英语翻译Maintenance of polyunsaturated fatty acid levels inchlor

英语翻译Maintenance of polyunsaturated fatty acid levels inchloroplast lipids has been shown to contribute to lowtemperature survival and the normal formation ofchloroplastmembranes under chilling stress (Routaboulet al.2000; Iba 2002).Both the Arabidopsis fad5mutant,which lacks an active chloroplast x-9 fatty aciddesaturase and accumulates high levels of palmitic acid(16:0),and the fad6 mutant,which lacks an active x-6fatty acid desaturase and accumulates high levels ofpalmitoleic acid (16:1) and oleic acid (18:1),havereduced levels of polyunsaturated fatty acids in thechloroplast galactolipids.Seedlings of these mutantssubjected to chilling stress became chlorotic and hadhalf the chlorophyll content of wild-type.In addition,the number of thylakoid membranes in these mutantsdecreased and their chloroplasts were smaller.TheArabidopsis fad2 mutant,deficient in an endoplasmicreticulum (ER) localized x-6 desaturase,had significantlydecreased polyunsaturates in the extrachloroplastmembrane lipids.Long term culture of these mutantplants at low temperature (6\2C) eventually resulted intheir withering and death,but not for wild-type plants(Miquel et al 1993).Recent findings suggest that plantscapable of cold acclimation accumulate polyunsaturatesduring cold stress.Cold acclimating potato (Solanumcommersonii) was found to accumulate linoleic acid(18:2) in the membrane glycerolipids of the leaves,whereas commercial,non-acclimating potato (Solanumtuberosum) did not show this trait during cold stress