Dendrobium sp. (Orchidaceae) is the most ‘in demand’ cut flower in the export and local market due to its vivid and variable flower coloration. However, the production of quality flowers is a major obstacle and is the main factor contributing to the export potential of the cut flower industry in Sri Lanka. This research was focused on improving floricultural quality, growth and enhancing disease resistance of Dendrobium by preharvest application of soluble silicon.
The experiments were conducted in a mesh house at 50% shade and were designed as a Completely Randomized Design (CRD). Each treatment or control plant consisted of 12 replicates and the experiment was repeated twice. The orchid plants were potted in clay pots and provided with 100 mg/L of sodium silicate at weekly intervals, showed significantly higher shoot length, leaf length and number of leaves compared to silicon provided bi-weekly or in the controls. Plants grown in a newly designed aeroponic system and treated with 100 mg/L silicon weekly showed significantly improved floricultural quality traits: a higher number of flowers per spike and higher spike length, higher spike thickness and higher flower length and diameter compared to the plants treated at 50 mg/L or untreated plants.
Natural disease development of leaf spot disease was significantly lower in plants treated with silicon as compared to the control. The average leaf thickness, cuticle thickness and total soluble phenol content were significantly higher in plants treated with silicon. These results indicate that mechanical barriers in the form of cuticle thickness and leaf thickness contribute towards the reduction of disease development. Increased levels of total soluble phenols in leaves of silicon treated plants may be also contributing biochemically towards warding off disease.
How to Cite:
Weerahewa, D., 2016. Floricultural Quality Traits and Probing Mechanisms of Silicon Mediated Disease Resistance of Dendrobium. OUSL Journal, 10, pp.23–40. DOI: http://doi.org/10.4038/ouslj.v10i0.7333