ABA Regulation of Plant Responses to Drought and Salt Stresses - Abscisic Acid: Metabolism, Transport and Signaling - page 305

Chapter 16
ABA Regulation of Plant Responses
to Drought and Salt Stresses

Yun Ma and Feng Qin

Abstract The phytohormone abscisic acid (ABA) plays an essential role in the
abiotic stress response and tolerance of plants, especially during water-related
stresses. Thus, ABA is also known as a plant stress hormone. In response to
drought and/or salinity stresses, the expression of many ABA-responsive genes
is16.1 induced. Several transcription factors and their corresponding DNA target
sequences have been identified to control this biological response on the molecu-
lar level. Drought stress can directly induce ABA biosynthesis, transportation,
and release from its storage form. The activity of ion channels, located on the
guard cell membrane, is modulated by drought and/or salinity stresses to regu-
late stomata movement, which can be simulated by treatment with ABA. In this
chapter, we focus on the ABA regulation of drought and salt responses in plants,
examining gene expression, stress signaling, and ion homeostasis under these
stresses.

Keywords Drought stress · Salt stress · ABA · Plant responses

16.1 Introduction

Drought and salt stresses are two major environmental constrains threatening plant
growth and distribution. More than 10 % of the arable land has suffered from
drought and salinity, resulting in more than 50 % crop losses worldwide (Bray
et al. 2000 ; Roychoudhury et al. 2013 ). Dry soil during a drought causes photo-
synthetic decline, which affects nutrient availability. Salinity can result in physi-
ological drought and ion toxicity (Zhu 2002 ). Most of the high salinity-inducible