Substances used as gelling agent alternative to the agar in culture media for in vitro propagation

<p align="left">The cultivation of plant fibers is achieved through the implementation of a group of techniques widely used for the propagation of plants <em>in vitro</em>. However, one disadvantage of these techniques is the high cost of components used for the crop’s medium, among these, the agar (primary gelling agent), has seen a price increase due to high demand. This article consults several studies regarding substances that have been utilized as alternative gelling agents, among which highlight starches (native or modified) and several plant gums and bacterial excretions that have been used in processes of organogenesis, embryogenesis and vegetative proliferation. The starches and gums studied showed favorable results in the <em>in vitro </em>cultivation of some plant species. The study demonstrates that both gums and starches may be potential substitutes (either partial or total) for agar, achieve a decrease in costs associated with starches, and have an ability to be chemically modified to improve gelling capacity.