The Effect of Thiols and Rhizopon on the Rooting of Woody Stem Cutting of Punica granatum L.

Abstract

A research study was established to determine the effect of thiol compounds glutathione (GSH) and dithiothreitol (DTT) to induce rooting and root growth of woody stem cuttings from Punica granatum L., either alone or in combination with rhizopon. Woody cuttings of P. granatum 10 cm long were collected from 5-year-old potted greenhouse grown plants. No leaves were left attached on the cuttings. The proximal end of cuttings were dipped for 10 sec in 0.05 and 0.1 mM of GSH; 0.6, 1, and 2 mM of DTT followed by a 5-min rest, and immediately dipped in a solution of 1500 ppm of Rhizopon for 10 sec. Untreated cuttings were used as control as well as cuttings dipped only in 1500 ppm of Rhizopon for 10 sec. Rooting was continuous with bottom heating at 24 °C under greenhouse conditions. The experimental data was analyzed statistically using a completely randomized block design with five replications. The average total number of roots was increased when the cuttings were treated with the thiol compounds and Rhizopon, 52 days after treatment. However, DTT at 1.0 mM increased more significantly the average total number of roots than GSH at any concentration. The presence of DTT alone at 1.0 mM or with 1500 ppm of Rhizopon increased the average number of roots to 10.04 and 10.99, respectively. No significant difference was found for the treatment of 0.05 mM GSH and 1500 ppm Rhizopon showing average number of 12.11 roots. Significant average total root length was detected in cuttings treated with 1500 ppm Rhizopon compared to control, GSH at 0.1 mM, and DTT at 0.6 mM and 1.0 mM.