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EDU and ozone protection: Foliar glycerolipids and steryl lipids in snapbean exposed to O 3
Author(s) -
Whitaker Bruce D.,
Lee Edward H.,
Rowland Randy A.
Publication year - 1990
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1990.tb04409.x
Subject(s) - stigmasterol , phaseolus , chlorophyll , chemistry , botany , phospholipid , biology , horticulture , biochemistry , chromatography , membrane
Effects of the antiozonant EDU, N‐[2‐(2‐oxo‐1‐imidazolidinyl) ethyl]‐N'‐phenylurea, on the content and composition of foliar lipids in snapbean ( Phaseolus vulgaris L. cv. Bush Blue Lake 290) before and after a single, acute ozone (O 3 ) exposure were assessed. Pretreatment with EDU conferred protection against O 3 ‐induced necrosis and losses of glycerolipids and chlorophyll. Systemic treatment of snapbean plants with EDU did not significantly alter membrane lipids in the first trifoliate leaf. Leaves of untreated controls had lost ca 50% of both galacto‐ (GL) and phospholipids (PL) by the end of a 3 h exposure to 0.4 μl l −1 O 3 . A decline in the ratio of mono‐ to di‐galactosyldiacylglycerol (MGDG/DGDG) was associated with the loss of GL, and a decline in the ratio of linoleic to linolenic acid (18:2/18:3) was associated with the loss of PL in untreated controls. EDU‐treated plants showed no significant loss of foliar GL and PL. The MGDG/DGDG ratio declined only slightly, and the 18:2/18:3 ratio in PL increased during O 3 exposure of EDU‐treated seedlings. The level of total membrane sterols, including free sterols (FS), acylated steryl glycosides (ASG) and steryl glycosides (SG), did not change during O 3 exposure of either treated or untreated plants. However, in the controls the proportions of ASG and SG increased at the expense of FS, and the ratio of stigmasterol/sitolsterol increased in FS and SG. In EDU‐treated plants, a relatively small increase in SG was offset by a decrease in FS, and there was no change in the stigmasterol/sitosterol ratio in ASG, SG or FS. The results indicate that EDU may confer tolerance to O 3 through induction of enzyme systems involved in the elimination of activated oxygen species and free radicals.