The maintenance of the quality and storage life of perishable fruits and vegetables is a major challenge for the food industry. In this study, the effects of different temperatures, packaging materials and storage time on the stability of capsaicinoids and antioxidants, such as total carotenoids, ascorbic acid and total phenolic compounds, were studied in three commercially cultivated hot pepper hybrids, namely Sky Red, Maha and Wonder King. For this purpose, dry whole pods were packed in jute bags and low-density polyethylene bags (LDPE), stored for five months under controlled conditions at 20, 25 or 30 ^○C and analyzed on Day 0 and at 50-day intervals until Day 150. The three hot pepper hybrids differed significantly with respect to their capsaicinoids and antioxidant concentrations, but the results indicated that with the increase in storage temperature and time, a gradual and steady decrease in these levels was equally observed for all hybrids. Overall, mean concentrations after five months were significantly reduced by 22.6% for ascorbic acid, 19.0% for phenolic compounds, 17% for carotenoids and 12.7% for capsaicinoids. The trends of capsaicinoids and antioxidants evolution were decreasing gradually during storage until Day 150, this effect being more pronounced at higher temperature. Furthermore, the disappearance rates of capsaicinoids and antioxidants were higher in peppers packed in jute bags than in those wrapped with LDPE. In conclusion, despite the sensitivity of capsaicinoids and antioxidants to oxygen, light and moisture, the packaging in natural jute or synthetic LDPE plastic bags, as well as the storage at ambient temperature preserved between 77.4% and 87.3% of the initial amounts of these health- and nutrition-promoting compounds during five months’ storage.

Early season carrot (Daucus carota) production is being practiced in Punjab, Pakistan to meet the market demand but high temperature hampers the seed germination and seedling establishment which cause marked yield reduction. Seed priming with potassium nitrate breaks the seed dormancy and improves the seed germination and seedling growth potential but effects vary among the species and ecological conditions. The mechanism of KNO₃ priming in high temperature stress tolerance is poorly understood yet. Thus, present study aimed to evaluate high temperature stress tolerance potential of carrot seeds primed with potassium nitrate and impacts on growth, physiological, and antioxidant defense systems. Carrot seeds of a local cultivar (T-29) were primed with various concentration of KNO₃ (T₀: unprimed (negative control), T₁: hydroprimed (positive control), T₂: 50 mM, T₃:100mM, T₄: 150 mM, T₅: 200 mM, T₆: 250 mM and T₇: 300 mM) for 12 h each in darkness at 20 ± 2℃. Seed priming with 50 mM of KNO₃ significantly enhanced the seed germination (36%), seedling growth (28%) with maximum seedling vigor (55%) and also exhibited 16.75% more carrot root biomass under high temperature stress as compared to respective control. Moreover, enzymatic activities including peroxidase, catalase, superoxidase dismutase, total phenolic contents, total antioxidants contents and physiological responses of plants were also improved in response to seed priming under high temperature stress. By increasing the level of KNO₃, seed germination, growth and root biomass were reduced. These findings suggest that seed priming with 50 mM of KNO₃ can be an effective strategy to improve germination, growth and yield of carrot cultivar (T-29) under high temperature stress in early cropping. This study also proposes that KNO₃ may induces the stress memory by heritable modulations in chromosomal structure and methylation and acetylation of histones that may upregulate the hormonal and antioxidant activities to enhance the stress tolerance in plants.

Carrot (Daucus carota L.) seed quality is affected by umbel position due to uneven maturation of carrot seeds produced in different umbel orders. However, keeping this in view, we tested whether seed quality could be improved with the suppression of tertiary umbels under exogenous auxin application. Using auxin-producing bacterial isolates, i.e., Bacillus sp. MN54, Enterobacter sp. MN17, Pantoea sp. MN34, and Burkholderia phytofirmans PsJN, the arrangements of carrot umbel order were evaluated in terms of quality carrot seed production. The results revealed that auxin production by plant-growth-promoting rhizobacteria showed significant differences among measured growth indices, yield, and seed quality attributes. The selected endophytic strains co-applied with auxin via foliar application improved all growth- and yield-related traits, as well as the enzymatic activities of carrots. Noticeably, MN17+L-tryptophan and MN34+L-tryptophan effectively minimized the number of tertiary umbels by increasing the number of secondary umbels. Furthermore, treating with PsJN+L-tryptophan and MN34+L-tryptophan resulted in reduced conductivity of seed leachates and malondialdehyde levels in primary, secondary, and tertiary umbel seeds. These findings collectively indicate the potential of the foliar application of PsJN+L-tryptophan and MN34+L-tryptophan to effectively alter umbel arrangement, leading to improved yield and seed quality. This study implies that carrot seed producers can consider employing specific PGPB strains, particularly MN34+L-tryptophan, to suppress tertiary umbels and achieve higher yields of high-quality carrot seeds.

Tri-genomic Brassica napus L.wasdeveloped by the cross between Brassica napusand Brassica nigra. The crop is animportant source of vegetable seed oil in Pakistan,after cotton. The low oilseed rape yield is attributed to high temperature in the production zones. Interspecific hybridization using these two speciescan be helpful to produce heat resistant hybrids. On the other hand, it has been found that foliar application of different plant growth regulators can be used to reduce the heat stress in Brassica. The objectiveof this studywas to test the response of three different tri-genomic hybrids to high temperature stressat seedling stage. Seedlings were foliar sprayed with 0.13 mM salicylic acid (SA) prior to exposure tohigh temperatureat two true leaf stage. The plants were harvested after 30 days of sowing for growth and biochemical analysis. Plants ofV38 showed the highest values for all morphological traits and biochemical activities among the threehybrids. In general, plants exposed to the temperature stress exhibited a significant decline in growth, chlorophyll content and enzyme activity.Foliar application of SA significantly improved leaf and root biomass under heat stress.Further, antioxidativeenzyme activities significantly increased in response to SA either compared to control or to plants exposed to temperature stress.It is concluded thatapplication of salicylic acid elevated activity of antioxidative enzymes and was helpful in mitigating the detrimental effects of high temperature inoil seed rape.

Oxidative stress is a key cause of gastrointestinal disorders, primarily stomach ulcers. Multiple intrinsic and extrinsic mechanisms caused the body to produce reactive oxygen species (ROS). The body's antioxidant defense system protects against these reactive species. When the degree of ROS production exceeds the normal range, the body's natural defense system fails to neutralize these dangerous free radicals, necessitating need foran exogenous source of natural antioxidants. Natural herbal remedies have been widely employed as antioxidants to relieve oxidative stress in gastric ulcers. Polyphenols, tannins, essential oils, flavonoids, notably quercetin, carotenoids, vitamin C, vitamin A, and minerals are among the molecules of immense interest in bioassays due to their significant antioxidant effects. In the present review, several natural anti-ulcer medicinal plants along with their antioxidative mechanism have been reported. Electronic databases including PubMed, Google Scholar and Scopus were explored to identify the antioxidant and gastroprotective potential of all the plants.