Molybdenum-induced alteration of fatty acids of thylakoid membranes contributed to low temperature tolerance in wheat

The fact that molybdenum (Mo) applications can alleviate low temperature stress (LTS) in plants has been widely reported, but the underlying mechanisms are not fully understood. The effects of Mo (0 and 0.15 mg kg^?1) on photosynthetic pigments, fatty acids and the chlorophyll–protein complex of wheat seedlings in pot culture were investigated at 0, 2, 4 and 6 days of LTS. Chlorophyll a and b, total chlorophyll and carotenoid contents were significantly enhanced by Mo application. The palmitic acid (C16:0) content and total saturated fatty acids (TSFA) were drastically decreased in wheat cultivar 97003 at 2 and 4 days of LTS and in wheat cultivar 97014 at 2 days of LTS. The linolenic acid (C18:3) content and total unsaturated fatty acids (TUSFA) were significantly increased in both cultivars at 2 and 4 days of LTS. The palmitoleic acid (C16:1) content was also drastically increased in cultivar 97003 at 2 days of LTS, suggesting that Mo induced a greater production of unsaturated fatty acids or the conversion of TSFA to TUSFA. The ratio of unsaturated to saturated fatty acids and the index of unsaturated fatty acids in the thylakoid membranes were enhanced with supplemental Mo, suggesting that Mo might improve the degree of unsaturation. However, no significant differences were observed in the chlorophyll–protein complexes between the +Mo and ?Mo treatments. These results indicated that the alteration of fatty acids induced by Mo application in the thylakoid membranes of wheat contributed to LTS tolerance.