Cytoplasmic glass formation in maize embryos

In order to examine the occurrence of a glassy state in the cytoplasm of maize embryos as a function of water content, isolated embryos were examined using spin-probe electron spin resonance. The glass transition temperature was determined at various degrees of hydration (h) in the range 0.05–0.25 g H2O g−1 dry sample weight. The obtained phase diagram indicates that, at standard storage temperature (−5°C), the cytoplasm of embryos drier than 0.15 g H2O g−1 is in a glassy state.