The influence of plant hormones on flowering and chlorophyll content of Leucadendron elimense E. Phillips subsp. elimense

Abstract

Overharvesting cut flowers and destroying natural habitats have forced Leucadendron elimense subsp. elimense, an endemic, fynbos shrub from the Agulhas Plain of South Africa to become an endangered species. Both male and female plants of this species are valued as floricultural products. Improvement of production methods could advance the sustainable and economic cultivation practices for a suitable and marketable product and further aid in the conservation of the species. The study aimed to determine the use of plant hormones on the fresh weight, flowering percentage, and chlorophyll content of the species. Plant material was sustainably harvested from randomly selected male and female plants growing in their natural habit. Experimental treatments consisted of a once-off application of Indole-3-acetic acid (IAA), 1-Naphthaleneacetic acid (NAA) and Indole-3-butyric acid (IBA) at selected concentrations of 2000, 4000 and 6000 ppm on male and female plants, respectively. Treated, terminal cuttings were planted into perforated, transparent, bags in a mix of two parts coarse river sand, one-part coco peat and one-part perlite (2:1:1) and grown under semi-controlled greenhouse conditions. Results of fresh weight and chlorophyll content showed significant increases in the flowering percentage of female plants using IAA at 4000 ppm, while lower concentrations (2000 and 4000 ppm) of NAA treatments were more successful on the male plants. The study presented that applying plant hormones enhanced the final product quality with evidence of improving the flowering for both cut and potted plant production of male and female plants. New scientific advances can successfully support the restoration ecology of red-listed species in a declining habitat.