Modeling Methodology for Cold Tolerance Assessment of Pittosporum tobira

Abstract

Abstract: This study was carried out to develop a simple, rapid and reliable assessment model to predict cold tolerance in Pittosporum tobira, a broad-leaved evergreen commonly used in the southern region of South Korea, which can minimize the possible experimental errors appeared in a electrolyte leakage test for cold tolerance assessment. The modeling procedure comprised of regrowth test and a electrolyte leakage test on the plants exposed to low temperature treatments. The lethal temperatures estimated from the methodological combinations of a electrolyte leakage test including tissue sampling, temperature treatment for potential el ectrical conductivity, and statistical analysis were compared to the results of the regrowth test. The highest temperature showing the survival rate lower than 50% obtained from the regrowth test was -10°C and the lethal was -10°C~-5°C. Based on the results of the regrowth test, several methodological combinations of electrolyte leakage tests were evaluated and the electrolyte leaka ge lethal temperatures estimated using leaf sample tissue and freeze-killing method were closest to the regrowth lethal temperatur e. Evaluating statistical analysis models, linear interpolation had a higher tendency to overestimate the cold tolerance than non- linear regression. Consequently, the optimal model for cold tolerance assessment of P. tobira is composed of evaluating electrol yte leakage from leaf sample tissue applying freeze-killing method for potential electrical conductivity and predicting lethal temp erature through non-linear regression analysis.Additional key words: