Rapid bench dehydration assay to assess ABA biosynthetic capacity
A method was developed to test for the capacity of leaves to rapidly synthesize ABA, relying on the well described effect of bench dehydration being able to induce ABA biosynthesis in leaves (Wright & Hiron, 1969). Branches were excised from individuals of each species at cardinal timepoints prior to water stress imposition and 10 d after peak ABA levels. To test whether tissues were capable of ABA biosynthesis branches were excised under water and rehydrated overnight, the following morning branches were dehydrated on a bench for 12 h inC. rhomboidea and 7 h in U. californica . Samples from the drying branches were collected periodically in U. californica or every 3 h in C. rhomboidea , to determine Ψl and foliage ABA and ABA-GE levels. Laboratory environmental data was logged to ensure a constant VPD (2.1 kPa) was maintained during the experiment.