A novel edible coating based on Albizia [Albizia lebbeck (L.) Benth.] gum delays softening and maintains quality of harvested guava fruits during storage.

Guava, a commercially important fruit crop, is being grown in tropical and subtropical regions around the world. Due to the perishable nature of guava fruits, there are great losses during marketing, transport and storage. The application of edible coating is emerging as a low-cost, simple to implement and efficient method for extending the postharvest life of fresh horticultural produces, such as fruits and vegetables. This study aimed to assess the potential of Albizia gum (AZG) to improve storability and maintain the overall fruit quality of stored guava fruits. Freshly harvested guava fruits were coated with 0 % (control), 1.5 %, 3 % or 4.5 % AZG. After coating treatment, the fruits were stored at 20 ± 1 °C and 85-90 % relative humidity for 15 days. The results revealed that 4.5% AZG coating suppressed the weight loss and decay incidence up to 27 % and 36 %, respectively, as compared with control. The fruits coated with 4.5 % AZG had the maximum titratable acidity (0.40 %), ascorbic acid (104.47 mg·100 g-1), total antioxidants (118.84 mmol Trolox·100 g-1), total phenolics (285.57 mg·kg-1) and flavonoids (60.12 g·kg-1) on 15th day of storage. However, the minimum total soluble solids (11.97 %), sugar-acid ratio (29.31), relative ion leakage (68.40 %), malondialdehyde (0.11 nmol·kg-1 FW) and hydrogen peroxide (16.05 µmol·kg-1 FW) were recorded in the fruits of same treatment on 15th day of storage. Furthermore, the activities of antioxidant enzymes "i.e., superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX)" were increased under the influence of AZG coating. Consequently, as compared to uncoated fruits, AZG-coated fruits exhibited reduced activities of fruit softening enzymes "i.e., cellulase, pectin methylesterase (PME), and polygalacturonase (PG)". To sum up, the application of AZG-based edible coating could markedly improve the storage life of guavas and maintain overall fruit quality.

Vanadium toxicity was alleviated by supplementation of silicon in tomato seedlings: Upregulating antioxidative enzymes and glyoxalase system.

The primary goal of this research is to investigate the mitigating effect of silicon (Si; 2 mM) on the growth of tomato seedlings under vanadium (V; 40 mg) stress. V stress caused higher V uptake in leaf, and enhanced concentration of leaf anthocyanin, H2O2, O2•-, and MDA, but a decreased in plant biomass, root architecture system, leaf pigments content, mineral elements, and Fv/Fm (PSII maximum efficiency). Si application increased the concentrations of crucial antioxidant molecules such as AsA and GSH, as well as the action of key antioxidant enzymes comprising APX, GR, DHAR, and MDHAR. Importantly, oxidative damage was remarkably alleviated by upregulation of these antioxidant enzymes genes. Moreover, Si application enhanced the accumulation of secondary metabolites as well as the expression their related-genes, and these secondary metabolites may restricted the excessive accumulation of H2O2. In addition, Si rescued tomato plants against the damaging effects of MG by boosting the Gly enzymes activity. The results confirmed that spraying Si to plants might diminish the V accessibility to plants, along with promotion of V stress resistance.

Antifungal Potential of Indigenous Medicinal Plants against Myrothecium Leaf Spot of Bitter Gourd ( Momordica charantia L.)

ABSTRACT Bitter gourd is of great importance due to its usage against the treatment of numerous ailments in human beings. A comprehensive survey at four localities of Southern Punjab, Pakistan was carried out to determine the severity of Myrothecium leaf spot. Maximum disease severity was at C1 (Chak 11/NP) and least at C2 (Kot Mehtab). Among isolated species Myrothecium roridum was found more prevalent and pathogenic as compared to M. verrucaria. Antifungal activity using solvent extracts of five medicinal plants (Mangifera indica, Melia azedarach, Nicotiana tabacum, Moringa oleifera and Eucalyptus globosum) were evaluated against isolated species by agar well diffusion method at various concentrations (0.01, 0.10, 1.0 and 10.0 µg / mL). N. tabacum revealed maximum zone size (13.40 mm and 8.28 mm) with ethanol and chloroform solvents respectively followed by M. azedarach (9.00mm and 6.48mm). However, least inhibition was observed with ethanol and chloroform extracts of E. globosum (6.04mm and 3.88mm zone size respectively). Ethanol extracts showed highest activity when compared to chloroform extracts. Qualitative phytochemical analysis showed that all the selected plants are rich in chemical compounds such as alkaloids, terpenoids, flavonoids and phenols whereas Saponins was only present in N. tabacum while absent in rest of the extracts.