Abstract
Changes in water relations, carbohydrate contents, and acid invertase activity in expanding gladiolus perianths on cut stems were studied.
1. The specific rate of elongation of the perianth was fastest just before anthesis, but slowed down while the floral organs unfolded; it approached zero as the perianth became fully expanded.
2. Pressure potential of tissue water was high while the perianth was growing rapidly.
3. Fructose and glucose were the predominant soluble sugars in the perianth. These solutes were considered to contribute to the low osmotic potential of perianth tissues during their elongation process.
4. Acid invertase activity of perianth tissue was correlated to the specific rate of elongation. There was no correlation between the enzyme activity and the growth rate when the perianth was wilting.
5. Starch in florets was considered to be the primary source of soluble carbohydrates which contribute to the early stages of flower expansion.
6. At the wilting stage, soluble sugars were probably translocated from the perianth to other organs.
