Pre-harvest Methyl Jasmonate Treatment Research Articles

Preharvest Methyl Jasmonate Treatment Affects the Mineral Profile, Metabolites, and Antioxidant Capacity of Radish Microgreens Produced without Substrate.

This study investigated the impact of Methyl Jasmonate (MeJA) application on the nutritional content and yield of five different colored radish microgreens. Microgreens were produced without substrate and subjected to 0.5 mM and 1.0 mM MeJA treatments on the 7th day, three days before harvest. The parameters measured included yield, dry matter, minerals, amino acids, secondary metabolites such as chlorophylls (Chls), anthocyanins, flavonoids, phenolics, glucosinolates (GSLs), vitamin C, and antioxidant capacity. MeJA at 1.0 mM generally improved yield and dry weight across cultivars, and all microgreens exhibited rich mineral and amino acid composition, with the influence of cultivar being more significant than MeJA treatment. However, MeJA enhanced all cultivars' anthocyanins, GSLs, phenolics, flavonoids, and antioxidant activities. Generally, as the antioxidant capacity is the primary factor influencing the nutritional quality of microgreens, MeJA-treated microgreens, especially with selected superior cultivars such as 'Asia purple' and 'Koregon red', could offer a potential for cultivation of value-added, eco-friendly microgreens with substrate-free cultivation.

Preharvest application of MeJA enhancing the quality of postharvest grape berries via regulating terpenes biosynthesis and phenylpropanoid metabolisms

Methyl jasmonate (MeJA) is an important phytohormone that regulates the development of grape, but the effect and underpin mechanism of its preharvest application on secondary metabolites accumulation in postharvest grape berries are still unclear. In this study, the transcriptome profiles combined with metabolic components analysis were used to determine the effect of preharvest MeJA application on the quality formation of postharvest rose-flavor table grape Shine Muscat. The results indicated that preharvest MeJA treatment had no significant effect on TSS content, but had a down-regulation effect on the accumulation of reducing sugar and titratable acid in the berries. The content of chlorophylls and carotenoids in treated berries was significantly higher than that of the control. Many phenolic components, such as trans-ferulic acid, resveratrol, quercetin, and kaempferol, were sensitive to MeJA and their contents were also significantly higher than that of the control under MeJA treatments during the shelf life. Compared with other volatile aroma components, terpenoid components were more sensitive to preharvest MeJA signals, the content of which presented an overall upward trend with increasing MeJA concentration and prolonging storage time. Furthermore, most of the differentially expressed genes in the general phenylpropanoid pathway and terpenoid biosynthesis pathway were up-regulated responding to MeJA signals. The most upregulated regulatory factors, such as VvWRKY72, VvMYB24, and VvWRI1, may be involved in MeJA signal transduction and regulation. Preharvest MeJA may be an effective technique for enhancing the quality of postharvest Shine Muscat grape berries, with its positive effect on enhancing the characteristic aroma and nutritional components.

Pre- or Post-Harvest Treatment with MeJA Improves Post-Harvest Storage of Lemon Fruit by Stimulating the Antioxidant System and Alleviating Chilling Injury.

Cold storage preserves lemon fruit quality; however, it can result in significant chilling injury (CI). The effects of pre- and post-harvest methyl jasmonate (MeJA) treatments at four concentrations (0, 0.1, 0.3, and 0.5 mM) on CI and sensory quality of lemons during 80 d of storage at 7-10 °C were investigated. Both pre- and post-harvest MeJA treatments reduced CI, weight loss (WL) and maintained higher firmness, total soluble solids (TSS), and total acidity (TA) than in the controls. Antioxidant enzyme activities decreased in the control fruit but increased in both pre- and post-harvest MeJA-treated fruit. In addition, phospholipase D (PLD) and lipoxygenase (LOX) activities and malondialdehyde (MDA) content were higher in the control than in the MeJA-treated fruit. Pre-harvest MeJA treatment generally preserved fruit better than post-harvest MeJA treatment, with the best results observed when MeJA was applied at 0.3 mM, which enhanced the antioxidant system of the lemon fruits, thus reducing the post-harvest incidence of chilling injury. These results have important implications for improved fruit quality post-harvest.

Preharvest Methyl Jasmonate Treatment Increased Glucosinolate Biosynthesis, Sulforaphane Accumulation, and Antioxidant Activity of Broccoli.

Broccoli is becoming increasingly popular among consumers owing to its nutritional value and rich bioactive compounds, such glucosinolates (GSLs) and hydrolysis products, which are secondary metabolites for plant defense, cancer prevention, and higher antioxidant activity for humans. In this study, 40 μmol/L methyl jasmonate (MeJA) was sprayed onto broccoli from budding until harvest. The harvested broccoli florets, stem, and leaves were used to measure the contents of GSLs, sulforaphane, total phenolics, and flavonoids, as well as myrosinase activity, antioxidant activity, and gene expression involved in GSL biosynthesis. The overall results revealed that GSL biosynthesis and sulforaphane accumulation were most likely induced by exogenous MeJA treatment by upregulating the expression of CYP83A1, SUR1, UGT74B1, and SOT18 genes. Exogenous MeJA treatment more remarkably contributed to the increased GSL biosynthesis in broccoli cultivars with low-level GSL content (Yanxiu) than that with high-level GSLs (Xianglv No.3). Moreover, MeJA treatment had a more remarkable increasing effect in broccoli florets than stem and leaves. Interestingly, total flavonoid content substantially increased in broccoli florets after MeJA treatment, but total phenolics did not. Similarly, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, trolox-equivalent antioxidant capacity (ABTS), and ferric-reducing antioxidant power (FRAP) were higher in broccoli floret after MeJA treatment. In conclusion, MeJA mediated bioactive compound metabolism, had positive effects on GSL biosynthesis, sulforaphane, and flavonoids accumulation, and showed positive correlation on inducing higher antioxidant activities in broccoli floret. Hence, preharvest supplementation with 40 μM MeJA could be a good way to improve the nutritional value of broccoli florets.

Preharvest spray application of methyl jasmonate promotes fruit colour and regulates quality in M7 Navel orange grown in a Mediterranean climate

Poor rind colour in cv. M7 Navel (Citrus sinensis L. Osbeck) at harvest time severely affects the profits of the growers in Western Australia. The effects of the preharvest spray application of different concentrations (0, 1.25, 2.5, 5.0 and 7.5 mM) of methyl jasmonate (MJ) on the rind colour development and fruit quality of M7 Navel were investigated at 6 or 3 weeks before anticipated harvest (WBAH) during 2015 and 2016. The preharvest spray application of MJ (5.0 or 7.5 mM) resulted in enhanced rind colour, reduced hue angle (ho) angle (55.7, 54.3) as well as increased citrus colour index (CCI) (11.0, 12.0) and total carotenoid levels (35.3, 58.3 mg kg-1) of flavedo, respectively in M7 Navel, during 2015 and 2016. During 2015, comparatively higher levels of total carotenoid (40.4 mg kg-1) were recorded when MJ was applied at 3 WBAH as a single spray. However, the time of MJ application did not influence hue angle (h°) and CCI. In 2015, all the preharvest MJ treatments except (1.25 mM) exhibited reduced fruit firmness. Furthermore, soluble solids concentration (SSC) in the fruit juice was reduced after MJ treatment. All the MJ treatments showed reduced levels of total sugars and organic acids in the juice, during 2015. In conclusion, MJ (5.0 or 7.5 mM) reduced h° but increased the total carotenoids levels and CCI in the flavedo of M7 Navel orange, when applied as a preharvest spray at 3 WBAH

Preharvest Methyl Jasmonate Treatment Increased the Antioxidant Activity and Glucosinolate Contents of Hydroponically Grown Pak Choi.

Vertical hydroponics farming has emerged as an alternative solution to feed the continuously growing world population. Additionally, recent studies reported that the exogenous treatments of jasmonic acid influence the phytochemical composition of Brassicaceae. We conducted this study to determine the effect of preharvest methyl jasmonate (MeJA) treatment on the phytochemical composition and antioxidant activities of soil- and hydroponically grown pak choi. An aqueous solution of 0.5-mM MeJA was sprayed to saturation on the aerial plant part three days before harvest. The harvested pak choi was freeze-dried and then powdered to measure the antioxidant activity and the contents of chlorophylls (Chls), total phenolics and flavonoids, and glucosinolates (GSLs). The overall results revealed that pak choi grown in vertical hydroponics had higher total Chls and total phenolics than those grown in soil in the greenhouse, regardless of MeJA treatment. Nevertheless, the GSLs content and total flavonoids increased significantly due to MeJA treatment in both growing systems, and the highest values were recorded in hydroponically grown MeJA-treated pak choi. Similarly, the 2, 2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, Trolox-equivalent antioxidant capacity (ABTS), oxygen radical absorbance capacity (ORAC), and ferric-reducing antioxidant power (FRAP) were highest in hydroponically grown MeJA-treated pak choi. Taken together, the preharvest foliar treatment of MeJA can be used to improve the phytochemical composition of pak choi grown in both growing systems. Interestingly, the results strongly support the use of MeJA treatment in the vertical hydroponics growing system compared to the conventional growing system in the soil. This indicates that supplementing the vertical hydroponic growing system with preharvest MeJA treatment could be the best option to improve both the yield per square meter and the quality of pak choi. Besides, MeJA-treated pak choi could be used as a value-added horticultural commodity, as its antioxidant activity increased after treatment. Moreover, after further studies, MeJA could also be applied to other Brassica vegetables to improve their GSL contents and antioxidant properties.

Priming of Defense Systems and Upregulation of MYC2 and JAZ1 Genes after Botrytis cinerea Inoculation in Methyl Jasmonate-Treated Strawberry Fruits.

Several attempts have been made to study the effects of methyl jasmonate (MeJA) on plants in the past years. However, the comparative effects of the number and phenological time of MeJA applications on the activation of defense systems is currently unknown in strawberries. In the present research, we performed three field treatments during strawberry (Fragaria × ananassa ‘Camarosa’) fruit development and ripening which consisted of differential MeJA applications at flowering (M3), and the large green (M2 and M3) and red ripe (M1, M2, and M3) fruit stages. We also checked changes in gene expression related to plant defense against Botrytis cinerea inoculation post-harvest. In M3 treatment, we observed an upregulation of the anthocyanin and lignin contents and the defense-related genes, encoding for chitinases, β-1,3-glucanases and polygalacturonase-inhibiting proteins, after harvest (0 hpi), along with the jasmonate signaling-related genes FaMYC2 and FaJAZ1 at 48 h after B. cinerea inoculation (48 hpi) during postharvest storage. Although we did not find differences in gray mold incidence between the MeJA treatments and control, these results suggest that preharvest MeJA treatment from the flowering stage onwards (M3) primes defense responses mediated by the upregulation of different defense-related genes and retains the upregulation of MYC2 and JAZ1 at 48 hpi.

Effects of Different Concentrations of Methyl Jasmonate on Fruit Quality of Citrus Huangguogan

In this study, methyl jasmonate (MeJA) was sprayed on the fruits of Huangguogan in shimian county in two different ways (whole tree spraying and fruit spraying) to study the effect of MeJA on the postharvest quality of the fruits of Huangguogan. The consequence showed that, compared with check (CK), each treatment could improve the fruit quality, 10 μmol·L-1MeJAspayed on Huangguoganperformed best. It significantly increased the sugar content, Vc content, total soluble solid (TSS in short) content and the sugar acid ratio of the Huangguogan, meanwhile decreased the content of titratable acid. These consequences indicated that preharvest MeJA treatment could improve the fruit quality of Huangguogan.

Preharvest application of methyl jasmonate increases crop yield, fruit quality and bioactive compounds in pomegranate 'Mollar de Elche' at harvest and during postharvest storage.

Previous reports have addressed the effectiveness of postharvest methyl jasmonate (MeJA) treatments on maintaining quality properties of pomegranate fruit during storage. However, there is no literature regarding the effects of preharvest MeJA treatments on pomegranate 'Mollar de Elche' crop yield, fruit ripening, quality attributes and bioactive compounds content (at harvest or after long-term storage), which were evaluated in this research. Preharvest MeJA treatments (1, 5, and 10 mmol L-1 ) increased pomegranate crop yield. MeJA at 1 and 5 mmol L-1 accelerated the on-tree ripening process, while it was delayed with 10 mmol L-1 . Losses in fruit weight, firmness and organic acids during storage at 10 °C were delayed in MeJA treated fruit, leading to quality maintenance. In addition, MeJA treatments improved arils colour due to increased concentration of total and individual anthocyanins, at harvest and during storage. Total phenolic and ascorbic acid contents and total antioxidant activity [hydrophilic (H-TAA) and lipophilic (L-TAA) fractions] were also higher in arils from treated pomegranate fruits than in controls. Preharvest treatments with MeJA could be a promising tool to improve pomegranate crop yield, fruit quality and its content in bioactive compounds at harvest and during storage. The higher effects were obtained with MeJA at 5 mmol L-1 dose, which could be the selected treatment for practical application purposes. © 2019 Society of Chemical Industry.

Pre‐harvest methyl jasmonate treatments increase antioxidant systems in lemon fruit without affecting yield or other fruit quality parameters

Jasmonic acid (JA) and its volatile derivative methyl jasmonate (MeJA) are hormones involved in the regulation of many processes in plants and act (when applied as a post- or pre-harvest treatment) to increase fruit bioactive compounds with antioxidant potential. However, there is no literature available regarding the effect of pre-harvest MeJA treatment on lemon fruit antioxidant systems, which was the aim of the present study. MeJA treatment (0.1, 0.5 and 1.0 mmol L-1 ) increased antioxidant compounds, such as phenolics, in the juice and flavedo of 'Fino' and 'Verna' lemons at harvest, with the most effective concentration being 0.1 mmol L-1 in both cultivars. In addition, catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities were also increased by MeJA treatment, with the highest increases being also found with 0.1 mmol L-1 . The increases in APX and CAT were maintained from one treatment to another during fruit development on the tree, whereas the increase on POD disappeared after 8-10 days of each treatment. For both antioxidant systems, the highest increases were found in lemon harvested at the commercial ripening stage. By contrast, crop yield, fruit ripening process and quality parameters were generally not affected by MeJA treatment. Preharvest MeJA treatment could be a useful tool for increasing antioxidant potential and the health beneficial effects of lemon fruit consumption, given the relationship between these properties and phenolic content. Moreover, the increased concentration of phenolics and the activity of antioxidant enzymes in the flavedo of MeJA treated fruit could increase lemon tolerance to chilling injury and decay during postharvest storage. © 2019 Society of Chemical Industry.

Effects of Pre-Harvest Methyl Jasmonate Treatments on Fruit Quality of Fuji Apples during Cold Storage

Araştırma hasat öncesi farklı dozlarda uygulanan (1120, 2240 ve 4480 mg L-1) metil jasmonatın (MeJA) soğukta muhafaza süresince Fuji elmasının meyve kalite özellikleri üzerine olan etkilerini belirlemek için yürütülmüştür. Araştırmada, M9 anacı üzerine aşılı 5 yaşlı Fuji elma ağaçları kullanılmıştır. MeJA, 3 farklı zamanda (ticari hasattan 2, 3, ve 4 hafta önce) ağaçlara uygulanmıştır. Soğukta muhafaza süresince ağırlık kaybı üzerine MeJA’nın etkisinin uygulama dozuna bağlı olarak değiştiği tespit edilmiştir. MeJA uygulama dozu arttıkça, meyve etinde meydana gelen yumuşama önemli derecede geciktirilmiştir. Depolama süresince, MeJA ile muamele olan meyvelerin SÇKM ve asitlik içeriği daha yüksek bulunmuştur. MeJA ile muamele olmuş meyvelerin pH değeri düşük olmasına rağmen, nişasta indeksi üzerine MeJA uygulamalarının önemli bir etkisi gözlemlenmemiştir. Sonuç olarak, soğukta muhafaza süresince meyve eti sertliğinde meydana gelen kaybın MeJA uygulaması ile geciktirilebileceği belirlenmiştir.

Pre-harvest methyl jasmonate treatments delayed ripening and improved quality of sweet cherry fruits

Abstract The effects of pre-harvest methyl jasmonate (MeJA) treatments on fruit quality attributes and bioactive compounds of sweet cherry fruits (Prunus avium L. cvs. 0900 Ziraat, Regina and Sweetheart) harvested at optimal and late harvest dates were investigated in this study. Measurements revealed that MeJA treatments were quite effective in retention of fruit flesh firmness of all three cultivars. It was observed that harvest could be delayed at least a week with MeJA treatments through maintaining flesh firmness. MeJA treatments slowed down color changes in all three cultivars. MeJA treatments did not have significant effects on fruit mass and geometric mean diameters, but decreased soluble solids content and titratable acidity of the fruits. In all three cultivars, total phenolics, antioxidant capacity and total monomeric anthocyanin values decreased with MeJA treatments. Delayed harvests increased bioactive contents of both the control and MeJA-treated fruits.

The Effect of Pre-Harvest Methyl Jasmonate Treatment on the Selected Volatile Compounds and Endogenous Hormones Contends in the Pulp of Grape Berries

Grapevine is one of the most valued and widely cultivated fruit crop worldwide, with their pleasant flavor and valuable health effects. During the consequent ripening at ambient temperature, the volatile compounds of table grape often decreased, to affect their sensory evaluation. The development of new and effective methods to increase the volatile compounds of berries is necessary. Present study was carried out to investigate the pre-harvest methyl jasmonate (MeJA) treatment on the selected volatile compounds and endogenous hormones content from ‘Shine Muscat’ berries pulp. The results indicated that, pre-harvest application of MeJA (0.1 mM or 0.01 mM) on grape berries generally enhanced the production of terpenes, like nerol, linalool, alpha-terpineol; While some C6 compounds were reduced, such as (E)-2-hexenol, hexanol, (Z)-3-hexenol, hexanal and (E)-2-hexenal. The endogenous hormones like IAA (indole acetic acid), ABA (abscisic acid) and JA (jasmonate acid) content were also changed after MeJA treatment. We also observed that MeJA palys a key role in fruit endogenous hormones level and volatile compounds by increasing the expression level of several related genes, such as aroma-related genes Vvter, Vv-syn and hormone-related genes VvOPR3, VvAuI, VvEth, VvNCED1. We hypothesize that, MeJA as an effective elicitor affects the volatile compounds by altering endogenous hormones level in berries pulp of ‘Shine Muscat’.

Accumulation of anthocyanins and flavonols in black currants (Ribes nigrum L.) by pre-harvest methyl jasmonate treatments.

Chemical elicitation is one of the most effective methods currently used to enrich plant foods in bioactive compounds. Methyl jasmonate (MJ) has been described as a very useful elicitor of some plant compounds, polyphenols among them. The objective of this study was to determine the effects of pre-harvest MJ application on the increase in the main flavonoids and the antioxidant properties of black currant (Ribes nigrum) cultivars. Significant enhancement of individual and total anthocyanins was measured after elicitation with MJ, particularly when a concentration of 0.2 mmol L(-1) was used. Total anthocyanins increased from 28288.74 ± 253.65 to 43561.08 ± 145.87 mg kg(-1) in Ben Hope black currants after elicitation with 0.2 mmol L(-1) MJ. Similarly, an increase from 35986.04 ± 287.98 to 41320.22 ± 109.38 mg kg(-1) was estimated in Ben Alder cultivar. Black currant flavonols were not individually affected by the treatment; however, total flavonols increased from 3115.21 ± 12.11 to 3268.41 ± 8.91 mg kg(-1) in Ben Hope and from 3016.38 ± 10.07 to 3110.95 ± 8.57 mg kg(-1) in Ben Alder. Antioxidant properties of black currants as measured by DPPH and ABTS assays improved proportionally to the increase in flavonoid content after MJ elicitation. Pre-harvest elicitation with MJ is proposed as a useful tool to enhance contents of anthocyanins and flavonols as well as free radical-scavenging activity of black currants. The functional black currants obtained here can be interesting for industry, for consumption as fresh fruits and for production of juice and jam. © 2015 Society of Chemical Industry.

Effects of pre-harvest methyl jasmonate treatment on post-harvest fruit quality of Japanese plums

Effects of pre-harvest methyl jasmonate treatment on post-harvest fruit quality of Japanese plums

Effects of Pre-Harvest Methyl Jasmonate Treatments on Bioactive Compounds and Peel Color Development of “Fuji” Apples

The present study was conducted to investigate the effects of pre-harvest methyl jasmonate treatments on peel color formation, total anthocyanin, total phenolics, total antioxidant capacity, and other selected fruit quality parameters of “Fuji” apples. Results revealed significant decreases in color parameters (L*, chroma, and hue values) with methyl jasmonate treatments. Total anthocyanin, total phenolics, and total antioxidant capacity of methyl jasmonate-treated fruits were significantly higher than control fruits. Methyl jasmonate concentrations increase linearly with increase in total anthocyanin, total phenolics, and total antioxidant capacity with high correlations. Ethylene synthesis-promoting impact of methyl jasmonate increased with increasing implementation doses. Methyl jasmonate treatments also increased fruit flesh firmness. While 1120 and 2240 mg/L methyl jasmonate treatments did not cause any significant changes in the starch degradation, 4480 mg/L methyl jasmonate treatment delayed the starch degradation. All methyl jasmonate treatments did not cause any or much significant changes in fruit mass, geometric mean diameter and soluble solids content of the fruits but yielded significant increase in titratable acidity values.

Variations in ellagic acid, quercetin and myricetin in berry cultivars after preharvest methyl jasmonate treatments

Effect of preharvest methyl jasmonate treatments on the levels of ellagic acid, quercetin and myricetin in raspberries and blackcurrants was investigated. Varietal influence on treatment effect was particularly considered. For this purpose, different cultivars of raspberry (Glen Lyon, Glen Ample and Tumaleen) and blackcurrant (Ben Hope, Ben Alder and Gairn) were studied. The treatments were carried out by spraying two distinct concentrations of methyl jasmonate (0.01 and 0.1mM) on berry plants. Cultivar to cultivar variations in the contents of ellagic acid and myricetin were observed in untreated berries. No varietal differences were however found in quercetin content. The effect of preharvest methyl jasmonate treatments was also cultivar independent. Preharvest methyl jasmonate always resulted in a general increase of the flavonoids studied, particularly, ellagic acid and quercetin. For instance, the content of ellagic acid increased approximately from 10 to 22mg100g−1 and quercetin increased from 6 to 16mg100g−1 in Glen Lyon raspberries. Similarly, ellagic acid increased from 6 to 11mg100g−1 and quercetin from 4 to 9mg100g−1 in Ben Hope blackcurrants. Preharvest methyl jasmonate treatment can be useful to food industry to obtain berries with enhanced health promoting properties.

EFFECTS OF PRE-HARVEST METHYL JASMONATE TREATMENT ON POST-HARVEST FRUIT QUALITY OF JAPANESE PLUMS

Background: Plum fruits constitute a good source of natural antioxidant substances. Particularly, plums contain large amounts of phenolic compounds and flavonoids having natural antioxidant activity which is effective in human diet. The aim of this study was to evaluate the effects of pre-harvest MeJA treatment on the fruit quality and bioactive compounds of three different Japanese plums under storage conditions.
 Materials and Methods: The effects of pre-harvest methyl jasmonate treatment (MeJA) on weight loss, color characteristics (L*, C* and h°), firmness, soluble solids content (SSC), titratable acidity (TA), total phenolics (TP) and total antioxidant activity (TAA) of ‘Black Beauty’, ‘Black Amber’ and ‘Fortune’ plum fruits during the cold storage (at 0±0.5 C and 90±5% RH) were investigated in this study. 
 Results: MeJA did not have significant effects on the weight loss (%) of ‘Black Amber’ and ‘Fortune’ fruits, whereas it was effective in delaying the weight loss of ‘Black Beauty’ at the end of storage. The color characteristics of all plum cultivars were not significantly affected by MeJA at the end of storage. In all plum cultivars, the SSC increased, while TA significantly (P

Effect of pre-harvest methyl jasmonate treatments on ethylene production, water-soluble phenolic compounds and fruit quality of Japanese plums.

The effects of pre-harvest methyl jasmonate (MJ) treatments on ethylene production, respiration rate, bioactive compounds and physico-chemical parameters of plum fruits (Prunus salicina Lindell cv. 'Fortune' and 'Friar') were investigated. Whole trees were sprayed once with an aqueous solution containing MJ (0, 1120 and 2240 mg L(-1)) 2 weeks before the anticipated commercial harvest for each cultivar. In both plum cultivars, 1120 mg L(-1) MJ significantly increased hue angle of fruits. The fruit mass and geometric mean diameter were lower in MJ treatments while flesh firmness was higher, except at initial harvest date. Soluble solids concentration increased and titratable acidity decreased with MJ treatments. MJ-treated fruits exhibited higher levels of ethylene production and respiration rate. MJ was more effective in increasing water-soluble antioxidant activity, water-soluble phenolics and individual phenolics. Chlorogenic acid, caffeic acid, rutin, ferulic acid, naringenin and kaempferol contents significantly increased with 2240 mg L(-1) MJ. This study revealed that pre-harvest MJ treatments were effective in delaying softening of late-harvested fruits and increasing bioactive compounds of plum fruits.

Methyl jasmonate treatments influence bioactive compounds and red peel color development of Braeburn apple

The present study was carried out to determine the effects of methyl jasmonate (MeJA) treatments on the fruit peel color parameters, anthocyanin content, ethylene biosynthesis, phenolic content, and antioxidant capacity of Braeburn apples. Experimental trees were treated with 1120, 2240, or 4480 mg L-1 MeJA at 1- and 2-week intervals between the 105th and 175th days of growth after full bloom. L* and hue decreased linearly with increasing MeJA concentrations in both experimental years. While MeJA treatments did not cause significant changes in chroma, except for in the final harvest in 2010, it decreased chroma values significantly on all sampling dates of 2011. Anthocyanin content, internal ethylene concentration, phenolic content, and antioxidant capacity increased linearly with increasing MeJA concentrations, regardless of the application interval: MeJA treatments with 1-week intervals were found to be as effective as those with 2-week intervals. Although MeJA treatments increased ethylene biosynthesis, they did not cause any softening; on the other hand, fruit firmness increased linearly with increasing MeJA concentrations. Preharvest MeJA treatments can be a good management strategy for red peel color development and fruit firmness preservation in Braeburn apples. Although both application regimes of MeJA significantly increased red color development, the treatments with 1-week intervals were found to be more effective than 2-week intervals with regard to phenolic content and antioxidant capacity.