Effects of plant growth promoting bacteria and salicylic acid applications on rooting of oleander cuttings

This study investigated the effects of plant growth-promoting bacteria (PGPB) (strains KF3B, TV53D, KF63C) and salicylic acid (SA) on the rooting and shoot development of Nerium oleander L. cuttings. The research evaluated the impact of bacterial and SA treatments, alone and in combination, on key growth parameters, including rooting rate, number of roots, root length, root thickness, number of shoots, shoot length, and fresh and dry weights of shoots and roots. Results indicated that bacterial applications had significant positive effects on plant growth. The rooting rate in the control group was 70%, while it reached 50% with KF3B, 73.33% with KF63C, and 26.67% in the KF63C + SA combination. Notably, this combination had an adverse effect on rooting. Regarding root development, the longest root length (121.92 mm) was observed with KF3B, while the shortest (52.73 mm) was in the KF63C + SA treatment. For shoot development, KF3B yielded the highest number of shoots (3.67), whereas the lowest (1.18) was recorded in the KF63C + SA group. In conclusion, bacterial applications, particularly KF3B, promoted rooting and shoot development in N. oleander cuttings. However, certain combinations, such as KF63C + SA, had negative impacts, highlighting the importance of careful selection and application of PGPB and SA in plant propagation. Keywords: Bacteria, Rooting, Salicylic acid, Oleander