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.