Vacin and Went (VW) Medium: A Go-to Solution for Orchid Tissue Culture
When it comes to the art and science of plant tissue culture, the growth medium plays a pivotal role in ensuring the success of culturing. Among the many specialized media developed for plant tissue culture, the Vacin and Went (VW) medium stands out, especially in the context of propagating orchids and other monocots.
In this blog post, we’ll take a closer look at the Vacin and Went medium, explore its applications in tissue culture, particularly with orchids, and provide its formulation on a per-liter basis.
What is Vacin and Went Medium?
The Vacin and Went (VW) medium was first formulated by E.F. Vacin and F.W. Went in 1949. It was specifically developed to support the growth of orchid seedlings in vitro (in a controlled environment outside of their natural habitat). Orchids require a nutrient-rich and balanced environment for successful tissue culture propagation. The VW medium offers just that, providing the necessary macronutrients, micronutrients, and growth factors required for optimal growth.
Over time, the medium has proven to be ideal for culturing not just orchids, but a wide range of other monocots (plants with one seed leaf) and, in some instances, dicots (plants with two seed leaves) as well.
Applications of Vacin and Went Medium
The VW medium is predominantly used for:
Orchid Seed Germination: Orchid seeds are extremely tiny and lack stored nutrients, making in vitro germination on a specialized medium like VW ideal for their growth. The medium supplies critical nutrients that help seeds develop into healthy seedlings.
Shoot and Root Induction: VW medium is used for tissue culture techniques like organogenesis to regenerate shoots and roots. By adding specific plant growth regulators (e.g., auxins and cytokinins), VW medium allows for the selective induction of plant parts, which is essential for micropropagation techniques.
Protocorm-Like Body (PLB) Formation: For certain orchids, tissue explants can be cultured on VW medium to develop protocorm-like bodies, from which complete plantlets can be regenerated.
Somatic Embryogenesis: While VW medium is widely used for orchid micropropagation, it can also support somatic embryogenesis, allowing for developmental plasticity where cultured tissue can form embryo-like structures.
- Propagation of Other Monocots: While primarily tailored for orchids, VW medium has been successfully used for culturing other monocotyledons such as lilies, bromeliads, and even ferns.
Formulation of Vacin and Went Medium (Per Liter)
The VW medium is composed of minerals, vitamins, and in some cases, plant growth regulators to support orchid growth. Here’s the base formulation of the Vacin and Went medium on a per-liter basis:
| Component | Concentration (mg/L) |
|---|---|
| Calcium Nitrate (Ca(NO₃)₂·4H₂O) | Ca 300 mg/L, N 350 mg/L |
| Potassium Phosphate (KH₂PO₄) | 200 |
| Magnesium Sulfate (MgSO₄·7H₂O) | 250 |
| Ferrous Sulfate (FeSO₄·7H₂O) | 15 |
| Manganese Sulfate (MnSO₄·H₂O) | 10 |
| Sodium Molybdate (Na₂MoO₄•2H₂O) | 1 |