1. Introduction
It is currently well known that phytohormones are involved in
the regulation of numerous physiological processes including
seed dormancy, plant development, and responses to biotic
and abiotic stresses in many higher plants. Under drought
conditions, the induction of ABA biosynthesis initiates the
signaling pathways within plant tissues, leading to numerous
molecular and cellular responses, such as the expression
of stress related genes and stomatal closure [1–4]. In this
regard, ABA plays a key role in root-to-shoot signaling under
drought inducing adaptive responses [3, 5, 6]. In general,
endogenous ABA increased under water deficit and was
reestablished to normal levels immediately after stress release