ETHYLENE BIOSYNTHESIS, CARBOHYDRATE METABOLISM AND PHENYLALANINE AMMONIALYASE ACTIVITY IN GRAVIREACTING KNIPHOFIA FLOWER STALKS.

Ernst J. Woltering, D. Somhorst, J. Beekhuizen, W. T.J. Spekking
Gravistimulation of cut flowering stems of Kniphofia (hybrid) causes rapid upward bending due to a decreased growth rate at the upper half and an increased growth rate at the lower half of the flower stalk. ACC synthase activity and ethylene production increased in the lower half of the gravistimulated stem, whereas no changes were observed in upper halves and vertical stems. EFE activity, PAL activity, carbon dioxide production and the contents of starch and soluble sugars were similar in upper and lower halves.

Treatment of the stems with ethylene or inhibitors of ethylene synthesis and of ethylene action inhibited elongation growth in vertical controls but had no appreciable effect on the response to gravity.

The results indicate that changes in ethylene production or carbohydrate metabolism play no role in flower stalk gravitropism.

Woltering, Ernst J., Somhorst, D., Beekhuizen, J. and Spekking, W. T.J. (1991). ETHYLENE BIOSYNTHESIS, CARBOHYDRATE METABOLISM AND PHENYLALANINE AMMONIALYASE ACTIVITY IN GRAVIREACTING KNIPHOFIA FLOWER STALKS.. Acta Hortic. 298, 99-110
DOI: 10.17660/ActaHortic.1991.298.10
https://doi.org/10.17660/ActaHortic.1991.298.10

Acta Horticulturae