An automatic image analyzing system for evaluation of elongating behavior of plant hairy roots exposed to herbicidal...

The elongating behavior of pak-bung hairy roots was evaluated by automatic tracing of the root tip point employing computer-aided image analysis. Though the root elongation rate in the absence of herbicides was approximately constant, the addition of 1.0 pmol/dm3 2,4-dichlorophenoxyacetic acid (2,4-D) or pyributicarb to the culture led to gradual deterioration of the elongation rate during measurements over a 25 h period. The saturated value of the elongation rate (R(G)sat) was determined as a measure to predict herbicidal toxicity to the roots by formulating the time profiles of the elongation rate. Under the conditions of 0.2-1.0 pmol/dm3 2,4-D and 0.110 micromol/dm3 pyributicarb, the dose-response profiles based on the R(G)sat values overlapped closely with those based on the manually determined elongation rate in prolonged cultures for 168 h. It was concluded that the system developed could be a useful tool for the assessment of herbicidal toxicity in the hairy roots.