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Ascorbic acid mitigation of water stress-inhibition of root growth in association with oxidative defense in tall fescue (Festuca arundinacea Schreb.).

Xu Y, Xu Q, Huang B - Front Plant Sci (2015)

Bottom Line: In addition, free ascorbate and total ascorbate content were significantly higher in roots treated with ASA under water stress than those without ASA treatment.The enzymatic activities for ROS scavenging-related genes were not significantly altered by ASA treatment under water stress, while transcript abundances of genes encoding superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase showed significant decreases in the root elongation zone and significant increases in the root maturation zone treated with ASA under water stress.The results suggested that exogenous treatment of roots with ASA enhanced root elongation under water stress, which could be attributed by increasing non-enzymatic antioxidant production, suppressing ROS toxicity and up-regulating gene expression of cell-wall loosening proteins controlling cell expansion.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Biology and Pathology, Rutgers University New Brunswick, NJ, USA.

ABSTRACT
Root growth inhibition by water stress may be related to oxidative damages. The objectives of this study were to determine whether exogenous application of ascorbic acid (ASA) could mitigate root growth decline due to water stress and whether ASA effects on root growth could be regulated through activating non-enzymatic or enzymatic antioxidant systems in perennial grass species. Tall fescue (Festuca arundinacea Schreb. cv. "K-31") plants were grown in nutrient solution, and polyethylene glycol (PEG)-8000 was added into the solution to induce water stress. For exogenous ASA treatment, ASA (5 mM) was added into the solution with or without PEG-8000. Plants treated with ASA under water stress showed significantly increased root growth rate, and those roots had significantly lower content of reactive oxygen species (ROS) (H2O2 and O[Formula: see text] content) than those without ASA treatment. Malondialdehyde content in root tips treated with ASA under water stress was also significantly reduced compared with those under water stress alone. In addition, free ascorbate and total ascorbate content were significantly higher in roots treated with ASA under water stress than those without ASA treatment. The enzymatic activities for ROS scavenging-related genes were not significantly altered by ASA treatment under water stress, while transcript abundances of genes encoding superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase showed significant decreases in the root elongation zone and significant increases in the root maturation zone treated with ASA under water stress. Transcripts of genes for expansins and xyloglucan endotransglycosylases showed increased abundances in ASA-treated root maturation zone under water stress, indicating that ASA could accelerated cell wall loosening and cell expansion. The results suggested that exogenous treatment of roots with ASA enhanced root elongation under water stress, which could be attributed by increasing non-enzymatic antioxidant production, suppressing ROS toxicity and up-regulating gene expression of cell-wall loosening proteins controlling cell expansion.

No MeSH data available.


Related in: MedlinePlus

Histochemical staining of tall fescue roots for visual localization of super oxide (O) (A for non-stress control, B for water stress, and C for water stress with ASA treatment) and hydrogen peroxide (H2O2) (D for non-stress control, E for water stress, and F for water stress with ASA treatment). Bar represents for 100 μm.
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Figure 4: Histochemical staining of tall fescue roots for visual localization of super oxide (O) (A for non-stress control, B for water stress, and C for water stress with ASA treatment) and hydrogen peroxide (H2O2) (D for non-stress control, E for water stress, and F for water stress with ASA treatment). Bar represents for 100 μm.

Mentions: The production of O and H2O2 was examined in both root elongation e and maturation zones using quantitative measurement (Figure 3) and histochemical staining (Figure 4) to determine level of oxidative stress induced by water stress and effectiveness of ASA treatment for oxidative scavenging in roots. Water stress significantly increased both O (1.68-fold) and H2O2 content (1.25-fold) in the root elongation zone, while it did not alter either O or H2O2 production in the maturation zone (Figures 3A,B). The histochemical staining also showed increased staining density for both O and H2O2 in the root elongation zone under water stress (Figures 4B,E). The ASA treatment caused significantly lower O (1.32-fold) and H2O2 (1.13-fold) content in the elongation zone than those without ASA treatment under water stress, but had not effects on either O or H2O2 in the maturation zone (Figures 3A,B). The histochemical staining pattern for ASA-treated roots also have less staining density for both O and H2O2 in the elongation zone, indicating ASA-mitigation of oxidative stress in the root elongation zone (Figures 4C,F).


Ascorbic acid mitigation of water stress-inhibition of root growth in association with oxidative defense in tall fescue (Festuca arundinacea Schreb.).

Xu Y, Xu Q, Huang B - Front Plant Sci (2015)

Histochemical staining of tall fescue roots for visual localization of super oxide (O) (A for non-stress control, B for water stress, and C for water stress with ASA treatment) and hydrogen peroxide (H2O2) (D for non-stress control, E for water stress, and F for water stress with ASA treatment). Bar represents for 100 μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591509&req=5

Figure 4: Histochemical staining of tall fescue roots for visual localization of super oxide (O) (A for non-stress control, B for water stress, and C for water stress with ASA treatment) and hydrogen peroxide (H2O2) (D for non-stress control, E for water stress, and F for water stress with ASA treatment). Bar represents for 100 μm.
Mentions: The production of O and H2O2 was examined in both root elongation e and maturation zones using quantitative measurement (Figure 3) and histochemical staining (Figure 4) to determine level of oxidative stress induced by water stress and effectiveness of ASA treatment for oxidative scavenging in roots. Water stress significantly increased both O (1.68-fold) and H2O2 content (1.25-fold) in the root elongation zone, while it did not alter either O or H2O2 production in the maturation zone (Figures 3A,B). The histochemical staining also showed increased staining density for both O and H2O2 in the root elongation zone under water stress (Figures 4B,E). The ASA treatment caused significantly lower O (1.32-fold) and H2O2 (1.13-fold) content in the elongation zone than those without ASA treatment under water stress, but had not effects on either O or H2O2 in the maturation zone (Figures 3A,B). The histochemical staining pattern for ASA-treated roots also have less staining density for both O and H2O2 in the elongation zone, indicating ASA-mitigation of oxidative stress in the root elongation zone (Figures 4C,F).

Bottom Line: In addition, free ascorbate and total ascorbate content were significantly higher in roots treated with ASA under water stress than those without ASA treatment.The enzymatic activities for ROS scavenging-related genes were not significantly altered by ASA treatment under water stress, while transcript abundances of genes encoding superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase showed significant decreases in the root elongation zone and significant increases in the root maturation zone treated with ASA under water stress.The results suggested that exogenous treatment of roots with ASA enhanced root elongation under water stress, which could be attributed by increasing non-enzymatic antioxidant production, suppressing ROS toxicity and up-regulating gene expression of cell-wall loosening proteins controlling cell expansion.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Biology and Pathology, Rutgers University New Brunswick, NJ, USA.

ABSTRACT
Root growth inhibition by water stress may be related to oxidative damages. The objectives of this study were to determine whether exogenous application of ascorbic acid (ASA) could mitigate root growth decline due to water stress and whether ASA effects on root growth could be regulated through activating non-enzymatic or enzymatic antioxidant systems in perennial grass species. Tall fescue (Festuca arundinacea Schreb. cv. "K-31") plants were grown in nutrient solution, and polyethylene glycol (PEG)-8000 was added into the solution to induce water stress. For exogenous ASA treatment, ASA (5 mM) was added into the solution with or without PEG-8000. Plants treated with ASA under water stress showed significantly increased root growth rate, and those roots had significantly lower content of reactive oxygen species (ROS) (H2O2 and O[Formula: see text] content) than those without ASA treatment. Malondialdehyde content in root tips treated with ASA under water stress was also significantly reduced compared with those under water stress alone. In addition, free ascorbate and total ascorbate content were significantly higher in roots treated with ASA under water stress than those without ASA treatment. The enzymatic activities for ROS scavenging-related genes were not significantly altered by ASA treatment under water stress, while transcript abundances of genes encoding superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase showed significant decreases in the root elongation zone and significant increases in the root maturation zone treated with ASA under water stress. Transcripts of genes for expansins and xyloglucan endotransglycosylases showed increased abundances in ASA-treated root maturation zone under water stress, indicating that ASA could accelerated cell wall loosening and cell expansion. The results suggested that exogenous treatment of roots with ASA enhanced root elongation under water stress, which could be attributed by increasing non-enzymatic antioxidant production, suppressing ROS toxicity and up-regulating gene expression of cell-wall loosening proteins controlling cell expansion.

No MeSH data available.


Related in: MedlinePlus