Plant tissue culture – micropropagation
BiologyBiotechnologyAges 15–16
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Biotechnology
A leaf tissue explant is cultured on a medium containing auxin and cytokinin. Drag the two hormone concentrations to see how the auxin/cytokinin ratio determines whether the explant forms callus, shoots or roots; increase the number of subculture cycles to see plantlet numbers multiply exponentially compared with traditional cuttings, and see what happens when the technique is not sterile.
Lesson: Cell technology and its applications
What it shows
Plant tissue culture relies on totipotency: under the right conditions a single plant cell can regenerate a whole plant. Here a leaf explant grows on a sterile medium containing an auxin and a cytokinin, and the ratio between them decides the outcome: a roughly balanced ratio gives undifferentiated callus, more cytokinin gives shoots, and more auxin gives roots. In micropropagation, shoot clusters are divided and subcultured repeatedly, so plantlet numbers grow exponentially, and all plantlets are genetically identical to the parent. Contamination by fungi and bacteria, which thrive on the sugar-rich medium, is a common cause of failure.
How to use
Drag Auxin (NAA) and Cytokinin (BAP) and watch the explant and its position on the hormone chart move between callus, shoots and roots. Once shoots form, raise the Number of subcultures and read the plantlet count from one explant. Finally switch off Sterile technique to see how contamination at each subculture reduces the number of healthy jars.
Parameters you can change
- Auxin (NAA) 0–3 mg/L
- Cytokinin (BAP) 0–3 mg/L
- Number of subcultures 0–8
- Sterile technique
Questions to explore
- How should the auxin-to-cytokinin ratio be changed to make shoots form roots before planting out?
- How many plantlets can one explant give after 5 subcultures, and why does the number grow exponentially?
- Why does the sugar-rich medium become contaminated so easily when technique is not sterile?
