Effect of indole butyric acid on micrografting of cactus
Grafting is a common technique to propagate cacti species. Gymnocalycium mihanovichii is an ornamental plant and they should be grafted to root stock containing chlorophyll. In this research, exogenous auxin treatments were applied for grafting improvement. G. mihanovichii and Trichocereus spachianus were used as a scion and root stock, respectively. Indole butyric acid (IBA) was used as an auxin. Plants were treated with four different concentrations of IBA (0, 50, 100 and 150 ppm) and repeated at three different times (3, 9 and 15 days after micrografting). Measured parameters were scion height and diameter, cambial layer diameter, areole numbers, activated areole numbers and successful graft percentage. The histological studies were done on grafted plants with cross section. Auxin of 100 ppm was the most effective treatment to improve measured parameters. Auxin at the optimal concentrations, especially at 100 ppm, resulted in better vascular differentiation, an important process in grafting. Therefore, the optimal concentration of IBA was 100 ppm, especially when it was repeated three times. The obtained results from the present study indicated that IBA at the optimal concentration is an effective treatment, and may lead to increased successful grafts.
Key words: Gymnocalycium mihanovichii, Trichocereus spachianus, micrografting, hormone, auxin, areole, ornamental plant, vascular differentiation.