Automated Quantification of Roots Using a Simple Image Analyzer

Abstract

AbstractManual methods for estimating root lengths in washed samples are time consuming, tedious, and subjective. The objective of this research was to evaluate the use of an inexpensive commercial image analysis system for measuring the length of roots in samples washed from soil. The analyzer consists of a high‐resolution television camera and a comparator, which measures the intersections of the TV scan lines and roots in the view area. Mathematical corrections are derived for overlapping roots in the sample and for limitations in system resolution. Errors due to nonrandom orientation of roots were minimized by scanning in two directions. Methods for contrast and light control are discussed. On a 1000 cm simulated root sample, the uncorrected length measurement was < 50% of the actual length. Correcting for overlaps increased the measured length to around 70% of actual length. Overlap and resolution correction resulted in errors less than 5%. Coefficients of variation (CV) for repeated measurements on a single, undisturbed wheat (Triticum aestivum L.) root sample were around 0.5%, while errors resulting from nonrandom dispersion of samples in the tray were 2‐3%. The image analysis system therefore appears to capable of providing reliable root measurements.