Adverse Effects of Salt Stress on Rootability of Rosmarinus officinalis Cuttings and their Alleviation by Indole-3-Butyric Acid (IBA) and Bacillus subtilis

Abstract

(Received 26/10/2019, accepted 21/12/2019) DOI: 10.21608/ejoh.2019.18698.1121 ©2019 National Information and Documentation Centre (NIDOC) THIS STUDY was conducted at the Horticulture Farm, Faculty of Veterinary and Agricultural Science, El-Zawia University, Libya during 2014 and 2015 seasons, to investigate the effect of indole-3-butyric acid (IBA) concentrations (0, 50 and 100 ppm) alone or in combination with Bacillus subtilis on the rootability, root and shoot growth of Rosmarinus officinalis L. cuttings under salt stress conditions (control, 1000, 2000 and 4000 ppm NaCl). The obtained data revealed that irrigation of cuttings with NaCl at 2000 and 4000 ppm resulted in a significant reduction in rooting percentage, root and vegetative growth characteristics, contents of N, P and K as well as C/N ratio in cutting tissues compared to control and the lowest salinity level used, whereas Na % and Na/K ratio were high, especially at high salinity levels. Treatment of cuttings with IBA alone or combined with B. subtilis modified and alleviated most of the harmful effects of salt stress, especially at the lower salinity level. Generally, the combination of IBA at 50 ppm with B. subtilis had a profound effect in increasing rootability, root and vegetative growth characteristics of plants compared to the control and all other treatments. The same treatment increased contents of N, P and K as well as C/N ratio, whereas reduced Na % and Na/K ratio in the rooted cutting tissues. So, it could be recommended to use this treatment for alleviation of adverse effects of irrigation water salinity on rooting and growth of R. officinalis cuttings.