ISHS Acta Horticulturae 559: V International Symposium on Protected Cultivation in Mild Winter Climates: Current Trends for Suistainable Technologies
EFFECTS OF GROWTH REGULATORS ON ROOTING AND STEM ELONGATION IN PROPAGATION OF FIVE FLOWERING TROPICAL PERENNIALS |
| Author: | R. Schoellhorn |
| Keywords: | Stachytarpheta, Dichorisandra, Cestrum, daminozide, chlormequat chloride, paclobutrazol, uniconazole, Idole-butyric acid, Naphthalene acetic acid |
| Abstract:
In three separate experiments, tip or node cuttings of five tropical perennial species were studied for either their response to chemical growth regulators to control stem elongation during propagation or chemical rooting hormones. In the first experiment, unrooted cuttings of Stachytarpheta mutabilis (Jacq.) Vahl, S. mutabilis var. violacea Mold., and S. urticifolia Sims.) were dipped daminozide (2500 and 5000 mgL-1), daminozide and chlormequat chloride tank mix (2000 mg·L-1 each), paclobutrazol (2 and 4 mg·L-1), uniconazole (2 and 4 mg·L-1), or untreated control. The interaction of chemical and species was significant for stem elongation and total roots formed in propagation. Daminozide and the daminozide-chlormequat chloride mix gave the greatest control over stem elongation, with the greatest stem elongation occurring in Stachytarpheta mutabilis var. violacea. Root development was inhibited by daminozide treatments and stimulated by triazole chemicals, however, S. urticifolia showed enhanced root development with all treatments over untreated controls. In separate experiments cuttings of Dichorisandra thyrsiflora Mikel. and Cestrum elegans (Brongn) Schldl. were evaluated for root development using the following chemical treatments: a commercial mixture of 0.1% indole-4-butyric acid (IBA) and 0.5% naphthalene acetic acid (NAA) (1000 and 5000 mg·L-1), IBA in talc formulation (1000 and 5000 mg·kg-1), IBA from concentrated acid form (1000 and 5000 mg·L-1), NAA from concentrate (1000 and 5000 mg·L-1), and an untreated control. With Dichorisandra hormone treatment had a significant effect on root number, root length, and maxillary shoot development. With Cestrum elegans only root number was significantly affected by chemical treatment. | |
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