Correlation, between {beta}-galactosidase and auxin-induced elongation growth in etiolated pea stems

ß-Galactosidase, -galactosidase, ß-glucosidaseand ß-xylosidase were studied in relation to auxin-inducedelongation of etiolated pea stems. Frozen-thawed sections wereincubated in substrate solutions and individual enzyme activitywas determined. Results were as follows:

1. Only ß-galactosidase activity was remarkably enhancedby 2,4-D in the concentration range which induced remarkableelongation.
2. Auxin-induced increase in ß-galactosidaseactivityreached maximum after 1 hr treatment of the sectionwith 2,4-D(10^–5 M), and was nearly constant afterwards.
3. Auxin-enhanced ß-galactosidase activity was observedeven if auxin-induced apparent elongation was osmotically suppressedby mannitol.
4. Correlation analysis indicated that ß-galactosidaseactivity had a high positive correlation with auxin-inducedelongation and increase in lateral face area of the section,while none of the other enzyme activities did.
5. Measurementof in vivo distribution of four glycosidase activitiesin intactthird internode of the epicotyl made clear that onlyß-galactosidaseshowed maximum activity in the zonewhere endogenous elongationwas maximum.

(Received February 5, 1976; )