Modelling desiccation sensitivity by integration of stress intensity and duration effects in flash-dried embryonic axes and zygotic embryos of recalcitrant seeds

摘要

The modified inverse hyperbolic (MIH) model, described by Pammenter et al. (2003), was applied to flash drying data of excised embryonic axes/zygotic embryos of 20 recalcitrant-seeded species. Percentage root, shoot and seedling production were used as measures of viability. The area above the drying curve was calculated by integration of the function describing the drying kinetics and evaluating the integral between the limits of zero drying time and the drying time corresponding to 50% viability retention (P-50); the resultant value was used as a desiccation stress index (DSI) to rank species. Additionally, an exponential and second order polynomial (SOP) function were applied to the drying data, and these functions were similarly integrated to calculate DSI values. All three models fitted the data satisfactorily, and there was a strong positive correlation between the DSI values calculated using each model. Monocotyledonous species were seen to be ranked in similar order, while similar dicotyledonous species combinations were present at least sensitive and most sensitive extremities of the rankings generated using the different models. The MIH model proved to be the most suitable model for quantifying desiccation sensitivity across a wide range of recalcitrant-seeded species showing different drying kinetics.