Chilling Injury In Cucumbers Research Articles

Nitric oxide alleviates chilling injury in cucumber (Cucumis sativus L.) fruit by regulating membrane lipid and energy metabolism

ABSTRACT Chilling injury is the dominant factor for quality deterioration and marketability suffers of cucumber fruit during low-temperature storage. Nitric oxide (NO) is a kind of endogenous signaling molecule that significantly regulates the abiotic stress response. In the current investigation, the membrane lipid and energy metabolism were investigated after cucumber fruit was exposed to a sodium nitropruside (SNP) solution that acts as a NO donor before being kept at 4°C for 12 days. The results illustrated that SNP treatment reduced chilling injury and lightened the increase in membrane permeability under cold stress, maintaining a better quality. Subsequently, SNP regulated lipid metabolism by reducing the expression of genes encoding PLA, PLD, lipase, and LOX and decreasing the activities. Compared to the control, the SNP-treated fruit exhibited higher ATP and EC (energy charge) levels. Moreover, SNP-treated suppressed the decrease of H+-ATPase, Ca2+-ATPase, SDH, and CCO activity, which is involved in energy metabolism. The above results showed that exogenous nitric oxide might be an effective method to alleviate the chilling damage in postharvest cucumber fruit by modifying membrane lipids and energy metabolism.

Physical, chemical, and physiological characterization of the reactions preceding chilling injury–induced cell membrane damage in cucumber

Chilling injury in cucumber is commonly thought to begin with cell membrane damage caused by reactive oxygen species, which results in ion leakage from the tissue. However, additional short-term storage at ambient temperature after cold storage can accelerate the appearance of damage, and the different types of vegetables exhibit distinct symptoms. We hypothesized that cell membrane damage is a secondary reaction, and that preceding responses in the tissue lead to irreversible changes. To explore these responses in cucumber tissue during cold storage, we employed several techniques, including ion leakage measurements, bio-electrochemical impedance spectroscopy, X-ray computed tomography, nuclear magnetic resonance–based metabolite profiling, and transcriptome analysis. Our time-course comparison of different storage conditions (2 °С, 5 °С, 10 °С, and 15 °С for 0–14 d) indicated that several responses preceded detectable ion leakage–associated cell membrane damage. Specifically, the cold-stored samples exhibited abnormal electrolyte distribution and marked changes in metabolite levels and gene expression related to the tricarboxylic acid (TCA) cycle, which is critical for generating energy for homeostasis. Moreover, samples stored at 2 °С followed by 15 °С showed earlier initiation of tissue responses in metabolite and gene expression profiles, suggesting the occurrence of irreversible changes, possibly in the TCA cycle. These findings suggest that the critical response to chilling injury may occur prior to cell membrane damage, likely due to metabolic imbalances in the TCA cycle.

Fucoidan treatment alleviates chilling injury in cucumber by regulating ROS homeostasis and energy metabolism.

Chilling injury is a major hindrance to cucumber fruit quality during cold storage. In this study, we evaluated the effects of fucoidan on fruit quality, reactive oxygen species homeostasis, and energy metabolism in cucumbers during cold storage. The results showed that, compared with the control cucumber fruit, fucoidan-treated cucumber fruit exhibited a lower chilling injury index and less weight loss, as well as reduced electrolyte leakage and malondialdehyde content. The most pronounced effects were observed following treatment with fucoidan at 15 g/L, which resulted in increased 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical scavenging rates and reduced superoxide anion production rate and hydrogen peroxide content. The expression and activity levels of peroxidase, catalase, and superoxide dismutase were enhanced by fucoidan treatment. Further, fucoidan treatment maintained high levels of ascorbic acid and glutathione, and high ratios of ascorbic acid/dehydroascorbate and glutathione/oxidized glutathione. Moreover, fucoidan treatment increased the activities of ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase and their gene expression. Fucoidan treatment significantly delayed the decrease in ATP and ADP, while preventing an increase in AMP content. Finally, fucoidan treatment delayed the decrease of energy charge and the activities and gene expression of H+-ATPase, Ca2+-ATPase, cytochrome c oxidase, and succinate dehydrogenase in cucumber fruits. Altogether, our findings indicate that fucoidan can effectively enhance antioxidant capacity and maintain energy metabolism, thereby improving cucumber cold resistance during cold storage.

Assessing Chilling Injury in Cucumber Seedlings Using Chlorophyll Fluorescence Based on a Quantum Genetic Algorithm and Support Vector Regression Model

HighlightsA method is proposed to analyze chilling injury in cucumber seedlings.A mutual information method was adopted to determine model output.Different modeling approaches were compared for improving accuracy.The optimal model input type was determined and discussed.Abstract. Low temperature limits photosynthesis and leads to reduced production in plants. Accurate monitoring of the physiological state of cucumber (Cucumis sativus L.) seedlings and assessing their chilling injury are of great importance for the off-season cucumber industry. Dark chlorophyll fluorescence parameters have been proven to be efficient for revealing environmental stress on plant growth. We used seedlings of cucumber cultivar Bonai 14-3 to test a nested set of fluorescence parameters to assess the response characteristics of dark chlorophyll fluorescence parameters during eight days at low temperatures. Mutual information analysis showed that the dark chlorophyll fluorescence parameter Fv/Fo, an indicator of the potential activity of photosystem II, gave the strongest correlation with stage of chilling injury. We compared three Fv/Fo prediction models with different inputs, constructed using a quantum genetic algorithm support vector regression method. The model showed the highest accuracy when the inputs were Fv and Fo measured before low-temperature treatment, coupled with temperature, and duration. The coefficient of determination of the training and testing sets were both greater than 0.98. The root mean square error and the mean absolute error were both less than 0.15. This model was able to achieve accurate prediction of Fv/Fo for seedlings in a low-temperature environment, providing a potential method for non-destructive analysis and diagnosis of cucumber chilling injury. Keywords: Chlorophyll fluorescence parameters, Low temperature, Mutual information, Prediction.

Pre-storage Application of L-arginine Alleviates Chilling Injury and Maintains Postharvest Quality of Cucumber (Cucumis sativus)

Chilling injury in cucumber is the major issue under low temperature storage, which substantially affects cosmetic quality and market value of fruits. Present study was aimed to assess the effect of L-arginine to alleviate surface pitting caused due to chilling injury and response of various quality attributes during cold storage (5 ± 1 °C; RH 90 ± 5%). Cucumber cv. ‘7003’ fruits were treated with different concentrations of L-arginine (0.0, 0.5, 1.0 and 1.5 mM) and stored for 16 days. Fruits were removed at 4 days storage interval followed by 1 day of conditioning (22 ± 2 °C) before quality analysis. Visual quality, fruit colour, decay, fruit weight loss, firmness, chilling injury (CI), electrolyte leakage, taste, texture, flavour, aroma, soluble solids content (SSC), titratable acidity (TA), sugar: acid ratio (SSC/TA ratio) and ascorbic acid content were measured for cucumber fruits. Overall, it was noted that L-arginine treated fruits showed lower fruit weight loss and electrolyte leakage, and maintained taste, texture, aroma, SSC, and sugar: acid ratio during storage. Fruits treated with 0.5 mM L-arginine had significantly reduced chilling injury and decay, maintained fruit colour, firmness and flavour, and displayed higher ascorbic acid content compared with control. Conclusively, pre-storage application of L-arginine (0.5 mM) can be employed as promising technique to alleviate postharvest chilling injury and maintain fruit quality of cucumber under cold storage.

Enhancing chlorophyll fluorescence imaging under structured illumination with automatic vignetting correction for detection of chilling injury in cucumbers

Chlorophyll fluorescence imaging (CFI) is useful for detecting physiological disorders or defects for green-skinned horticultural products, because defective and normal plant tissues would have different responses to ultraviolet (UV) or short-wavelength visible excitation. This study was intended to evaluate the effectiveness of a new CFI approach by using structured illumination coupled with a proposed automated method for vignetting correction of chlorophyll fluorescence images, for enhanced detection of chilling injury in cucumbers. A CFI system with UV-blue light as an excitation source under structured illumination was assembled. Spectral images over the spectral region of 660–800 nm in 5 nm increments were first acquired from chilling-treated cucumbers under uniform UV-blue illumination to determine appropriate wavebands for implementation of CFI under structured illumination. Further experiment was conducted on a larger group of chilling treated cucumbers to acquire chlorophyll fluorescence images under structured illumination for two wavebands centered at 675 nm and 750 nm. An automatic method for vignetting correction of fluorescence images was proposed by using a modified bi-dimensional empirical mode decomposition (BEMD) technique. Results showed that the chlorophyll fluorescence spectra of cucumbers were characterized by two emission peaks around the regions of 685–690 nm and 740–745 nm respectively. The proposed BEMD method was effective for vignetting correction of fluorescence images, which eliminates the need of using a physical fluorescence target for image correction. Moreover, compared to uniform illumination, structured illumination was found to provide significantly better fluorescence images in terms of the image sharpness and contrast between the normal and chilling-injury tissues, which were inductive to enhancing the detection of chilling injury in cucumbers.

Postharvest application of MeJA and NO reduced chilling injury in cucumber (Cucumis sativus) through inhibition of H2O2 accumulation

Cucumber is a chilling-sensitive vegetable, which is susceptible to chilling injury during storage and shipment at temperatures below 7–10°C. MeJA and NO have been shown to be able to induce chilling tolerance, but how they are related and how H2O2 is involved in the chilling responses they trigger remains unclear. Here postharvest application of 10μM MeJA and 1mM SNP, a NO donor, significantly reduced chilling injury of cucumbers stored at 5°C. MeJA and SNP reduced H2O2 in cucumber during storage, suggesting that H2O2 may not function as a second messenger in chilling responses activated by MeJA or NO, and that, both MeJA and NO alleviated CI by inhibiting H2O2 generation. This is confirmed by the evidence that diphenylene iodonium further strengthened the chilling tolerance induced by MeJA or SNP. The lower H2O2 induced by MeJA and NO was coincident with enhanced catalase activity and gene expression, suggesting that CAT played an important role in control of H2O2 accumulation. Two more independent experiments showed that, L-NAME and cPTIO, inhibitors of endogenous NO accumulation, significantly compromised MeJA-induced chilling tolerance, but IBU and SHAM, inhibitors of endogenous jasmonic acids biosynthesis, did not affect the chilling tolerance activated by SNP, suggesting MeJA may function upstream of and depend on NO in the signaling pathway that activates chilling tolerance in cucumber.

Nondestructive detection of chilling injury in cucumber fruit using hyperspectral imaging with feature selection and supervised classification

Chilling injury, as a physiological disorder in cucumbers, occurs after the fruit has been subjected to low temperatures. It is thus desirable to detect chilling injury at early stages and/or remove chilling injured cucumbers during sorting and grading. This research was aimed to apply hyperspectral imaging technique, combined with feature selection methods and supervised classification algorithms, to detect chilling injury in cucumbers. Hyperspectral reflectance (500–675nm) and transmittance (675–1000nm) images for normal and chilling injured cucumbers were acquired, using an in-house developed online hyperspectral imaging system. Three feature selection methods including mutual information feature selection (MIFS), max-relevance min-redundancy (MRMR), and sequential forward selection (SFS) were used and compared for optimal wavebands selection. Supervised classifications with naïve Bayes (NB), support vector machine (SVM), and k-nearest neighbor (KNN) were then implemented for the two-class (i.e., normal and chilling) and three-class (i.e., normal, lightly chilling, and severely chilling) classifications based on the spectral and image analysis at selected two-band ratios. It was found that the majority of the optimal wavebands selected by MIFS, MRMR, and SFS for both two-class and three-class classifications were from the spectral transmittance images in the short-near infrared region. The SFS feature selection method together with the SVM classifier resulted in the best overall classification accuracy of 100%, and the overall accuracy of 90.5% for the three-class classification, based on the spectral analysis. The classification results based on the textural features (first-order statistics and second-order statistics features) extracted from the optimal two-band ratio images were comparable to those achieved using the spectral features, with the best overall accuracies of 100% and 91.6% for the two-class and the three class classifications, respectively. These results demonstrated the potential of hyperspectral imaging technique for online detection of chilling injury in cucumbers.

Postharvest chitosan-g-salicylic acid application alleviates chilling injury and preserves cucumber fruit quality during cold storage

The effect of salicylic acid with and without chitosan, or a chitosan-g-salicylic acid complex, on chilling injury and post-harvest quality of cucumber stored at 2°C for 12days plus 2days at 20°C was investigated. The results showed the chitosan-g-salicylic acid coating inhibited chilling injury better than salicylic acid alone or with chitosan. Chitosan-g-salicylic acid also reduced weight loss and respiration rate, limited increases in malondialdehyde content and electrolyte leakage, and maintained higher total soluble solids, chlorophyll and ascorbic acid content. Furthermore, this coating increased the endogenous salicylic acid concentrations and antioxidant enzyme activities including superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase in cucumber during storage. Our study suggests that chitosan-g-salicylic acid alleviated chilling injury in cucumber through sustained-release of salicylic acid and the higher antioxidant enzymes concentrations.

Backcross introgression of plastomic factors controlling chilling tolerance into elite cucumber (Cucumis sativus L.) germplasm: early generation recovery of recurrent parent phenotype

Environmental stresses such as chilling temperatures can decrease germination, emergence, flower and fruit development, marketable yield, and postharvest fruit storage longevity in cucumber (Cucumis sativus L.). While response to chilling injury in cucumber is controlled by simple plastidic (maternal) and nuclear (paternal) factors, no chilling tolerant U.S. processing varieties are commercially available. Furthermore, even though three single nucleotide polymorphic sites have been identified as plastid components associated with chilling tolerance in cucumber, it is not known how these factors interact with nuclear factors controlling economically important traits. Therefore, an experiment was designed to evaluate the rate of recovery of the chilling susceptible (cytoplasm) genotype during introgression backcrossing (IB), where it was used as a recurrent parent after the initial mating to a line possessing chilling tolerant cytoplasm (donor parent). Phenotypic yield and quality trait data were collected on processing type backcross progeny (BC1–5 and BC2S3) derived from an initial ‘Chipper’ (tolerant) × line M 29 (susceptible) mating, and rate of progression to the recurrent parent was determined by simple sequence repeat marker and morphological trait analyses. Substantial degrees of the recurrent parent phenotype and nuclear genome were recovered by the BC2 generation (P = 0.001), with nearly complete recovery of recurrent parental traits and its nuclear genome occurring by the BC3. General combining ability (GCA) of derived BC2S3 lines was significant for yield, yield/plant, length (L), diameter (D), and L:D ratios. The BC2S3 line GCA and rate of progression towards the recurrent parent for economically important traits suggests that elite chilling tolerant cucumber germplasm can be developed rapidly through IB and marker genotyping.

Effect of yeast saccharide treatment on nitric oxide accumulation and chilling injury in cucumber fruit during cold storage

The effects of a saccharide fraction prepared from yeast cell walls on chilling injury and endogenous nitric oxide (NO) generation in cucumbers and the role of NO in yeast saccharide (YS)-induced cold tolerance of the fruit during postharvest storage, were investigated. Chilling injury index, malondialdehyde (MDA) content, and ion leakage of fruit treated with 0.5g/L YS were significantly reduced as compared with those of control fruit stored at 4°C, showing that YS treatment may reduce chilling injury in cucumber. Moreover, treatment with YS triggered a marked increase in endogenous NO levels. An NO scavenger and NO synthase inhibitors not only diminished YS-triggered NO generation but also suppressed YS-enhanced cold tolerance. Together, our results indicate that YS could have potential postharvest application for reducing chilling injury in cucumber fruit. Furthermore, we found that YS-induced cold tolerance is linked with the induction of endogenous NO accumulation.

Reduced chilling injury in cucumber by nitric oxide and the antioxidant response

Cucumber fruit were pre-treated with 25μll−1 nitric oxide (NO) for 12h at 20°C, and then stored at 2±1°C and 95% relative humidity for 15days. Chilling injury index, membrane permeability, lipid peroxidation, superoxide anion (O2-) production rate, H2O2 content, activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), and DPPH-radical scavenging activity were measured. The results showed that the application of NO at 25μll−1 was most effective in reducing CI in cucumber fruit. The treatment reduced the increases in membrane permeability and lipid peroxidation, delayed the increases in both O2- production rate and H2O2 content. The NO-treated fruit exhibited significantly higher activities of SOD, CAT, APX and POD and higher DPPH-radical scavenging activity than control fruit during the storage. The overall results suggest that NO enhanced chilling tolerance in cucumber fruit by improving the antioxidative defence system.

Sequencing cucumber (Cucumis sativus L.) chloroplast genomes identifies differences between chilling-tolerant and -susceptible cucumber lines

Chilling injury in cucumber (Cucumis sativus L.) is conditioned by maternal factors, and the sequencing of its chloroplast genome could lead to the identification of economically important candidate genes. Complete sequencing of cucumber chloroplast (cp)DNA was facilitated by the development of 414 consensus chloroplast sequencing primers (CCSPs) from conserved cpDNA sequences of Arabidopsis (Arabidopsis thaliana L.), spinach (Spinacia oleracea L.), and tobacco (Nicotiana tabacum L.) cpDNAs, using degenerative primer technologies. Genomic sequence analysis led to the construction of 301 CCSPs and 72 cucumber chloroplast-specific sequencing primers (CSSPs), which were used for the complete sequencing of cpDNA of Gy14 (155 525 bp) and 'Chipper' (155 524 bp) cucumber lines, which are, respectively, susceptible and tolerant to chilling injury (4 degrees C for 5.5 h) in the first leaf stage. Comparative cpDNA sequence analyses revealed that 1 sequence span (located between genes trnK and rps16) and 2 nucleotides (located in genes atpB and ycf1) differed between chilling-susceptible and -tolerant lines. These sequence differences correspond to previously reported maternally inherited differences in chilling response between reciprocal F1 progeny derived from these lines. Sequence differences at these 3 cpDNA sites were also detected in a genetically diverse array of cucumber germplasm with different chilling responses. These and previously reported results suggest that 1 or several of these sequences could be responsible for the observed response to chilling injury in cucumber. The comprehensive sequencing of cpDNA of cucumber by CCSPs and CSSPs indicates that these primers have immediate applications in the analysis of cpDNAs from other dicotyledonous species and the investigation of evolutionary relationships.

Two-color mixing for classifying agricultural products for safety and quality

We show that the chromaticness of the visual signal that results from the two-color mixing achieved through an optically enhanced binocular device is directly related to the band ratio of light intensity at the two selected wavebands. A technique that implements the band-ratio criterion in a visual device by using two-color mixing is presented here. The device will allow inspectors to identify targets visually in accordance with a two-wavelength band ratio. It is a method of inspection by human vision assisted by an optical device, which offers greater flexibility and better cost savings than a multispectral machine vision system that implements the band-ratio criterion. With proper selection of the two narrow wavebands, discrimination by chromaticness that is directly related to the band ratio can work well. An example application of this technique for the inspection of carcasses chickens of afficted with various diseases is given. An optimal pair of wavelengths of 454 and 578 nm was selected to optimize differences in saturation and hue in CIE LUV color space among different types of target. Another example application, for the detection of chilling injury in cucumbers, is given, here the selected wavelength pair was 504 and 652 nm. The novel two-color mixing technique for visual inspection can be included in visual devices for various applications, ranging from target detection to food safety inspection.

Inheritance of Chilling Injury: A Maternally Inherited Trait in Cucumber

Chilling temperatures (≤12°C) can cause substantial economic damage to cucumber (Cucumis sativus L.) plants. Previous studies suggest chilling tolerance trait is controlled by nuclear gene(s). To investigate inheritance of chilling injury in cucumber, cucumber lines [susceptible GY14 (P1), tolerant `Chipper' (P2), and tolerant `Little John' (P3)], and their exact reciprocal F1 and F2 cross-progeny were evaluated to determine the inheritance of chilling injury at the first true-leaf stage when challenged at 4 °C for 5.5 hours. The mean chilling ratings [1(trace) to 9(dead)] of progeny comparisons were F1(P1 × P2) = 6.2 vs. F1(P2 × P1) = 1.6; F2(P1 × P2) = 6.4 vs. F2(P2 × P1) = 2.7; F1(P1 × P3) = 5.4 vs. F1(P3 × P1) = 1.7; and F2(P1 × P3) = 5.8 vs. F2(P3 × P1) = 2.2. These data suggest that chilling tolerance was maternally inherited as is the chloroplast genome in cucumber. Parents, reciprocal F1, and F2 progeny were evaluated for variation using random amplified polymorphism DNA (RAPD). Although no maternally inherited RAPD markers were detected, polymorphic and paternally inherited RAPD bands AD21249, AV8916, and AV8969 amplified by AD2 and AV8 primers were cloned and sequenced. A BLAST search of these sequences suggested that their origin is likely cucumber mitochondrial DNA. These results indicate that the mitochondria genome is not associated with the chilling tolerant trait because this genome is paternally inherited in progeny derived from this reciprocal mating. Therefore, the results of maternally inherited chilling tolerant trait and paternally transmitted mitochondria genome support that the chilling tolerant trait as identified is likely associated with the chloroplast genome which is maternally transmitted in cucumber.

Modified atmosphere packaging alleviates chilling injury in cucumbers

Abstract Cucumbers (Cucumis sativus L.) packaged in perforated or sealed 31.75 μm (1.25 mil) low density polyethylene (LDPE) bags were found to have less severe chilling injury than nonwrapped fruit in storage at 5 °C and 90–95% relative humidity. The onset of chilling injury was also delayed by the LDPE packaging compared to the nonpackaged control. The concentrations of CO2 increased to 3% while O2 levels decreased to 16% in the sealed bags. Fruit in the sealed bags had the least decay. The O2 and CO2 concentrations inside the perforated bags changed very little from the ambient atmosphere. However, there was a marked difference in the weight loss between nonwrapped cucumbers and fruit from perforated or sealed bags. The weight loss of nonwrapped fruit reached 9% in 18 days while perforated and sealed samples lost less than 1% during the same period. Chilling stress induced increases in putrescine levels in all treatments but the sealed fruit had the highest levels of putrescine. Sealed fruit and perforated fruit also had higher content of spermidine than non-wrapped fruit. These high levels of polyamines may have contributed to the increase of chilling tolerance in fruit from perforated and sealed packages.

Chilling Injury in Cucumbers (Cucumis sativa L.) Associated with Lipid Peroxidation as Measured by Ethane Evolution

ABSTRACTThe development of chilling injury in cucumbers stored at 4°C and 95% RH was evaluated. Irreversible damage due to chilling required 7 to 10 days as indicated by increases in tissue electrolyte leakage (from 30 to 70%), stress ethylene production (to 30‐60 pMol g_1 hr−1) and visual manifestations of injury. Low levels of ethane evolution (<1 pMol g−1 hr−1) were observed for unchilled and continuously chilled fruits. Upon rewarming, ethane evolution was stimulated by an order of magnitude following a prior chilling exposure of at least 7 days. These results indicate that the potentiation of lipid peroxidation in chilled cucumbers is associated with the onset of irreversible injury.

Chilling-injury in cucumbers. V. Polysaccharide changes in cell walls

A decline in the hot-water-soluble pectin and an increase in the hot-water-insoluble pectin were observed when cucumber fruits were subjected to chilling temperatures. Infrared absorption spectra revealed the presence of highly esterified carboxyl groups in the soluble pectin, and of free carboxyl groups in the insoluble pectin. An increase of the insoluble pectin during chilling was also found in other chilling-sensitive plants. From these results it is suggested that a de-esterification of pectin and the concomitant increase of polymeric pectin takes place during chilling, making cell walls firmer, and that these pectic changes may be a characteristic common to a number of chilling-sensitive plants.