Published online by Cambridge University Press: 03 October 2008
A fluorescent-dye technique has been developed to measure root length of field crops. Roots are washed from soil samples, stained for about 30 min in a solution of fluorescein diacetate in acetone, washed, spread out on a tension table and photographed under UV light. Lengths of fluorescent roots recorded on the photograph are estimated by line intersection. The method is quick, simple, inexpensive and largely eliminates the usual time-consuming, tedious process of hand-sorting live roots from organic debris. Whereas all the roots of young laboratory-grown plants take up the dye, some older roots of field-grown crops do not fluoresce. Data indicate that the method may also give information on root diameter.