STORAGE OF ISOLATED CHLOROPLASTS WITHOUT LOSS OF PHOTOCHEMICAL ACTIVITY

Abstract

Fragmented spinach chloroplasts were stored for one year in 0.5 M sucrose at −40 °C. with almost negligible losses of photochemical activity. Thawed chloroplasts and freshly isolated chloroplasts showed similar rates of deterioration at 10 °C. Washed chloroplasts did not show as high retention of activity during low temperature storage as crude chloroplast suspensions. High retentions of activity were observed with chloroplasts from different plant species, as well as with different oxidants. The activities of subsamples that were frozen and thawed in a standard way agreed within 5%. Deterioration during lyophilization of chloroplasts occurred chiefly during the early stages of drying, and was lessened by sucrose. The stability of lyophilized chloroplasts in storage varied directly with the degree of desiccation and inversely with the storage temperature; little deterioration occurred in thoroughly dried chloroplasts during lengthy storage at or below 5 °C.