Changes In Ascorbic Acid Content Research Articles

Development of hyaluronic acid based polysaccharide-protein composite edible coatings for preservation of strawberry fruit

With the growing demand for extending the shelf-life of perishable goods such as fruits and vegetables, there is continued interest towards the development of edible coatings derived from natural sources. To avoid rapid dissolution, water insoluble polysaccharide such as chitosan has been widely explored. In this work, we developed robust hyaluronic acid-based edible polysaccharide-protein coatings by combining it (hyaluronic acid) with chitosan and gelatin to introduce additional antioxidant properties. This work is the first example of using hyaluronic acid in edible coatings for fruit preservation. The effect of developed edible composite coatings on the quality of coated strawberries was investigated over a 15 day storage period with 3-day examination intervals. The obtained results revealed hyaluronic acid dose-dependent improvement in intrinsic properties of coated strawberries including weight loss, pH, titratable acidity (TA) and total solids content (TSS). Furthermore, the inclusion of hyaluronic acid significantly enhanced the antioxidant properties of developed edible coatings as measured using total phenolic content, change in ascorbic acid content and DPPH assay prolonging the shelf-life of coated strawberries.

Combined antibacterial effect of 460nm light-emitting diode illumination and chitosan against Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes on fresh-cut melon, and the impact of combined treatment on fruit quality.

This study evaluated the combined antibacterial effect of 460nm LED illumination and chitosan on Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes on fresh-cut melon surface and its impact on the quality of melon at a total dose of 2.4kJ/cm2 at 4 and 10 °C. Results showed that the antibacterial effect of LED illumination in combination with chitosan (0.5 and 1.0%) was much better than that of LED illumination alone, showing their synergistic effect. Among the pathogens, L. monocytogenes was the most susceptible pathogen to LED illumination. Although the color of melons became paler after LED illumination, there was little to no change in ascorbic acid content, total flavonoid content, or antioxidant capacity of the illuminated fruits compared with non-illuminated fruits. Thus, these results suggest that chitosan-mediated 460nm LED illumination could be applied to inactivate foodborne pathogens on fresh-cut melons during storage at food establishments.

Degradation kinetics of bioactive compounds in dried mistletoe leaves during storage

This work evaluated the effect of air atmosphere packaging and modified atmosphere packaging on the quality and nutritional compounds of dried mistletoe leaves during 4 months of storage at 4 and 25 °C temperatures. Mistletoe leaves packaged with modified atmosphere had improved nutritional qualities overall as compared to mistletoe leaves packaged with atmosphere air. At the end of the storage period, water activity values of all samples increased by 0.72%–3.38%. Before storage, the dried mistletoe leaves' total phenolic content was determined to be 301.73 ± 2.49 mg GAE/100 g dry matter. The total phenolic content of the samples decreased by 62.00%–71.96% after four months of storage. It was determined that the highest loss of total phenolic content was observed at room temperature (25 °C) and in the samples packaged with normal atmospheric air. Total antioxidant activity values in MAP2 samples decreased by 23.82% after four months when kept at low temperatures, but the loss was calculated to be 34.48% in cases where they were kept at room temperature. Ascorbic acid content losses in AP, MAP1, and MAP2 samples kept at room temperature were 21.48%, 15.90%, and 14.72%, respectively. In the samples stored at low temperatures, these loss rates were calculated as 16.62%, 13.05%, and 12.05%, respectively. No single model was satisfactory for describing changes in ascorbic acid content, which could not be determined in the samples stored at both 4 °C and 25 °C. The dried mistletoe leaves modified atmosphere packed and stored at low temperatures provided the highest bioactive compound retention.

Dynamic Changes in Ascorbic Acid Content during Fruit Development and Ripening of Actinidia latifolia (an Ascorbate-Rich Fruit Crop) and the Associated Molecular Mechanisms.

Actinidia latifolia is one of the very few kiwifruit genotypes with extremely high ascorbic acid (AsA) content. However, a transcriptome atlas of this species is lacking. The accumulation of AsA during fruit development and ripening and the associated molecular mechanisms are still poorly understood. Herein, dynamic changes in AsA content at six different stages of A. latifolia fruit development and ripening were determined. AsA content of A. latifolia fruit reached 1108.76 ± 35.26 mg 100 g−1 FW at full maturity. A high-quality, full-length (FL) transcriptome of A. latifolia was successfully constructed for the first time using third-generation sequencing technology. The transcriptome comprises 326,926 FL non-chimeric reads, 15,505 coding sequences, 2882 transcription factors, 18,797 simple sequence repeats, 3328 long noncoding RNAs, and 231 alternative splicing events. The genes involved in AsA biosynthesis and recycling pathways were identified and compared with those in different kiwifruit genotypes. The correlation between the AsA content and expression levels of key genes in AsA biosynthesis and recycling pathways was revealed. LncRNAs that participate in AsA-related gene expression regulation were also identified. Gene expression patterns in AsA biosynthesis and metabolism exhibited a trend similar to that of AsA accumulation. Overall, this study paves the way for genetic engineering to develop kiwifruits with super-high AsA content.

Effect of Ultrasound and Enzymatic Mash Treatment on Bioactive Compounds and Antioxidant Capacity of Black, Red and White Currant Juices

Ultrasound treatment is recognized as a potential technique for improvement in the nutritional values of fruit juices. This study was initiated with the objective of evaluating bioactive compounds and some important quality parameters of black (BC), red (RC) and white (WC) currant juices obtained from fruit mash preliminarily treated by enzymes combined with ultrasound. Individual and total phenolic content (TPC), anthocyanins, color parameters, ascorbic acid, antioxidant capacity (TEAC), juice yield, pH, titratable acidity, and soluble solids were investigated. Significant increases in the levels of TPC and antioxidant capacity of sonicated samples were observed. However, ultrasound treatment had no effect on individual phenolic compounds of juices. Sonication of mash before juice pressing did not cause any noticeable changes in ascorbic acid content. Only in the case of WC was an increase in content of vitamin C noticed. The color of juices obtained after treatment was similar to the control sample. It was demonstrated that enzymatic combined with ultrasound treatment of mash for different colored currant fruit did not have any dismissive effect and could even improve some parameters of the juice obtained.

Differentially expressed protein and gene analysis revealed the effects of temperature on changes in ascorbic acid metabolism in harvested tea leaves

Tea is an important non-alcoholic beverage worldwide. Tea quality is determined by numerous secondary metabolites in harvested tea leaves, including tea polyphenols, theanine, caffeine, and ascorbic acid (AsA). AsA metabolism in harvested tea leaves is affected by storage and transportation temperature. However, the molecular mechanisms underlying AsA metabolism in harvested tea leaves exposed to different storage and transportation temperature conditions remain unclear. Here we performed RP-HPLC to detect dynamic changes in AsA content in tea leaves subjected to high- (38 °C), low- (4 °C), or room-temperature (25 °C) treatments. The AsA distribution and levels in the treated tea leaves were analyzed using cytological–anatomical characterization methods. The differentially expressed CsAPX1 and CsDHAR2 proteins, which are involved in the AsA recycling pathway, were identified from the corresponding proteomic data using iTRAQ. We also analyzed the expression profiles of 18 genes involved in AsA metabolism, including CsAPX1 and CsDHAR2. AsA was mainly distributed in tea leaf mesophyll cells. High- and low-temperature treatments upregulated the CsAPX1 and CsDHAR2 proteins and induced CsAPX and CsDHAR2 gene expression. These results indicated that the CsAPX1 and CsDHAR2 proteins might have critical roles in AsA recycling in tea leaves. Our results provide a foundation for the in-depth investigation of AsA metabolism in tea leaves during storage and transportation, and they will promote better tea flavor in tea production.

Effect of nanocellulose/chitosan composite coatings on cucumber quality and shelf life

ABSTRACTNanocellulose/chitosan composite coatings are useful for their mechanical and barrier properties, biodegradability, and food safety applications. The aim of this study was to investigate the effects of 1% chitosan (CS) and 5% nanocellulose (NCC) composite coatings on cucumber. The influence on quality and antioxidant enzymes were investigated by immersing cucumbers in deionized water (CK), chitosan solution (CS), and nanocellulose/chitosan composite solution (NCC/CS), respectively, during a 14-day storage at 4° C. At the end of storage, weight loss of cucumbers in NCC/CS decreased to 8.4%, and firmness reduced by 20.3%. Chlorophyll degradation was noticeable in visual appearance and lowered by 25.5%, there was no marked change in ascorbic acid content. Total soluble solids decreased 0.78%. The enzymatic activities responsible for softening phenomena including catalase (CAT) and peroxidase (POD) activity fell 25.6% and 16.1%, respectively. Alterations were more apparent in CK cucumbers. The results confirm that the use of NCC/CS composite coatings might maintain quality and extend the shelf life of cucumbers.

Effect of l-ascorbic acid addition on quality, polyphenolic compounds and antioxidant capacity of cloudy apple juices

Polyphenols are one of the most important dietary antioxidants, and the apples, being a major source of polyphenolic compounds. There is increasing evidence that the consumption of fruit and their preserves, which are rich sources of vitamins and phenolics, is negatively associated with lung cancer and coronary heart disease. The influence of ascorbic acid addition on the quality, polyphenolic profile and antioxidant capacity in 14 selected varieties of apple juices during the 3 years of study was examined. Evaluation of changes of ascorbic acid content allowed to demonstrate the differences in susceptibility of apples on the enzymatic oxidation. The study shows that the variations of the least susceptible to oxidation of ascorbic acid are ‘Shampion’ and ‘Topaz’, and to a lesser extent, ‘Szara Reneta’, ‘Arlet’ and ‘Jonafree’ apples. A total of 17 kinds of polyphenolic compounds including catechins, procyanidins, hydroxycinnamates, flavonols, anthocyanins and dihydrochalcones were identified in apple tissues by HPLC with DAD analysis and after phloroglucinolysis and LC–MS. During the 3 years of study, the addition of ascorbic acid positively affects on the polyphenol compounds and antioxidant capacity (DPPH, ABTS and FRAP), increasing their content in the analyzed samples by 65 and 433, 328 and 300 %, respectively. The correlation coefficient between DPPH, ABTS and FRAP antioxidant capacity and ascorbic acid was 0.71, 0.71 and 0.72, respectively.

Arabidopsis CSN5B Interacts with VTC1 and Modulates Ascorbic Acid Synthesis

Light regulates ascorbic acid (AsA) synthesis, which increases in the light, presumably reflecting a need for antioxidants to detoxify reactive molecules produced during photosynthesis. Here, we examine this regulation in Arabidopsis thaliana and find that alterations in the protein levels of the AsA biosynthetic enzyme GDP-Man pyrophosphorylase (VTC1) are associated with changes in AsA contents in light and darkness. To find regulatory factors involved in AsA synthesis, we identified VTC1-interacting proteins by yeast two-hybrid screening of a cDNA library from etiolated seedlings. This screen identified the photomorphogenic factor COP9 signalosome subunit 5B (CSN5B), which interacted with the N terminus of VTC1 in yeast and plants. Gel filtration profiling showed that VTC1-CSN5B also associated with the COP9 signalosome complex, and this interaction promotes ubiquitination-dependent VTC1 degradation through the 26S proteasome pathway. Consistent with this, csn5b mutants showed very high AsA levels in both light and darkness. Also, a double mutant of csn5b with the partial loss-of-function mutant vtc1-1 contained AsA levels between those of vtc1-1 and csn5b, showing that CSN5B modulates AsA synthesis by affecting VTC1. In addition, the csn5b mutant showed higher tolerance to salt, indicating that CSN5B regulation of AsA synthesis affects the response to salt stress. Together, our data reveal a regulatory role of CSN5B in light-dark regulation of AsA synthesis.

L-ascorbic Acid: a multifunctional molecule supporting plant growth and development.

L-Ascorbic acid (vitamin C) is as essential to plants as it is to animals. Ascorbic acid functions as a major redox buffer and as a cofactor for enzymes involved in regulating photosynthesis, hormone biosynthesis, and regenerating other antioxidants. Ascorbic acid regulates cell division and growth and is involved in signal transduction. In contrast to the single pathway responsible for ascorbic acid biosynthesis in animals, plants use multiple pathways to synthesize ascorbic acid, perhaps reflecting the importance of this molecule to plant health. Given the importance of ascorbic acid to human nutrition, several technologies have been developed to increase the ascorbic acid content of plants through the manipulation of biosynthetic or recycling pathways. This paper provides an overview of these approaches as well as the consequences that changes in ascorbic acid content have on plant growth and function. Discussed is the capacity of plants to tolerate changes in ascorbic acid content. The many functions that ascorbic acid serves in plants, however, will require highly targeted approaches to improve their nutritional quality without compromising their health.

Senescence Marker Protein-30/Gluconolactonase Expression in the Mouse Ovary during Gestation

Senescence marker protein-30 (SMP30) was first described as a physiologic entity that decreases in the rat liver and kidney with aging. Previously, we established that SMP30 is the lactone-hydrolyzing enzyme gluconolactonase (GNL), which is involved in ascorbic acid (AA) biosynthesis. In the present study, we found SMP30/GNL mRNA expressed in the mouse ovary. To ascertain the reason for ovarian SMP30/GNL expression, we examined mice during gestation. SMP30/GNL mRNA expression was evident at the start of gestation, increased for the next eight days then decreased rapidly. Moreover, L-gulono-γ-lactone oxidase (Gulo) mRNA, which catalyzes the last step of AA, was found in the ovaries of these mice. The variations of these genes' expression showed an inverse pattern to that of Cyp19a1 (aromatase) mRNA expression. Therefore, the SMP30/GNL and Gulo mRNA expression might be regulated by estrogen levels in the ovary. Since the presence of both SMP30/GNL and Gulo mRNAs could indicate that AA synthesis occurs in the ovary, we quantified AA levels in mouse ovaries during gestation. However, no correlation was found between changes of AA content and SMP30/GNL or Gulo mRNAs expression at this site. Moreover, we compared the changes of AA content during gestation between wild-type and SMP30/GNL knockout mice, which cannot synthesize AA, and found no significant differences between them. These results indicated that, although AA synthesis might occur in the ovaries, the amount of AA which is synthesized in ovaries must be quite low and insufficient to influence the AA content in ovary.

Non-destructive measurement of ascorbic acid content in bell peppers by VIS-NIR and SWIR spectrometry

The present study created a basis for development of a fast, non-destructive method to measure ascorbic acid content during various growth stages of three bell pepper cultivars: ‘Ever Green’, ‘No. 117’ and ‘Celica’. Fruit were tagged at the flowering stage and picked weekly during 9 weeks of growth, until fully ripe. Visible and near-infrared (VIS–NIR) spectra in the range 477–950nm were obtained in reflectance mode from intact peppers with a USB2000 mini-spectrometer. Short-wave infrared (SWIR) spectra in the range 850–1888nm were obtained in reflectance mode from the same sampled peppers with a Liga Spectrometer. Fruit flesh samples were cut from the area scanned for spectral measurements, and destructively analyzed for ascorbic acid content. The highest ascorbic acid content was measured in the green variety ‘Ever Green’ (148.1mg per 100g). Varieties ‘Ever Green’ and ‘No. 117’ accumulated significantly higher concentrations of ascorbic acid than ‘Celica’, and consistent and significant differences were found between the premature, green and mature stages of all three cultivars. Partial Least-Squares (PLS) regression was used in spectral model development. Comparisons were made between the PLS regression analysis of the reflectance spectra (R), its first derivative (D1R), the log(1/R) and its first (D1log(1/R)) and second derivative (D2log(1/R)). VIS–NIR and SWIR spectroscopy measurements showed good correlation (r2=0.76) with changes in ascorbic acid content. The PLS regression models were able to predict ascorbic acid content for all three cultivars, with 15.1–18.9mg per 100g cross-validation error (RPD=2–2.4). The method offers potential for non-destructive detection of changes in ascorbic acid content during growth and maturation of intact bell peppers.

POSTHARVEST CONSERVATION OF MATURE-GREEN AND RIPE 'PALUMA' GUAVA STORED AT TWO TEMPERATURES

ISHS XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Postharvest Technology in the Global Market POSTHARVEST CONSERVATION OF MATURE-GREEN AND RIPE 'PALUMA' GUAVA STORED AT TWO TEMPERATURES

미생물을 이용한 후발효차의 발효기간별 항산화 성분 및 활성의 변화

위생적으로 안전성이 확보된 후발효차를 제조하기 위해 Bacillus subtilis, Saccharomyces cerevisiae 및 Lactobacillus bulgaricus를 이용하여 후발효차를 제조한 후 발효시간에 따른 항산화 성분 및 활성의 변화를 측정하였다. 후발 효차의 ascorbic acid의 함량은 발효기간 내내 균종에 관계없이 녹차(66.74 ㎎%)에 비하여 비교적 낮은 함량(43.62～62.84 ㎎%)을 보였고 산소와의 접촉을 최소화한 L. bulgaricus 균에 의한 발효가 비교적 적은 변화를 보였다. Polyphenol 화합물의 함량은 녹차의 경우 14.88%였으며 후발효차는 11.54～14.12%로 세 균주 모두 발효가 진행됨에 따라 함량이 다소 감소하였다. 실험에 사용한 녹차의 flavonoid 함량은 7.78 ㎎%였으며 미생물을 이용한 후발효차의 경우에는 4.33～7.88 ㎎%로 대부분 녹차에서의 함량보다 적은 것으로 나타났다. 항산화 활성의 경우, 녹차의 DPPH 전자공 여능 및 ABTS 항산화 활성은 각각 87.47% 및 203.22 AEAC ㎎%였으나 발효기간에 따른 후발효차에서는 녹차에 비하여는 낮은 활성을 보여 후발효차 제조 시 어느 정도 항산화 성분의 함량 및 활성이 다소 감소하게 되지만 미생물을 이용하여 후발효차를 제조 시 위생적이고 기호도가 우수한 제품을 생산할 수 있는 것으로 판단되었다.

Changes in ascorbic acid content of fresh apricot fruits under fungal pathogenesis

The degradation of ascorbic acid content of fresh apricot fruits infected with Rhizopus stolonifer, Aspergillus japonicus, A. niger and Penicillium citrinum was studied. The experimental results revealed that there was decrease in vitamin C content of both healthy and infected fruits with an increase in incubation period. Fruits infected with R. stolonifer, A. japonicus, A. niger and P. citrinum had lost Vitamin C by 85%± 4.08, 78.3%± 2.36, 60%± 4.08 and 34.97%± 4.08 respectively after 6 days of pathogenesis whereas the healthy fruits still had 90%± 0.19 of vitamin C after same period of incubation. The degradation of ascorbic acid was more in infected fruits in comparison to healthy fruits and this may be either due to the production of ascorbic acid degrading enzymes or due to increased respiration rate which may induce rapid oxidation of ascorbic acid in the fruit tissue.

Changes of Ascorbic Acid Content during the Process of Cooking

Changes of Ascorbic Acid Content during the Process of Cooking

Response of antioxidant activity to excess copper in two cultivars of Brassica campestris ssp. chinensis Makino

Changes in ascorbic acid content and antioxidant enzyme activities were investigated in non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino) leaves of ‘Wutacai’ and ‘Erqing’ exposed to excess copper (Cu). Cu treatment reduced the fresh weight of shoot and root by 57% and 46% in ‘Wutacai’, and 60 and 54% in ‘Erqing’, respectively. The accumulation of copper in leaves was higher in ‘Wutacai’ than that in ‘Erqing’. Compared to the control, ascorbic acid (AsA) contents were significantly decreased after copper treatment in both cultivars, while they were higher in ‘Wutacai’ than in ‘Erqing’, which may explain the higher copper-tolerance of ‘Wutacai’ with higher copper accumulation. The higher AsA contents of ‘Wutacai’ resulted from their lower activities of degrading enzymes, such as ascorbate oxydase (AAO) and ascorbate peroxidase (APX), as well as the increasing activity of dehydroascorbate reductase (DHAR) after copper treatment compared with ‘Erqing’. Copper stimulated superoxide dismutase (SOD) activity in both cultivars, but for catalase (CAT), there was little difference between both cultivars. Peroxidases (POD) activity was decreased after copper treatment in ‘Erqing’, while in ‘Wutacai’, it was significantly increased at 14 days, and POD activity was higher in ‘Wutacai’ than that in ‘Erqing’ at 21 and 28 days. Therefore, the induced increasing activity of POD in ‘Wutacai’ also played an important role in its copper tolerance.

Ascorbic acid metabolism in fruits: activity of enzymes involved in synthesis and degradation during ripening in mango and guava

AbstractBACKGROUND: Ascorbic acid is a very important compound for plants. It has essential functions, mainly as an antioxidant and growth regulator. Ascorbic acid biosynthesis has been extensively studied, but studies in fruits are very limited. In this work we studied the influence of five enzymes involved in synthesis (L‐galactono‐1,4‐lactone dehydrogenase, GalLDH, EC 1.3.2.3), oxidation (ascorbate oxidase, EC 1.10.3.3, and ascorbate peroxidase, APX, EC 1.11.1.11) and recycling (monodehydroascorbate reductase, EC 1.6.5.4, and dehydroascorbate reductase, DHAR, EC 1.8.5.1) on changes in ascorbic acid content during development and ripening of mangoes (Mangifera indica L. cv. Keitt) and during the ripening of white pulp guavas (Psidium guayava L. cv. Paloma).RESULTS: It was found that there was a balance between the activities of GalLDH, APX and DHAR, both in mangoes and guavas.CONCLUSIONS: Equilibrium between the enzymatic activities of synthesis, catabolism and recycling is important for the regulation of ascorbic acid content in mango and guava. These results have contributed to understanding some of the changes that occur in ascorbic acid levels during fruit ripening. Copyright © 2008 Society of Chemical Industry

Effects of modified atmosphere packaging with various sizes of silicon gum film window on the storage of Agrocybe Chaxingu Huang and the modelling of its respiration rate

AbstractAn Agrocybe chaxingu Huang packaged in 5% O2‐ and 10% CO2‐modified atmospheres with different sizes (0, 0.5, 1.0 and 1.5cm2) of silicon gum film window was stored at a temperature of 3 ± 1°C for 20 days. Changes of ascorbic acid content, titratable acidity, electrolyte leakage and sensory characteristic were evaluated. Significant differences were found among the packages with different sizes of silicon gum film window on ascorbic acid content, titratable acidity, electrolyte leakage, general appearance, firmness and odour after 8, 8, 12, 12, 12 and 4 days of storage, respectively. The package with a 1.0cm2 silicon gum film window was the most effective for keeping the quality of Agrocybe chaxingu Huang. Based on the optimum storage condition in this study, an enzyme kinetics respiration model was set successfully and the applicability of the enzyme kinetics respiration model was verified by using the packages of Agrocybe chaxingu Huang with weights of 105 and 125g, respectively. Copyright © 2007 John Wiley & Sons, Ltd.

Regulation of Water Deficit-Induced Abscisic Acid Accumulation by Apoplastic Ascorbic Acid in Maize Seedlings

Abstract: Water deficit-induced abscisic acid (ABA) accumulation is one of the most important stress signaling pathways in plant cells. Redox regulation of cellular signaling has currently attracted particular attention, but much less is known about its roles and mechanisms in plant signaling. Herein, we report that water deficit-induced ABA accumulation could be regulated by ascorbic acid (AA)-controlled redox status in leave apoplast. The AA content in non-stressed leaves was approximately 3 μmol/g FW, corresponding to a mean concentration of 3 mmol/L in a whole cell. Because AA is mainly localized in the cytosol and chloroplasts, the volume of which is much smaller than that of the whole cell, AA content in cytosolic and chloroplast compartments should be much higher than 3 mmol/L. Water deficit-induced ABA accumulation in both leaf and root tissues of maize seedlings was significantly inhibited by AA and reduced glutathione (GSH) at concentrations of 500 μmol/L and was completely blocked by 50 mmol/L AA and GSH. These results suggest that the AA-induced inhibition of ABA accumulation should not occur at sites where AA exists in high concentrations. Although water deficit led to a small increase in the dehydroascorbic acid (DHA) content, no significant changes in AA content were observed in either leaf or root tissues. When compared with the whole leaf cell, the AA content in the apoplastic compartment was much lower (i.e. approximately 70 nmol/g FW, corresponding to 0.7 mmol/L). Water deficit induced a significant decrease (approximately 2.5-fold) in the AA content and an increase (approximately 3.4-fold) in the DHA content in the apoplastic compartment, thus leading to a considerably decreased redox status there, which may have contributed to the relief of AA-induced inhibition of ABA accumulation, alternatively, promoting water deficit-induced ABA accumulation. Reactive oxygen species (ROS) could not mimic water deficit in inducing ABA accumulation, suggesting that the inhibition of ABA accumulation by AA or GSH was not related to their ROS-scavenging ability. The results of the present study suggest that the redox status in the apoplastic compartment, as determined by AA and DHA, may play a vital role in the regulation of the signaling process for water deficit-induced ABA accumulation. (Managing editor: Ping HE)