Effects of Different Types and Concentrations of Auxins on Juvenile Stem Cuttings for Propagation of Potential Medicinal Dillenia suffruticosa (Griff. Ex Hook. F. and Thomson) Martelli Shrub

Abstract

A method for the vegetative propagation of Dillenia suffruticosa with important cultural, medicinal and ecological values was developed. Juvenile stem cuttings were collected from wild populations in Brunei Darussalam. The cuttings with or without leaves were treated with Indole Butyric Acid (IBA), Naphthaleneacetic acid (NAA), or Indole Acetic Acid (IAA) at 0, 0.01, 0.05, 0.10, or 0.20% (w/v) using a quick-dip method, planted in rooting media and kept in a misted greenhouse. The survival and rooting percentages, number and length of new roots produced, number and area of leaves and Relative Growth Rate (RGR) based on stem length and stem diameter were assessed at a 4-week interval for 24 weeks. The leafless cuttings and leafy cuttings treated with distilled water after week 4 and 16, respectively, did not survive. All of the leafy stem cuttings treated with 0.10 and 0.20% NAA and 0.20% IAA survived for 24 weeks. Leafy stem cuttings treated with 0.10 and 0.20% NAA and not ABA had formed significantly more and longer roots than cuttings in the other treatments at week 8. Leafy stem cuttings treated with 0.10% IAA had more new leaves and greater leaf area, than cuttings in the other treatments at week 8. There were no significant differences in the RGR of leafy stem cuttings among the different treatments at week 8. This study demonstrates that treatments with 0.10-0.20% NAA and 0.10% IAA and not IBA resulted in the development roots and shoots from leafy stem cuttings and can be used for the mass production of D. suffruticosa plantlets, which will prevent the over exploitation of wild stocks.