Acclimation of croton and hibiscus seedlings in response to the application of indobultiric acid and humic acid for rooting

Abstract

The vegetative propagation of ornamental plants can be accelerated by applying plant growth regulators. Amongst
them, the use of auxins, plant hormones with physiological effects on cell elongation and rooting have stood out.
Alternatively, the application of humic acids, bioactive fraction of soil organic matter, also results in increases in
rooting cuttings of ornamental plants. The objective of this work was to study the growth characteristics and the
nutritional contents of croton and hibiscus plants during acclimation of seedlings in response to different
concentrations of indolebutyric acid (IBA) and humic acid (HA) applied to cuttings for rooting. The experiment was
conducted in greenhouse, and the apical stem cuttings were treated with solutions with concentrations of 0, 250,
500, 1000 and 2000 mg L-1of IBA and 0, 10, 20, 30 and 40 mg L-1 of C from HA. At 45 days of rooting in carbonized
rice husk, they were individually transferred to plastic bags of 2.0 dm3 containing a mixture of soil: sand: manure (2:
1: 1) as substrate. At 90 days of acclimation, the plants were collected for measurement of growth and nutritional
variables. The results showed that the application of the IBA stimulates the absorption of nutrients and growth of
croton cuttings and transplanted hibiscus, contributing to formation of vigorous seedlings. A similar response occurred
with the application of HA in hibiscus cuttings.