Effect of Gibberellic Acid on Growth, Gibberellin Content, and Chlorophyll Content of Leaves of Potato (Solanum tuberosum)

Spraying potato plants with a solution of gibberellic acid (GA)when the 15th leaf was emerging increased the area of this leafand its total gibberellin content, assayed by dwarf French beanleaf disks. GA, assayed by lettuce hypocotyls, was not detectedin leaves from untreated plants. The GA content of leaves fromGA-treated plants decreased after 2 weeks and none was detectableafter 5 weeks; apparently it was converted to another gibberellin,possibly the same as the natural gibberellin. GA increased chlorophyllcontent per leaf but increased leaf area more so that the chlorophyllper unit area decreased, and the leaves were paler than untreatedleaves.