Growth regulators on the shooting and rooting of Tamarix chinensis stem cuttings

Tamarisk (Tamarix chinensis) is a halophyte that plays a critically important role in the restoration of saline land. It reproduces via seeds, but the germination rate of seeds is low in its natural environment, which greatly limits its ability to spread. Vegetative propagation is a useful method for enhancing the quality and reproduction of plants, and the effects of growth regulators on stem cuttings vary. Here, we evaluated the effects of different concentrations (0, 100, 250, 500, 1,000, 1,500, 2,000, and 3000 mg L−1) of gibberellin A3 (GA), indole-3-butyric acid (IBA), naphthaleneacetic acid (NAA), and 6-benzylamine purine (BAP) on the survival, shoots, and root formation of tamarisk stem cuttings. The survival of tamarisk stem cuttings was 100% in the 100 mg L−1 GA, 1000 mg L−1 IBA, and 500 mg L−1 BAP treatments. The highest number of new shoots per cutting was observed in the 1000 mg L−1 IBA treatment and three times higher than in the control (0 mg L−1; CK), only significant difference with the 250 mg L−1 NAA treatment. The fresh weight of the shoots and roots was higher in the 100 mg L−1 GA, 1000 mg L−1 IBA, 500 mg L−1 BAP, and 250 mg L−1 NAA treatments, and was 161%, 200%, 114%, 66% and 150%, 300%, 150%, 183% higher than in the CK, respectively. Although, the fresh weight of the shoots and roots was highest in the 1000 mg L−1 IBA treatment, it is only significantly differed from that in the 500 mg L−1 BAP and 250 mg L−1 NAA treatments in the fresh weight of the shoots. No significant differences in root length and diameter were observed in the 100 mg L−1 GA, 1000 mg L−1 IBA, 500 mg L−1 BAP, and 250 mg L−1 NAA treatments. Root surface area and volume were significantly higher in the 250 mg L−1 NAA treatment than in the 1000 mg L−1 IBA and 500 mg L−1 BAP treatments. Overall, growth regulators significantly affected the shooting and rooting ability of tamarisk stem cuttings. The following treatments were the most effective for enhancing the quality of tamarisk stem cuttings: 100 mg L−1 GA, 1000 mg L−1 IBA, 500 mg L−1 BAP, and 250 mg L−1 NAA. The growth of tamarisk stem cuttings was maximized in the 1000 mg L−1 IBA treatment, and the survival of tamarisk stem cuttings was lowest in the 250 mg L−1 NAA treatment. This study provides a theoretical basis and data support for the technology of growth regulators on the shooting and rooting of tamarisk stem cuttings.