Quantitative Estimation of Living Wheat‐Root Lengths in Soil Cores¹

Abstract

A rapid, efficient method for separating living wheat (Triticum aestivum L.) roots from dead roots in field soil samples is needed to understand the dynamic nature of wheat root development, because the proportion of living roots is highly variable and often may constitute less than 20% of the estimated length. A soil core, wrapped in a cloth “root bag” with a weave comparable to a 100‐mesh screen (0.149 mm opening) was suspended in a container of water from a wrist‐action shaker. Roots, organic residues, and sand remained in the bag, but fine sand, silt, and clay washed out. Roots and organic material were then decanted from the remaining sand. A 1% aqueous solution of congo red stained the living roots red; nonliving roots remained unstained or were stained a brownish pink. After flotation separation of the stained roots from debris, living root length was estimated. Newman's grid method was modified to measure root length with an accuracy of ±9% as determined with known lengths of string. With these combined techniques of separation, staining, and length measurement, we could determine rooting density with an accuracy of ±9%. When incubated at 15 C, severed living wheat roots could be stained for up to 1 week, but stainability dropped to less than 35% after 5 weeks. Most monocot roots stained more intensely than dicot roots, indicating that monocot‐dicot root separation from the same root medium may faciliate studies of root competition.

Rooting Characteristics of Corn, Soybeans and Barley as a Function of Available Water and Soil Physical Characteristics

“…All roots were identified by eye, hand picked from the soil, stained with Congo red (Ward et al 1978) and their length estimated using the grid technique tested by Tennant (1975 …”

Comparison of Vertical Distribution of Live And

“…Roots were separated into < 1 mm fine root diameter and separated into live and dead categories, according to their colour and mechanical consistency. The additional vital staining technique with Congo red was also used for this purpose (Ward et al 1987). …”

Original Article. Effects of loose kernel smut caused by Sporisorium cruentum onrhizomes of Sorghum halepense

“…At the end of the growing cycle of the weed, the aerial dry matter (ADM g.pl-1) and rhizome dry matter (RDM g.pot-1.) was determined according to Ward et al (1978). Data were analyzed and means were compared using the method of least signifi cant differences (LSD) (p <0.05%) using SAS 6.03 (SAS, 1989).…”