In the following experiments, however, the main concern was to see whether or not silicon had any beneficial effects on aspects of plant shape and size. Rooted cuttings of several floricultural crops were planted into a commercial, peat-based compost and grown on in a glasshouse at 22/18 degsC day/night temperatures.
The compost contained some silicon and the plants were all irrigated with tap water that also contained some silicon. The main treatment was to apply supplementary silicon as a weekly drench of 250ml of a solution containing 100mg of silicon per litre. Control plants did not receive any supplementary silicon.
Many species, including Agyranthemum frutescens, Petunia x hybrida and Calibrachoa, accumulated significantly more silicon in their leaves when it was supplied in a drench. But the accumulated silicon had relatively little impact on the shape and size of most parts of most species.
The flowers of treated plants of Fuchsia hybrida 'Marinka', in contrast, were significantly bigger and treated plants of Bracteantha and Lobelia were significantly heavier than their controls.
Potassium Silicate Drenches Increase Leaf Silicon Content and Affect Morphological Traits of Several Floriculture Crops Grown in a Peat-Based Substrate by Mattson and Leatherwood (2010). HortScience 45 (1): 43-47. ISHS members can view HortScience at the website www.ishs.org
Dr Ken Cockshull is Emeritus fellow at Warwick HRI