Cryopreservation of kiwi shoot tips

Area of Science:

• Plant Biotechnology
• Cryopreservation
• Horticulture

Background:

• In vitro plant propagation is essential for mass production of horticultural crops like kiwi.
• Cryopreservation techniques are vital for long-term germplasm conservation and genetic resource management.
• Optimizing cryopreservation protocols is critical for achieving high survival and regrowth rates in sensitive plant tissues.

Purpose of the Study:

• To investigate the impact of mother-plant physiological state and encapsulation-dehydration parameters on kiwi shoot tip cryopreservation.
• To establish an optimal cryopreservation protocol for kiwi (Actinidia spp.) shoot tips.
• To evaluate the post-cryopreservation viability and genetic stability of regenerated kiwi plantlets.

Main Methods:

• Shoot tips were collected from cold-acclimated mother plants (1 month at 5°C).
• Encapsulated shoot tips underwent preculture with increasing sucrose concentrations (0.5-1.0M) at 5°C.
• Desiccation to 26% moisture, prefreezing (-40°C at 0.2°C/min), and rapid immersion in liquid nitrogen were employed.

Main Results:

• Regrowth percentages for three kiwi accessions ranged from 22% to 56% after cryopreservation.
• No significant differences were observed between cryopreserved and control plantlets in leaf color, height, multiplication rate, or peroxidase zymogram patterns.
• The established protocol demonstrated effectiveness across different kiwi accessions.

Conclusions:

• The optimized encapsulation-dehydration protocol, including cold acclimation and specific cryoprotective treatments, is effective for kiwi shoot tip cryopreservation.
• Cryopreservation successfully preserved kiwi germplasm without inducing apparent phenotypic or physiological abnormalities in regenerated plantlets.
• This method provides a reliable tool for the conservation and propagation of kiwi genetic resources.