Plant tissue culture takes place in three-dimensional space. Callus cells, singly or in very small clusters, can be grown in liquid media, but for shoots to extend up and then roots to grow down, the callus cells are plated on a semi-solid gel surface. We offer a variety of gelling agents to allow the researcher to optimize the regeneration conditions for each species. The gelling agent of choice may change with the stage of the plant development. Agar is often the first choice to solidify the nutrient culture medium. It is a natural polysaccharide product extracted from red algae seaweed.. We offer agar choices that differ in degree of purity as well as gelling temperature, trace element composition, ash content, and pH. Agarose, the gelling component of agar, may be used in suspension cultures as well as gels. PhytagelTM ,our bacterially produced polysaccharide composed of glucuronic acid, rhamnose, and glucose, is a superior replacement for agar in some cases. Phytagel is clear, colorless, and makes a high strength gel. AgargelTM blends Phytagel with agar. Alginic acid, extracted from brown algae, is used to encapsulate protoplasts.