Fig. 7.

Model summarizing the role of JA and ABA in dormancy release by cold stratification in wheat. Stratification stimulates rapid changes in two hormones known to regulate dormancy. First, there is a decrease in ABA content, independent of JA (dotted line), which is driven by the repression of TaNCED1 and TaNCED2. Secondly, there is a cold-induced increase in JA content that also decreases ABA by repressing the NCED genes. The increase in JA is driven by the cold-induced expression of TaAOS and TaAOC. Blockage of JA biosynthesis using ASA results in high ABA content; thus, the maintenance of low ABA after stratification is dependent on JA production. In cereals, NCED1 is a common key target of environmental factors (cold, heat, light, and after-ripening) that affect germination.