Nutrients and plant hormone are very essential and play a key role in drought stress tolerance. The current studies was conducted in pots, to investigate the role of potassium, zinc and gibberellic acid in biosynthesis of free proline, total phenolic, antioxidant compounds and drought stress tolerance in sunflower varieties. Plants were grown in glass house and foliar sprays of potassium Nitrate (KNO 3), zinc sulphate (ZnSO 4) and gibberellic acid GA 3 were applied. Varieties were evaluated for drought tolerance through leaf disc assay and polyethylene glycol PEG6000 was used to induce in-vitro drought stress. Zinc significantly increased the RWC% and maximum value was noted in HS-K6 followed by Rising Sun. Potassium increased the relative water content (RWC %) and the highest RWC % was found in Hysun-33 followed by Rising Sun, SMH-0907 and US-444. The biosynthesis of free Proline and total phenolic contents was significantly increased with Zn and K treatments. Superoxide dismutase, catalase, ascorbate peroxidase and ascorbic acid biosynthesis were significantly increased by Zn followed by potassium. The Zn treatment significantly reduced the MDA content in sunflower varieties. A significant positive correlation was found between RWC % with proline (R 2 = 0.92 ***) and total phenolic (R 2 = 0.95 ***) respectively. Antioxidant compounds also showed significant positive correlation with relative water content. Conclusively; drought tolerance in sunflower might be increased by foliar application of Zn, K and GA 3. Further investigation is suggested to study the effect of Zn, K and GA 3 on drought tolerant genes expression.

The apple is the most widely used fruit globally. Apples are more prone to fungal spoilage, which leads to browning and subsequent changes in their flavor and texture. Browning is also caused by the tyrosinase enzyme. By inhibiting tyrosinase initiation and fungal spoilage in fruits, the natural flavor and texture of fruits can be maintained. Biogenic NPs can act as antioxidants to inhibit tyrosinase and due to oxidative stress, it also catalyzes the deformation of fungal hyphae and spores. Nanotechnology is a research hotspot that has gained considerable interest due to its potential inferences in biosciences and food preservation technology. The present study aims to use biomass from the Fagonia cretica to create bio-inspired manganese oxide MnO2 NPs and to evaluate its bio-catalytic potential for antifungal anti-browning through the inhibition of tyrosinase and its antioxidant potential for preserving apple flavor and texture. The green synthesized nanoparticles were extensively analyzed using UV spectroscopy, XRD, SEM, EDX, and FTIR techniques. Moreover, the synthesized manganese oxide nanoparticles (MnO2 NPs) were evaluated for their bio-catalytic potential as anti-fungal and anti-spoiling agents. The values of antifungal activity among all the samples were 14.2 ± 86 mm, 8.9 ± 6.0 mm, 17.7 ± 1.26, and 20.7 ± 4.38 mm for Penicillium expansum, Monilinia fructigena, Penicillium chrysogenum, and Aspergillus oryzae at 200 µg/well, respectively. Moreover, the biogenic NPs were evaluated for their anti-browning potential through the inhibition of tyrosinase. MnO2 NPs have been shown to have considerable inhibitory effects on tyrosinase up to 64.8 ± 0.16 at 200 µg/mL and (27.2 ± 0.58) at 25 µg/mL. Biogenic MnO2 NPs can also act as antioxidants to inhibit tyrosinase and fungal growth by the formation of free radicals that damage the fungal hyphae and, as a result, slow down browning. The maximum DPPH free radical scavenging activity was 74.5 ± 0.39% at 200 µg/mL, and the minimum was 12.4 ± 0.27 at 25 µg/mL. The biogenic MnO2 NPs are biocompatible and play a potent role in maintaining the flavor and texture of apples.

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Boswellia sacra is an economically important species of family Burseraceae used for frankincense production, an aromatic bark resin that has been a product of local and global trade since prehistoric times in Oman. To help conservation efforts for Boswellia sacra populations from Oman, we evaluated 13 populations from diverse ecological locations based on RAPD and SDS-PAGE genetic markers. Genetic diversity based information and the pattern of genetic differentiation across the species habitats helps strategies to conserve wild genetic resources. This is the first in Oman on the genetic evaluation of Boswellia sacra populations based on total leaves protein and RAPD analysis. RAPD primers produced a total of 40 RAPD fragments, of which 34 (85%) were polymorphic. Each primer generated 7 to 9 bands with an average of 8 bands per primer. Total leaves protein revealed total 12 polypeptides bands of which 4 (33%) were polymorphic (ranging from 20 to 72 KDa). The levels of expected heterozygosity for RAPD and SDS-PAGE markers were 0.288 and 0.122 respectively. AMOVA analysis showed high level of molecular variance within populations (RAPD-68% and SDS PAGE-81%) and low level molecular variance among populations. Isolation by distance model revealed no significant correlation between genetic distances and geographic distances. UPGMA-cluster analysis grouped majority of the populations in the same cluster but some showed high genetic and geographic distances from central and western regions (Thumriat, Dowkha and Mughsil). The results conclude that at present high level of genetic diversity is still preserved in B. sacra populations in Dhofar regions.