Mitigation of the effect of drought on growth and yield of pomegranates by foliar spraying of different sizes of selenium nanoparticles.

BACKGROUND: Drought is a very important environmental stressor, which has negative effects on the growth of trees, decreasing their yield. The role of different-sized selenium nanoparticles (Se-NPs) in the mitigation of environmental stresses such as drought in crops has not yet been investigated. RESULTS: Trees treated with Se-NPs displayed higher levels of photosynthetic pigments, a better nutrient status, better physical parameters (especially fruit cracking) and chemical parameters, a higher phenolic content, and higher concentrations of osmolytes, antioxidant enzymes, and abscisic acid than untreated trees under drought stress. Foliar spraying of 10 and 50 nm Se-NPs alleviated many of the deleterious effects of drought in pomegranate leaves and fruits and this was achieved by reducing stress-induced lipid peroxidation and H2 O2 content by enhancing the activity of antioxidant enzymes. Furthermore, the 10 nm Se-NPs treatment produced more noticeable effects than the treatment with 50 nm Se-NPs. CONCLUSION: Results confirm the positive effects of nanoparticle spraying, especially the role of 10 nm Se-NPs in the management of negative effects of drought not only for pomegranates but potentially also for other crops. © 2021 Society of Chemical Industry.

Methyl jasmonate alleviates chilling injury and keeps intact pericarp structure of pomegranate during low temperature storage.

Pomegranate is a kind of fruit with low temperature sensitivity. Abnormal low temperature can easily lead to chilling injury, which negatively impacts the appearance of fruit, accelerates browning and deterioration, as well as seriously reduces the consumption quality and commodity value of pomegranate. This study was carried out to determine the effect of methyl jasmonate on chilling injury of pomegranate during low temperature storage. The result showed that methyl jasmonate treatment effectively maintained edible quality of pomegranate, suppressed the polyphenol oxidase activity and the development of chilling injury index, and inhibited the decline of total phenol content and the increase of malondialdehyde content and cell membrane permeability. In addition, methyl jasmonate could also enhance the disease resistance of fruit by increasing the content of soluble protein, and effectively maintain the integrity of epidermal cell structure and tissue structure. Overall, the conclusion of this paper is that methyl jasmonate can be used as an effective means to suppress chilling injury in postharvest storage of pomegranate.

[Protection by some plant methanol extracts of cherry tomatoes (Solanum lycopersicum var. Cerasiforme) from fungic infection by Alternaria alternata]. / Utilisation d'extraits méthanoliques de plantes pour la protection des cultures de tomates-cerises (Solanum lycopersicum var. cerasiforme) contre l'infection fongique par Alternaria alternata.

Cherry tomato is very susceptible to fungal infections that can cause considerable damage in crops and during storage. Alternaria infection is one of the most common and dangerous alterations for this fruit. They are caused by Alternaria alternata or some other species belonging to the same genus. In this work, we tested the antifungal activity of methanol extracts from five plants harvested in the region of Jijel (Algeria) on A. alternata. The activity was first tested in vitro and then on greenhouse cherry tomato plants: extracts were applied to healthy plants before infection in order to test their preventive action, and after infection to determine whether they are able to knock out Alternaria. Results showed that Rosmarinus officinalis and Lavandula angustifolia extracts were the most active in vitro on A. alternata. Microscopic observations of the mold indicated that these extracts inhibited the dictyospores production. The antifungal activity tested on the plants grown in greenhouse revealed that R. officinalis extract still was the most active. Extracts of L. angustifolia and Punica granatum did not protect the plants from Alternaria infection, but provided a total cure at the end of the treatment. Extracts from Quercus suber and Eucalyptus globulus were the least active. They did not bestow any protection nor complete healing of the plants. Dictyospores counting on fruits at the end of the treatment confirmed the results obtained for the greenhouse crops.

TITLE: Utilisation d'extraits méthanoliques de plantes pour la protection des cultures de tomates-cerises (Solanum lycopersicum var. cerasiforme) contre l'infection fongique par Alternaria alternata. ABSTRACT: La tomate-cerise est un fruit très sujet aux infections fongiques qui peuvent causer des dégâts considérables dans les cultures et lors de la conservation. Les alternarioses comptent parmi les altérations les plus répandues et dangereuses pour ce fruit. Elles sont causées par Alternaria alternata ou d'autres espèces appartenant au même genre. Dans ce travail, nous avons testé l'activité antifongique d'extraits méthanoliques de cinq plantes récoltées dans la région de Jijel (Algérie) sur A. alternata. L'activité a d'abord été testée in vitro, puis sur des plants de tomates-cerises cultivés sous serre : les extraits ont été appliqués sur des plants sains, avant l'infection, afin de tester leur action préventive, et après l'infection pour déterminer s'ils sont capables de traiter l'alternariose. Les résultats ont montré que les extraits de Rosmarinus officinalis et Lavandula angustifolia étaient les plus actifs in vitro sur A. alternata. L'observation microscopique de la moisissure a indiqué que ces extraits agissaient en inhibant sa production de dictyospores. L'activité antifongique testée sur les plants cultivés sous serre a révélé que l'extrait de R. officinalis était toujours le plus actif. Venaient ensuite les extraits de L. angustifolia et Punica granatum qui n'ont pas permis la protection des plants contre l'alternariose, mais qui ont néanmoins donné une guérison totale à la fin du traitement. Les extraits de Quercus suber et Eucalyptus globulus étaient les moins actifs. Ils n'ont permis ni la prévention, ni la guérison complète des plants. Le comptage des dictyospores réalisé sur les fruits à la fin du traitement a confirmé les résultats obtenus pour les cultures sous serre.

Chemopreventive effect of pomegranate and cocoa extracts on ultraviolet radiation-induced photocarcinogenesis in SKH-1 mice.

Non-melanoma skin cancer (NMSC) has a high and increasing incidence all over the world. Solar radiation is the main aetiology for humans. Although most research into photocarcinogenesis uses UVB as a source of radiation, UVA is also carcinogenic in long term. Pomegranate (PGE) and cocoa (CE) extracts have been used for medicinal purposes for time immemorial. Recently, it has been claimed that some of their properties may be an effective preventative measure against photocarcinogenesis and photoaging, but to date in vivo models have not been tested using RUVA, the objective of the present work. A lower incidence of lesions was observed in SKH-1 mice treated with PGE (p<0.001), and lower incidence of invasive squamous carcinoma in both treatment groups (p<0.001 for PGE and p<0.05 for CE); the PGE group also showed a lower level of cell proliferation than the control group (p<0.001). Significantly greater p53 alteration was observed in the control group than the treatment groups (p<0.001 for PGE and p = 0.05 for CE). No significant differences were found in relation to TIMP-1 and MMP-9. Taken together, the results suggest that oral feeding of PGE and CE to SKH-1 mice affords substantial protection against the adverse effects of RUVA, especially PGE.

Preharvest methyl jasmonate's impact on postharvest chilling sensitivity, antioxidant activity, and pomegranate fruit quality.

The fruit of pomegranate is bioactive compound source but is sensitive to low storage temperature. Methyl jasmonate (MeJA) spray on pomegranate trees was used in an attempt to evaluate its possible effect on fruit bioactive constituent changes and chilling injury (CI) incidence. Pomegranates trees were treated 15 days before harvest with distilled water or 1 and 2 mM MeJA, and then harvested fruit was stored at 4°C about 80 days. It was found that preharvest MeJA treatments improved arils color at harvest and reduced the postharvest CI index. Electrolyte leakage increased over storage, however, it was significantly higher in control rather than those treated. In addition, MeJA treatments significantly increased flavonoids, total antioxidant activity (TAA), total phenolics (TP), and total anthocyanins in comparison with untreated control. PRACTICAL APPLICATIONS: The demand for pomegranate fruit is rising because of its special taste and unique bioactive constituents. Therefore, find out methods to store it and deliver in expanded time has commercial value. The common method to extend food life is low temperature but pomegranate shows chilling evidence when stored at low temperature. Several methods have been used to alleviate chilling. In current study, methyl jasmonate was sprayed on tree and its possible effect on fruit that stored at low temperature was assessed. The results revealed that MeJA might have potential preharvest application to reduce chilling, retain the quality and nutrition value in pomegranate arils by affecting the antioxidant systems.