Modeling of the respiration rate and gene expression patterns of cabbage in response to mechanical impact stress using a modified Weibull distribution

• Response characteristics of cabbage to mechanical stress application were examined.
• Impact stress (dropping) affected the changes in physiological and chemical attributes of cabbage.
• Impact stress increased expression of stress-responsive genes in cabbage leaf.
• MWD model is suitable for describing stress response characteristics of cabbage.

We previously found that respiration rate changes of postharvest cabbage heads are influenced by the mechanical (impact) stress level and the time since the stress application. In this study, the effect of impact stress (dropping treatment) on the expression of genes related to respiratory byproducts and ethylene synthesis of the cabbage was investigated. Quantitative reverse transcription PCR (qRT-PCR) analysis revealed that cabbage leaf wounds caused by dropping treatment significantly increased the expression of genes (BoAPX2, BoPAL, BoSAMS, and BoACS2) in the wounded area and the surrounding leaf area within 1 h after the treatment. Additionally, we proposed a novel mathematical model based on a modified Weibull distribution (MWD) to describe the stress response characteristics of the cabbage. Using a non-linear least square method, the proposed prediction model fitted the respiration rate and relative gene expression experimental data very well. The model parameters are also clearly defined and discussed. The results, therefore, suggest possible uses of the model for predicting the stress-responsive cellular metabolisms and quality changes of postharvest fresh produce. Furthermore, this model has potential to become valuable tool for developing the postharvest techniques to minimize quality loss and to extend the shelf-life of fresh produce.