Abstract

ABSTRACTSugar content and freezing tolerance of protoplasts of Arabidopsis thaliana leaves were manipulated by incubating seedlings in a sucrose solution before protoplast isolation. Incubation in a 400 mM sucrose solution at 2 °C in the dark increased their freezing tolerance equivalent to that achieved after a conventional cold acclimation at 2 °C. The increased freezing tolerance was due to a decrease in the incidence of freeze‐induced lesions: expansion‐induced lysis (EIL) between −2 and −4 °C and loss of osmotic responsiveness (LOR) between −5 and −12 °C. The concentration of sucrose in the incubation medium required to minimize the incidence of the lesions was substantially different: 10–35 mM for EIL and 30–400 mM for LOR. Incubation in the sucrose solution at 23 °C decreased LOR only at −5 and −6 °C but less than that incubated at 2 °C, and there was no effect on EIL. Incubation in sorbitol solutions at 2 °C also decreased LOR at −5 and −6 °C but much less than in the sucrose solution. These results suggest that low concentrations of sucrose act as a metabolic substrate for the low‐temperature‐induced alterations required for the amelioration of EIL and, at higher concentrations, sucrose has a direct cryoprotective effect to minimize LOR.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call