DIRECT ANALYSIS OF ROOT ZONE DATA IN A MICROCULTURE SYSTEM

The feasibility of using a whole plant microculture system coupled with image analysis to observe and quantify elusive root growth phenomena was demonstrated. Subtle differences in root initiation and growth rate for maple microcuttings inserted into three distinct rooting media were recurrently registered over the span of the rooting phase in terms of root length, number, and weighted density (equivalent to fresh weight) without disturbing the rooting environment. This method provided a non-intrusive time-course assay for take-all disease symptom expression on wheat lines (degree and rate of root lesion development), which paralleled the relative resistance rated in field plots. Although agar-solidified media had a relatively high light transmission (nearly 84% through 6.6 cm medium depth), roots could only be clearly perceived through a thickness of about 2 cm, and were often completely obscured when embedded to a depth greater than 5 cm. However, there was no detectable loss of definition for roots observed through Gelrite-solidified media (non-diffuse light transmission of 97%) up to a depth of 6.6 cm. © 1990 Kluwer Academic Publishers.