Agriculture Reference
In-Depth Information
(Graziano et al.
2002
). Recently, administration of SNP on the leaves of peanut
(
Arachis hypogaea
Linn) iron-deficient plants enhanced plant growth and decreased
leaf interveinal chlorosis (Zhang et al.
2012
). Moreover, administration of NO
donor increased the activities of root Fe III reductase and antioxidant enzymes
and reduced malondialdehyde content (Zhang et al.
2012
). Overall, NO might act as
a signaling molecule in the regulation of physiological adaptive change in plant
growth under iron-deficient conditions.
Recently, the relation between AtHO1 (encodes heme oxygenase-1 in
Arabidopsis
) on the catalysis of the cleavage of heme to biliverdin yielding iron
and carbon monoxide (CO) was examined (Li et al.
2013
). Indeed, NO is known to
regulate iron homeostasis in plants. AtHO1-overexpressing plants generated high
concentrations of NO; however, knockdown of AtHO1 expression decreased plant
levels of NO. The NO scavenger 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylini-
dazoline-1-oxyl-3-oxide (cPTIO) decreased AtHO1-induced ferric-chelate reduc-
tase (FCR) activity. In the case of iron-sufficient and iron-deficient conditions,
application of SNP induced FCR activity in the
hy1
plants. The authors suggested
that AtHO1 was involved in iron homeostasis in an NO-dependent manner
(Li et al.
2013
).
Recently, a novel insight into the effect of application of different concentrations
of SNP on the nitrosative status and nitrate metabolism of mature and senescing
Medicago truncatula
plants showed that higher concentrations of SNP resulted in
increased NO content, cellular damage levels, and augmentation of ROS concen-
tration. Senescing in this plant demonstrated greater sensitivity to SNP-induced
oxidative and nitrosative damage probably to iron deficiency. This fact suggests a
developmental stage-dependent suppression in the plant
s ability to survive with
free oxygen and nitrogen radicals (Sivitz et al.
2012
; Antoniou et al.
2013
).
'
9.2.3 Exogenous NO Donors in Plants Tolerance to Salinity
Some interesting reports describing the beneficial effects of administration of NO
donors on plants exposed to salinity stress were recently published. Corpas
et al. (
2011
) reported the stimulation in the expression of plasma membrane H
+
-
ATPase of calluses of reed under the addition of high NaCl concentration and
treatment with SNP. The authors observed an increase in the K
+
and Na
+
ratio, and
the authors proposed that NO acts as a signal-inducing salt resistance (Corpas
et al.
2011
). Moreover, application of SNP enhanced seed germination in wheat
and protected plant against mitochondrial oxidative damage caused by high salin-
ity. The addition of NO donor also decreased the release rates of malondialdehyde
(MDA), hydrogen peroxide, and superoxide anions by mitochondria (Zheng
et al.
2009
). A recent paper reported an increase in the Na
+
secretion per leaf of
Limonium bicolor
treated with high NaCl concentration combined with SNP for
20 days (Ding
2012
).
