Effects of molybdenum on Endogenous Hormone Contents in winter wheat under low temperature stress

Molybdenum (Mo) is an essential element for higher plants. Recent research indicated that Mo application enhanced cold-resistance of winter wheat. In order to improve our understanding of the mechanisms of cold resistance enhanced by molybdenum application in winter wheat, liquid nutrient culture experiments were conducted to investigate the effects of molybdenum on endogenesis hormone in winter wheat (Mo efficient cv. 97003 and Mo inefficient cv. 97014) under low temperature stress. The results showed that Mo application increased the AO activities, the contents of abscisic acid (ABA) and indole-3-acetic acid (IAA) in the leaves of +Mo winter wheat under low temperature stress. No significant difference in the contents of GA3 and Z was detected between -Mo and +Mo winter wheat at the earlier stage of low temperature stress, whereas the contents of gibberellin (GA3) increased significantly, and zeatin (Z) decreased significantly in the leaves of +Mo winter wheat at the later stage of low temperature stress. Mo-deficiency also induced the drastic decrease of the ABA/GA in the leaves of winter wheat under low temperature stress. These results indicated that Mo regulated the ABA and IAA biosynthesis via AO in winter wheat and the response of ABA and IAA to Mo deficiency was prior to that of GA3 and ZT. The dramatic decrease in ABA and IAA levels in Mo deficient winter wheat may affect the homeostasis of endogenous hormones and Mo regulated cold resistance via the levels and balance of endogenous hormone in winter wheat