Healing of Gladioulus grandiflora corms under refrigeration and Fusarium oxysporum infection

Background. The production and marketing of flower and ornamentals have increased in the world. However, about 50% of this production is lost due to injuries caused by precarious harvesting, transportation and storage, which facilitates tissue infection. The objective of this research was to characterize wound healing in refrigerated Gladioulus grandiflora corms and how this affects the entry and establishment of Fusarium oxysporum infection. Methods. Gladioulus grandiflora corms were injured and stored at 12 ± 4 °C and a relative humidity of 90 ± 5%. Phenolic compounds, tissue darkening (melanin formation), lignification, suberization, resistance to infection, loss of fresh mass and respiratory rate were evaluated during healing of G, grandiflora corms. Results. Injury to G. grandiflora corms caused cellular decompartmentalization and death, increasing the fresh mass losses and triggering oxidase activities by exposing enzymes to substrates and O₂. Discussion. Cells adjacent to the wound underwent healing in a temporal sequence, starting with an increase in respiration rate, formation of carbon skeletons that increase the concentration of phenolic compounds used for the synthesis and deposition of lignin, melanin, and suberin in injured tissues. Conclusion. These processes resulted in G. grandiflora corm healing by accumulation of lignin, melanin and suberin in wounded tissues, which sealed corm against water loss and F. oxysporum entrance by the third day after injury.