Changes in homogalacturonans and enzymes degrading them during cotton cotyledon expansion

When infiltrated with 8-aminonaphthalene-1,3,6-trisulphonate-labeled hexamer of galacturonic acid (GalA6-ANTS), cotton cotyledons degrade it. Endo-polygalacturonase levels are high during the period of rapid expansion and then fall, while the opposite is true of exo-polygalacturonase.