Lipid Labeling in Normal and Nitrogen-Deficient Squash (Cucurbita maxima) Leaves |
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Authors: | D. DALGARN D. HUBER D. W. NEWMAN |
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Affiliation: | Botany Department, Miami University, Oxford, Ohio 45056 U.S.A. |
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Abstract: | Squash (Cucurbita maxima Duchesne) plants were grown on normal and on nitrogen-deficient nutrients. The degrees of label incorporation into chloroplast lipids as well as non-chloroplast lipids were determined. Nitrogen-deficient tissues contain less chlorophyll, have a decreased chlorophyll a/b ratio, incorporate more label into phosphatidyl choline and phosphatidyl ethanolamine than into the chloroplast lipids such as mono- and digalactosyl diglycerides, have a reduced capacity to incorporate the hexose moieties into the glycolipids but normal capacity to incorporate bases into the phospholipids of non-chloroplast constituents, and have a normal level of total fatty acids even though the level of linolenate is decreased. All of this would suggest that the most evident changes in membrane lipid constituents during nitrogen-deficiency occur as changes in the chloroplast lipid constituents as opposed to the non-chloroplast lipid constituents. |
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