null on Orchid
Quick answer
If your Orchid has null, the most likely cause is: Plant tissue culture morphogenesis is controlled by the balance between auxin and cytokinin hormones — auxin-dominant media promote root formation while cytokinin-dominant media promote shoot formation, with the ratio directly determining developmental outcomes.
Start here:
- 1. 1. For root initiation: use auxin-dominant medium with NAA or IBA at 0.1-10 mg/L
- 2. 2. For shoot initiation: use cytokinin-dominant medium with BAP at 0.5-2 mg/L
Why Orchid gets null
Phalaenopsis spp.
Plant tissue culture morphogenesis is controlled by the balance between auxin and cytokinin hormones — auxin-dominant media promote root formation while cytokinin-dominant media promote shoot formation, with the ratio directly determining developmental outcomes.
How to reverse null on Orchid
- 1
1. For root initiation: use auxin-dominant medium with NAA or IBA at 0.1-10 mg/L
- 2
2. For shoot initiation: use cytokinin-dominant medium with BAP at 0.5-2 mg/L
- 3
3. Maintain 1:1 ratio for callus induction; adjust ratio based on desired morphogenetic outcome
- 4
4. Transfer plantlets to hormone-free medium for final hardening phase
Keep null off this Orchid
Monitor auxin-to-cytokinin ratio throughout culture cycle and adjust based on target organ. Higher auxin relative to cytokinin drives rhizogenesis; higher cytokinin drives caulogenesis.