17 research outputs found
Salicylic acid and methyl jasmonate enhance drought tolerance in chamomile plants
Introduction: The dried flowers of chamomile contain many terpenoids and flavonoids contributing to its medicinal properties. Salicylic acid (SA) and methyl jasmonate (MeJA) have antioxidant properties and function as direct radical scavengers. Two Matricaria chamomilla cultivars (Bodgold and Hungary breed seeds) were used in this study to investigate the effects of exogenous application of SA and MeJA on protection against drought stress as well as on changes of malone dialdehyde (MDA) and electrolyte leakage index (ELI), and the fluctuation of proline and soluble sugars content in the leaves under drought stress. Methods: The experiment was conducted in a factorial design based on randomized complete blocks with three replicates. Chamomile plants were treated by two levels of drought stress as well as two different levels of MeJA (i.e., 0.0 and 100 μM) and SA (i.e., 0.0 and 0.5 mM) solutions. Results: There was a dramatic drought induced increase in the MDA content (128) and ELI (49) in the leaves. Deleterious effect of drought stress was more severe in untreated plants than in treated ones. Treatments with SA and MeJA significantly improved drought tolerance in chamomile plants. These treatments effectively maintained membrane integrity, thereby retarding electrolyte leakage and membrane lipid peroxidation (MDA). Treatments with SA and MeJA were also effective in enhancing the antioxidant concentrations of proline and soluble sugars. Conclusion: The production of these antioxidants could have been part of a defence system against drought damage, reducing MDA and ELI and maintaining membrane stability.</p
The effect of drought stress and super absorbent polymer (A200) on agronomical traits of sunflower (Helianthus annuus L.) under field condition
In many areas of Iran, the
reproductive growth stage of sunflower is
exposed to the drought stress. Therefore, the
investigation of irrigation management in
the farm was necessary for increasing
irrigation efficiency and decreasing water
loss. The objective of the present study was
to investigate the effect of different amounts
of super absorbent polymer (A200) and
levels of drought stress on morphological
characteristics, such as: head diameter, stem
diameter, plant height, 100-seed weight,
seed yield and physiological characteristics,
such as: relative water content (RWC),
chlorophyll concentration of sunflower (cv.
Master) under farm conditions. The
experiment was carried out as a split plot
based on randomized complete block design
with three replicates. Three irrigation levels
(irrigation after 6, 10 and 14 days) and five
amounts of super absorbent polymer (0, 75,
150, 225 and 300 kg/ha) were set as main
and sub-factors, respectively. Polymer was
added at the fourteen leaf stage of sunflower
to soil in deepness of root development. At
this same stage, drought stress was applied.
Polynomial models of each traits based on
the ANOVA were fitted. The results
indicated that drought stress has decreased
significantly all the measured traits. In this
study, seed yield has shown a significant
decrease. After 6 days, irrigation has
resulted in higher yields than other irrigation
intervals. The highest seed yield was related
to 300 kg/ha polymer application and the
lowest one was related to irrigation after 14
days with no application of polymer.
Regarding the limitation of water resources,
super absorbent polymer could be a useful
strategy for the sustainability of yield under
drought stress in sunflower
Response of proline, soluble sugars and antioxidant enzymes in wheat (Triticum aestivum L.) to different irrigation regimes in greenhouse condition
To evaluate the response of
proline and soluble sugars content, catalase
(CAT) and ascorbate peroxidase (APX)
activity in wheat leaves to different
irrigation regimes at two growth stages, a
greenhouse factorial experiment was
conducted in a completely randomized
design (CRD) with three replications. The
factors consisted of four different irrigation
regimes as 100% (I0), 75% (I1), 50% (I2) and
25% (I3) of field capacity and growth stages:
50% emergence to booting stage (GS1) and
booting stage to physiological maturity
(GS2). Fresh leaf tissues were used to
determine proline and soluble sugars
content, CAT and APX activity. According
to the results, irrigation regimes had
significant effect on proline content, soluble
sugars and APX activity, but no significant
differences were detected among irrigation
regimes for catalase (CAT) activity. Limited
irrigation increased proline concentration
and total soluble sugars in leaves. None of
studied traits were affected by growth
stages. Interaction between irrigation
regimes and growth stages was not
significant for all studied traits. Results
indicated that the highest proline content (12
μmol/g DW), total soluble sugars (49 mg/g
DW) and APX activity (42 μmol min-1 g-1
FW) were related to irrigation at 25% of
field capacity (I3). It was concluded that
proline and soluble sugar levels were
increased in wheat leaves under deficit
irrigation regimes
Effect of drought stress and polymer on osmotic adjustment and photosynthetic pigments of sunflower
Water stress affects plant
growth and crop productivity in the vast
semi-arid and arid regions of Iran. The
present study was aimed at investigating the
effect of drought stress and super absorbent
polymer (SAP) on the osmotic adjustment
and carotenoid content of sunflower (cv.
Master) under field condition. The
experiment was carried out as a split plot
based on randomized complete block design
with three replications. Three irrigation
levels (irrigation after 6, 10 and 14 days)
and five amount of super absorbent polymer
(SAP) (0, 75, 150, 225, 300 kg/ha) were set
as main and sub factors, respectively.
Polymer was added in fourteen leaves stage
of sunflower to soil in deepness of roots
development (by mixing with soil) and at
this same stage drought stress was
applied.The results showed that effect of
different rates of super absorbent polymer
and water stress in all traits were significant
(P<0.001) as well as their interactive effect
of two mentioned factors were significant (P
<0.001).Drought stress significantly
increased carotenoid content. Drought stress
caused an increase in the concentration of
soluble sugar and proline content in the
leaves of sunflower. These results indicated
that lowest amount in proline and soluble
sugars accumulation were achieved at 300
kg ha-1 polymer compared with the control
(without polymer) in all rates of water even
under drought stress conditions.Our results
showed that SAP can absorb and retain
extremely large amounts of water, so
protects the plants against drought
Seed reserve utilization and seedling growth of treated seeds of mountain rye (Secale montanum) as affected by drought stress
The environmental stress
such as, drought are serious obstacles for
field crops in further areas of the world,
especially in arid and semiarid regions. In
order to investigate drought stress on seed
reserve utilization and seedling growth of
treated seeds of mountain rye (Secale
montanum), an experiment was carried out.
Factorial experiment was carried out in
completely randomized design with three
replications. The first factor was the seed
treatments (unpriming, hydropriming and
osmopriming) and the second factor was
drought stress. To create drought stress,
polyetylenglycol 6000 (PEG 6000) in
osmotic levels at 0 (as control), -0.4, -0.8, -
1.2 and -1.6 MPa were used. The results
indicated that for these traits: germination
percentage (GP), timson index (TI), energy
of germination (EG), weight of utilized
(mobilized) seed (WMSR), seed reserve
utilization efficiency (SRUE), seedling dry
weight (SLDW), and seed reserve depletion
percentage (SRDP), was a significant
treatment × drought interaction. Thus
hydropriming and osmopriming
improvement study traits in Secale
montanum under drought stress. While in
higher osmotic pressure the highest seed
reserve utilization were obtained from
osmopriming
Effect of Water Deficit Stress and Foliar Application of Salicylic Acid on Antioxidants Enzymes Activity in Leaves of Thymus Daenensis Subsp. Lancifolius
In order to study the effects
of water deficit stress and foliar application
of salicylic acid (SA) on the activity of five
antioxidant enzymes (catalase - CAT; EC
1.11.1.6, ascorbate peroxidase - APX; EC
1.11.1.11, glutathione reductase - GR; EC
1.6.4.2, peroxidase - POD; EC 1.11.1.7 and
polyphenol oxidase - PPO; 1.14.18.1) of
Thymus daenensis (subsp. lancifolius), an
experiment was conducted in factorial based
on completely randomized design with three
replicates, during 2013. Drought treated
seedlings showed elevated levels of reactive
oxygen species (ROSs), with a concomitant
increase in the activities of the enzymes
CAT, APX, GR, POD and PPO, compared
to controls. Under medium water deficit,
APX and PPO activities significantly
increased by higher SA concentration
(2 mM), but under control and sever water
deficit conditions, there was no significant
difference between 1 mM and 2 mM
concentrations regarding APX and PPO
activity. Under all levels of available water,
increase in SA concentration from 0.1 mM
to1 mM induced significant increase in GR
activity. The maximum amount of GR
(under medium water deficit condition)
achieved from 1mM of SA. While the
maximum amounts of APX, PPO (under
medium water deficit condition), CAT and
POD (under sever water deficit condition)
achieved from 2 mM of SA. In total, our
results suggest that application of SA (as a
trigger of signal cascade) could be
advantageous against water deficit stress,
and could protect thyme plants in mentioned
conditions
Effect of water deficit stress and foliar application of salicylic acid on antioxidants enzymes activity in leaves of Thymus daenensis subsp. Lancifolius
In order to study the effects
of water deficit stress and foliar application
of salicylic acid (SA) on the activity of five
antioxidant enzymes (catalase - CAT; EC
1.11.1.6, ascorbate peroxidase - APX; EC
1.11.1.11, glutathione reductase - GR; EC
1.6.4.2, peroxidase - POD; EC 1.11.1.7 and
polyphenol oxidase - PPO; 1.14.18.1) of
Thymus daenensis (subsp. lancifolius), an
experiment was conducted in factorial based
on completely randomized design with three
replicates, during 2013. Drought treated
seedlings showed elevated levels of reactive
oxygen species (ROSs), with a concomitant
increase in the activities of the enzymes
CAT, APX, GR, POD and PPO, compared
to controls. Under medium water deficit,
APX and PPO activities significantly
increased by higher SA concentration
(2 mM), but under control and sever water
deficit conditions, there was no significant
difference between 1 mM and 2 mM
concentrations regarding APX and PPO
activity. Under all levels of available water,
increase in SA concentration from 0.1 mM
to1 mM induced significant increase in GR
activity. The maximum amount of GR
(under medium water deficit condition)
achieved from 1mM of SA. While the
maximum amounts of APX, PPO (under
medium water deficit condition), CAT and
POD (under sever water deficit condition)
achieved from 2 mM of SA. In total, our
results suggest that application of SA (as a
trigger of signal cascade) could be
advantageous against water deficit stress,
and could protect thyme plants in mentioned
conditions