The role of hydrogen peroxide in cryopreservation of cockscomb (Celosia plumosa) seedlings

Recently, many researches showed that oxidative stress is a potential cause of damage in plant cells during cryopreservation, and hydrogen peroxide (H₂O₂) may be the leading reactive oxygen species (ROS) components.
However, H₂O₂ is not only being a toxic by product causing oxidative damage to membrane lipids, protein and DNA at high concentrations, but also involving in signal transduction pathways leading to activate the plant defense against biotic and abiotic stresses at low concentrations.
The effects of H₂O₂ in cryopreservation were investigated in the present study by adding H₂O₂ or CAT in each step of cryopreservation, detected the dynamic changes in antioxidant systems during cryopreservation of cockscomb seedlings.
The results showed that: 1) the process of cryopreservation resulted in the rise of H₂O₂, and it reached the peak after unloading; 2) addition of either low concentration of H₂O₂ or CAT can improve the regeneration rate of cryopreserved cockscomb seedlings, while sthe addition stages were different.
Adding 4 µmol L^-1H₂O₂ in loading stage got 73.33±3.52% regeneration rate, and adding 200 U mL^-1 CAT during the unloading process resulted in 76.67±4.17% regeneration rate; and 3) the addition of H₂O₂ in loading phase increased the activity of CAT in the seedlings, resulting a sharp drop of H₂O₂ content at PVS2 stage and the continuous decline of MDA content after freezing.
Therefore, we conclude that adding low concentration of H₂O₂ at early cryopreservation steps improves cockscomb seedlings’ cryo-tolerance by enhancing the antioxidant capacity, which prevents ROS accumulation.

III International Symposium on Plant Cryopreservation

B.L. Li, M. Zhang, X.Z. Wang, X.R. Jiang, Y. Liu

cryopreservation, H₂O₂, antioxidant, hydrogen peroxide, Celosia, ROS

https://doi.org/10.17660/ActaHortic.2019.1234.9