Tissue Culture of Kiwifruits (Part 2)

Table of Contents

Background From Part 1

In part 1 of the tissue culture of kiwi we covered some facts on kiwi, their conventional technique, and in vitro propagation of Actinidia deliciosa using the nodal stem as explant. But, different regions have different species of kiwi or Actinidia. Therefore, stem explant might not work for your plant.

So, if you are working with a different species of kiwi and facing the aforementioned case, then you must know stem is not the only explant that has been tested to grow kiwis. Several other explants have been successfully used in tissue culture to grow or regenerate a whole kiwi plant.

This article brings you a brief on what other explants and tissue culture techniques have been used in the past to grow kiwis around the world under in vitro conditions. So, let’s dig in!

In Vitro Approaches to Grow Actinidia (Kiwi) species

Meristem and Shoot Tip Culture

Kiwis have been tested to grow in different media that include MS (Murashige & Skoog) media, Gamborg B5 media, and Cheng’s media. But of all these media, more successful cultures have been observed in full strength MS media.

Given below is a three-step procedure of meristem culture taken from the study of Revilla, M. A., Rey, M. A., Gonzalez-Rio, F., Gonzalez, M. V., Diaz-Sala, C., & Rodriguez, R. (1992). Micropropagation of Kiwi (Actinidia spp.). High-Tech and Micropropagation II,

Meristem tip culture was first developed for Actinidia chinensis. The three stages of this process include:

• Place the meristem tip of 0.2 to 0.5 mm long in a container containing the media composition given below for different stages. Place the cultures in the dark overnight and then transfer them to a growth room at 24 ± 1°C. After 20-40 days, 5-10 mm rosettes with 4-10 leaves will be obtained.
• Transfer rosettes to the culture vessel containing proliferation medium. And, maintain the cultures at 24°C and 16 h photoperiod.
• When shoots reach the height of 3-3.5 cm with 2-4 leaves, transfer them to the rooting media.

Related: Tissue Culture Using Blueberries

Culture Using Axillary Bud Explant

• A study by Shen et al. shows the culture initiation from single node explants on MS media supplemented with 2 uM BA.
• Then, shoot multiplication was achieved by transferring explants to MS media supplemented with 1 mg/L 1 BA together with 0.1 mg/L IAA.
• Then 20 mm shoots were transferred to a rooting medium containing 1 mg/L IAA.

Culture Using Stem Nodal Explant

• A study by Kamenicka and Rypak showed the multiplication of Kiwi stem nodes using MS medium containing 2.mg/L GA3 and 1.mg/L BA. The cultures were maintained at day/night temperatures of 24/208C under 16.h photoperiod. When the shoots grow, they are treated with10 mg/L IBA or 20 mg/L for 5 minutes. Rooting can also be induced by transferring the shoots to a rooting medium containing 1 mg/L IBA supplemented with 0.1% activated charcoal.
• The other technique developed by Wiyaporn et al. showed culturing Kiwi on MS medium supplemented with BA and 2iP at 1-7.mg/L using stem segments, nodes, or petioles as explants.

Culture using Leaf Explant

• A study by Pais et al showed the effective culturing of Kiwi (A. chinensis) by using petiole segments. He cultured petiole segments on MS medium supplemented with sucrose 20.g/L and 1.mg/L zeatin/0.025.mg/L IAA. The differentiation of tissues was obtained after transferring them to half-strength MS media. Then, rooting was induced by soaking the basal cutting surface of plantlets in 20.mg/L IBA for 24.h followed by immediate potting.
• In the other study performed by Gonzalez et al., the callus formation was induced by keeping petiole explant on, Cheng's K(h) containing 0.1.uM IAA, 4.5.uM zeatin, and 2% sucrose. The same media was used for the maintenance of culture and shoot bud formation. After shoots are observed, the roots were obtained by immersing the shoots in 5 mM IBA solution for 15 sec and then subsequently cultured in half-strength K(h) basal medium.

Culture using Root Explant

• In 1991, Chiariotti et al. regenerated shoots and roots using root explant of A. deliciosa. He cultured the explant on Ms medium containing 2 mg/L 2iP.
• In another study published by Kumar and Sharma, regeneration of whole plants using root explants on Ms media supplemented with 2 mg/L BA and 0.1 mg/L IBA were reported.

Culture using Endosperm Explant

• Endosperm as an explant was used by Gui et al. in 1992. Here, the callus was induced from the endosperm of Kiwi on a basic MS medium supplemented with 3.mg/L zeatin, 0.5 mg/L 2,4-D, and 400 mg/L cycloheximide. Then, the callus was transferred to a fresh medium prepared by using MS medium supplemented with 1 mg/L zeatin and 400 mg/L cycloheximide. After 15 days, embryoids were observed that further developed into plantlets.

All the studies mentioned here are taken from a published review article by Kumar, S., & Sharma, D. R. (2002). Review Article In vitro propagation of kiwifruit. The Journal of Horticultural Science and Biotechnology.

Let us know on our given email ID if any of these protocols work for you! We will be happy to share your tissue culture success story on our social media platforms, reaching culturists worldwide. Subscribe to www.plantcelltechnology.com now to get the recent updates on different innovative blogs and videos on tissue culture to stay ahead in your experiments!

Happy culturing!!

Written by: Anjali Singh

Anjali is a scientific content writer at PlantCellTecnology. She has joined the company in 2020 with her technical knowledge of tissue culture, a background in Plant Biotechnology, and research skills. Apart from writing educational articles for our tissue culture enthusiasts, she also helps them with their queries on the tissue culture processes.

Before joining PCT, she has worked with various other biotech industries as a Scientific content writer and holds good experience in laboratory work and research.

References

1. Kumar, S., & Sharma, D. R. (2002). Review Article In vitro propagation of kiwifruit. The Journal of Horticultural Science and Biotechnology, 77(5), 503–508. doi:10.1080/14620316.2002.11511530.
2. Revilla, M. A., Rey, M. A., Gonzalez-Rio, F., Gonzalez, M. V., Diaz-Sala, C., & Rodriguez, R. (1992). Micropropagation of Kiwi (Actinidia spp.). High-Tech and Micropropagation II, 399–423. doi:10.1007/978-3-642-76422-6_21.