle, ratio of root width to root depth, percentage distribution of root length in different layers and root distribution in different 3-D regions of the growth medium. We also quantitatively analyzed the relationship between different root architecture parameters and such plant nutrition parameters as soybean biomass and phosphorus (P) uptake. Our study may provide a new tool in studying the growth and nutritional functions of plant root systems.