Agriculture Reference
In-Depth Information
Suppressed
growth
Protein denaturation &
membrane destabilization
Decrease in
photosynthesis and
pigmentation
Cytotoxicity
Stomatal closure
senescence
wilting
Necrosis
Chlorosis
Mineral/toxic ions
accumulation
ROS accumulation
Osmotic stress,
Physiological
drought
Cell
death
Nutrient unavailability,
Competitive exclusion
of nutrients
lonic
imbalance
Fig. 11.1
An overview of stress effects on the plant. Effects include a combinatorial picture of salt
and metal stress (ionic imbalance) and drought stress (osmotic stress) on physiological and
metabolic aspects of plants focusing mainly on leaves and root-associated processes which
ultimately lead to inhibition in growth
Drought stress can be defined as low water or moisture content in soil, not enough to
fulfill the plant requirements. When the water loss occurs due to metabolic pro-
cesses and transpiration exceeds the water availability for absorption or when water
content of plant gets low enough to interfere with normal plant processes, water
deficit/stress is created. It can also result from reduced moisture of soil, due to less
rainfall or supplemental irrigation. Water stress has been found as an important
factor affecting deleteriously various stages/metabolic processes of plants
(Upadhyay and Panda
2013
). For example, water stress reduces the water potential
of plant cell and thus enhances the solute concentration, which further hinders cell
enlargement, stem proliferation, and root elongation, thereby hampering the plant
growth (Akinci and Losel
2012
). However, when plants are growing under stressed
situation, it exhibits visible symptoms. As an example, “wilting” is the condition of
plants where the non-wooden parts of the plants become nonrigid due to low turgor
pressure and is one of the most common symptoms of water stress (Correia
et al.
2001
; Cabuslay et al.
2002
). Also, water stress may cause stomata closure.
Accumulation of plant hormone, for instance, abscisic acid (ABA), is responsible
for the stomatal closure (Socias et al.
1997
). This further reduces gaseous exchange,
