The 2009 ASHS Annual Conference

An experiment was conducted to determine if orchid liners accumulate silicon and if this element can affect seedling growth and development. A total of 800 liners were evaluated, by applying silicon (AgSil 25) as a drench with three treatments (0.5%, 1.0%, and 2.0%) and a control (no Si fertilization). AgSil 25 affected the pH of the growing medium, % Si content of the plant and overall development of Phalaenopsis liners.  Both pH and % Si increased significantly over the control with increasing rates of AgSil 25. Silicon applied at 1% significantly increased whole plant dry weight, shoot fresh and dry weight, and root dry weight over the control whereas at 0.5% only shoot fresh weight, root dry weight and root length were increased.  Other plant parameters evaluated, such as leaf number, leaf size, and chlorophyll, were not affected by the application of silicon.  The data obtained from this experiment demonstrated that Phalaenopsis orchid liners are accumulators of silicon, and that this element may influence their growth and development.  Further studies are needed to address the beneficial effects of Si fertilization on the lifecycle of Phalaenopsis up to flowering.  Especially since important horticultural traits such as plant growth rate, size, flower initiation, development and quality could be enhanced by the uptake of silicon.  In addition, the effects of silicon fertilization on reducing abiotic (i.e. temperature, light and edema) and biotic (i.e. plant disease) stresses are warranted because of the potential positive impact for the orchid industry.