Impact of Auxin Rates on Vegetative Growth and Nutrient Uptake of Ornamental Palm Varieties in Ogbomoso, Southwestern Nigeria

Ornamental palms are valued for their aesthetic appeal and landscape versatility, contributing significantly to urban greenery and nursery based horticultural enterprises. Despite their economic and ecological importance, vegetative growth and nutrient efficiency in palms are often constrained by suboptimal management practices, including inadequate use of plant growth regulators. This study evaluated the effects of different auxin growth hormone rates on vegetative growth and nutrient uptake of selected ornamental palm varieties in southwestern Nigeria. The experiment was conducted in a screen house at the Teaching and Research Farm, Ladoke Akintola University of Technology (LAUTECH), Ogbomoso. Factors considered were Three ornamental palm varieties (Queen palm, Golden palm, and Fan palm) subjected to five auxin rates (0, 0.2, 0.4, 0.6, and 0.8 ml/L) in a 3 by 5 factorial arrangement using a completely randomized design with six repetitions. Data on plant height, number of leaves, stem girth, and nutrient uptake were collected and analyzed using ANOVA and treatment means separated by least significance difference at 5% probability level. Results showed that auxin rates, variety, and their interactions significantly (p ≤ 0.05) influenced all measured growth parameters and nutrient uptake. The 0.6 ml/L auxin rate consistently produced superior vegetative growth, while 0.8 ml/L enhanced nitrogen and potassium uptake. Among the varieties, Queen palm exhibited the greatest overall height and leaf production, whereas Golden palm recorded the highest stem girth and nutrient assimilation efficiency. Significant interaction effects indicated that varietal responses were strongly dependent on hormone concentration and plant age. The study demonstrates that auxin application at 0.6 ml/L, enhances vegetative growth and nutrient uptake of ornamental palms, with Golden and Queen palms showing superior performance.