Morphological and Biochemical Properties, Leaf Nutrient Content, and Vase Life of Tuberose (Polianthes tuberosa L.) Affected by Root or Foliar Applications of Silicon (Si) and Silicon Nanoparticles (SiNPs)

Abstract

Although the presence of silicon (Si) as a phyto-beneficial element is not essential in the nutrition of ornamental plants, its application may have many advantageous effects. Therefore, the present research was conducted to investigate the effects of Si and synthesized silicon nanoparticles (SiNPs) on the morphological and biochemical properties, leaf nutrient content, and vase life of tuberose (Polianthes tuberosa L.). Si and SiNPs were applied at 200 mg L−1 and 400 mg L−1 via root or foliar application under greenhouse conditions. The results showed that the application of two silicon sources by foliar or root, with increasing leaf phosphorus and Si contents, substantially enhanced total soluble carbohydrate and protein. Morphological parameters, including leaf fresh weight, root volume, root and bulblet dry weight, flowering stem length, flowering-stem dry weight, and floret number were improved. The flower vase life in treated plants was longer than non-treated ones and ranged from 32% for 200 mg L−1 SiNPs by root application to 60% for 200 mg L−1 Si and 400 mg L−1 SiNPs by foliar. In most of the evaluated parameters, SiNPs had a relative superiority to Si, particularly when sprayed. A heat-map analysis of traits also revealed that the concentration of conventional Si has great prominence than its application method. In contrast, the method of applying SiNPs is more critical than its concentration. It is concluded that foliar application of SiNPs at 400 mg L−1 can be recommend for improving the growth and flowering of tuberose plants, although the root application of Si at 200 mg L−1 also had relatively acceptable results.