Esterase Activity in Developing Pods of Soyheans

Four stages of soybean pod development of four varieties of Glycine max were surveyed for esterase enzymes by starch-gel electrophoresis. Differences in esterase banding patterns occur among the four varieties investigated. Enzyme changes accompanying pod development were observed. Pod collection procedure affected the number of esterase bands visible, with collection in dry ice giving more visible bands than did collection in regular ice. The separation of enzymes by zone electrophoresis, using a solid supporting medium (Smithies, 1955) in combination with histochemical staining techniques (Hunter and Market, 1957), yields a reproducible pattern ( zymogram) of sites of enzyme activity. Enzymes, thus identified electrophoretically, are useful for studying genetic variation within a plant species (West and Garber, 1967; Meisinger, 1967; Scandalios, 1969). Enzyme changes accompanying development have been previously observed (Schwartz, 1962; Steward, Lyndon, and Barber, 1965; Meisinger, 1967", Snyder and Kleese, 1968; Scandalios, 1969) . The purpose of this study is to investigate genetic v.;iriation of specific esterases as well as changes in the enzymes accompanying developing pods in four varieties of Glycine max. MATERIALS AND METHODS Seeds from four varieties of Glycine max, Ford, Hark, Kazai, and Kimusume, were electrophoretically analyzed for sites of esterase activity by starch-gel electrophoresis. To study the changes in esterase activity during the development of the soybean pod, plantings were made on four different dates in 1968-May 11, May 26, June 15, June 22; these will be referred to as dates l, 2, 3, and 4, respectively. Comparisons between pods could be made by collecting pods at the same node position on the plants on Aug. 27. Two collecting procedures were used. At the time of collection in the field, some pods were collected and stored in regular ice and, others, in dry ice. Crude extracts were made by crushing one seed on a 5-mm square of Whatman no. 1 filter paper. Five squares of filter paper saturated with extracts from different seeds were inserted into a horizontal slot made in the center of a starch gel. In this way, valid *RSF is a NSF URP participant 1 Journal Paper No . .J-6577 of the Iowa Agriculture and Home Economics Experiment Station. Ames, Iowa. Project No. 1335. 3 Meisinger, .J. 1967. Esterases in developing soybean pods. Unpublished ~SF URP Report·1967.