Freezing of isolated thylakoid membranes in complex media. VIII. Differential cryoprotection by sucrose, proline and glycerol

摘要: The cryoprotective efficiency of sucrose, proline and glycerol for chloroplast membranes isolated from spinach leaves (Spinacia oleracea L. cv. Monatol) was determined after freeze-thaw treatment in media containing the predominant inorganic electrolytes stroma. In most cases, protective capacity equimolar concentrations cryoprotectants followed order sucrose > glycerol. lower freezing temperature less cryoprotectant necessary comparable preservation photosynthetic electron transport. Likewise, cyclic photophosphorylation light-induced proton gradient increased with decreasing temperature. contrast, while effectively stabilized these membrane reactions at mild moderate temperatures, it much efficient more severe stress. Cryoprotection formation given initial largely independent While dissociation peripheral part coupling factor (CF1) during cannot be prevented presence and. latter may stabilize this protein complex least under conditions. differences solutes are discussed relative to their non-ideal activity-concentration profiles, solution properties penetration behaviour across thylakoid membrane.