Hydrogel Systems in Plant Germplasm Cryopreservation: A Comprehensive Review

Area of Science:

• Plant Science
• Biomaterials Science
• Cryobiology

Background:

• Cryopreservation is vital for conserving plant genetic resources, especially for clonally propagated crops, endangered species, and recalcitrant-seeded plants.
• Hydrogel encapsulation offers mechanical support, controlled dehydration, and regulated cryoprotectant uptake, improving plant survival during ultra-low-temperature storage.
• Traditional calcium-alginate beads are being advanced by novel hydrogel systems, including composite polysaccharides, protein matrices, synthetic polymers, and functionalized hybrids.

Purpose of the Study:

• To review current knowledge on hydrogel platforms for plant cryopreservation.
• To analyze how hydrogel physicochemical properties impact dehydration, cryoprotectant transport, vitrification, and rewarming.
• To identify limitations and outline design principles for next-generation hydrogel systems.

Main Methods:

• Synthesis of current research on hydrogel-based plant cryopreservation techniques.
• Assessment of hydrogel performance across various plant explant types.
• Analysis of material properties influencing cryopreservation efficacy.

Main Results:

• Engineered hydrogels offer enhanced control over water state, pore architecture, diffusion, and thermal properties, reducing cryoinjury.
• Advanced hydrogel systems demonstrate improved post-thaw recovery in diverse plant explants compared to traditional methods.
• Physicochemical properties of hydrogels critically influence dehydration dynamics, cryoprotectant transport, and vitrification stability.

Conclusions:

• Hydrogel encapsulation is a promising strategy for improving plant cryopreservation success rates.
• Future advancements require material standardization, integration with automation, and development of responsive hydrogels for stress mitigation.
• Next-generation hydrogels hold potential for more effective and widespread plant germplasm conservation.