When you look at those little jars in a plant lab — with tiny green shoots or callus growing inside — have you ever wondered how the plants stay in place instead of floating in liquid?

That's because of something simple but essential: a gelling agent.


What Exactly Is a Gelling Agent

In plant tissue culture, or more specifically in plant cell or tissue culture experiments, the nutrient solution must be turned into a soft gel so that the plant material can rest on it, absorb nutrients, and grow evenly.

Without this gel-like support, cells would sink, float, or clump together, making growth unpredictable.
That's where gelling agents come in — they give the culture medium its structure and help create a stable environment for plant development.

The Traditional Choice: Agar

For decades, scientists have used agar, a natural polysaccharide extracted from red algae.
It's easy to handle, widely available, and produces a soft, moist gel that supports plant growth.

But agar also has its limitations:

  • Its composition can vary depending on the seaweed source.
  • Some batches may contain impurities that stress sensitive plant cells.
  • The gel tends to be slightly opaque, which can make it harder to observe roots and callus formation.

Even so, agar remains the classic gelling agent — simple, reliable, and good enough for many routine tissue culture tasks.

The Modern Alternative: Gellan Gum

In recent years, many laboratories have shifted toward gellan gum — a microbial polysaccharide produced by fermentation.
Compared with agar, gellan gum forms clearer, firmer, and more consistent gels at lower concentrations, typically around 2.5–4 g/L.
It also reacts to ions such as calcium and magnesium, allowing scientists to adjust the firmness of the gel according to the needs of the plant species.

Because of these features, gellan gum is now widely used in plant tissue culture, plant cell culture, and micropropagation.
You might come across it under trade names like Gelrite, Phytagel, or CINOGEL gellan gum from CINOGEL Biotech — known for providing high-purity materials used in laboratories worldwide.

Why the Choice Matters

The difference between agar and gellan gum may look small, but it can have a big impact on in vitro plant growth:

  • Clear gels make it easier to observe roots, shoots, and contamination.
  • Consistent texture ensures more reproducible experimental results.
  • Lower levels of impurities lead to healthier and faster-growing plantlets.

So the next time you see a jar of plant tissue culture in the lab, remember that those small green shoots are supported by more than just nutrients.
The quiet but crucial foundation of the whole system is the gelling agent — the invisible matrix that makes plant cell culture possible.