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Age-dependent physiological responses of Corchorus olitorius to aqueous extracts of Murraya koenigii and Tithonia rotundifolia
61-66.Views:128Sustainable crop production increasingly utilizes allelopathic plants as sources of bioactive compounds, yet their bimodal inhibitory–stimulatory effects and oxidative mechanisms require further elucidation. This study investigated the concentration-, tissue-, and stage-dependent effects of aqueous shoot extracts from Murraya koenigii and Tithonia rotundifolia on the germination, growth, and oxidative defense of Corchorus olitorius. Seed emergence and elongation of radicles and plumules were monitored in the laboratory using 50% and 100% aqueous extracts, while potted seedlings were treated separately with 100% extracts. Laboratory bioassays demonstrated a dose-dependent response: a 50% M. koenigii extract transiently increased germination by 4%, while higher concentrations of both species inhibited germination by 7–25%. Juvenile growth inhibition was tissue-specific, with 100% M. koenigii primarily suppressing plumule elongation and 100% T. rotundifolia significantly reducing radicle growth. Conversely, pot experiments using 100% extract concentrations of both plants significantly enhanced vegetative growth, physiological traits, and biochemical constituents, including protein and ascorbic acid. These extracts bolstered the antioxidant defense system—increasing superoxide dismutase, catalase, and peroxidase activities—while markedly reducing malondialdehyde levels. These findings provide evidence of allelopathic hormesis, where initial inhibitory effects transition into growth stimulation and oxidative stress mitigation during later developmental stages. The results suggest that M. koenigii and T. rotundifolia shoot extracts serve as effective eco-friendly biostimulants that improve crop performance by modulating antioxidant responses.
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Varietal variations in fruit quality parameters in strawberry (Fragaria×ananassa) harvested at different stages of color development
102-114.Views:32Present investigation reports the fruit quality of five strawberry cultivars (‘Rania’, ‘Winter Dawn’, ‘Winter Star’, ‘Camarose’ and ‘Navelia’) harvested at different stages of color development. These cultivars showed significant variations in their chemical composition. The highest and significant values of fruit weight, hue angle and total sugars were recorded in ‘Winter Star’ cultivar at full red stage. Total phenolics and ascorbic acid content were higher in ‘Camarose’ as compared to other cultivars. These parameters and reducing sugar content in strawberry fruits showed a direct relationship with DPPH radical scavenging activity. ‘Winter Star’ exhibited highest anthocyanin content form 25% red to full ripe red stage of fruit color development with most intensive color. Total soluble sugars, reducing sugars, pH, °Brix values increased from green to full red stage whereas titratable acidity showed the reverse trend. These cultivars showed significant differences in their physicochemical and biochemical composition at different stages of ripening in agroclimatic conditions of Punjab area of northwest India.
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Interaction impact of drought stress, nutrient-deficient water, and seed-borne pathogen (Alternaria alternata) on germination and vigor of two tomato varietiesination and vigor of two tomato varieties
48-53.Views:342Tomato (Solanum lycopersicum) is considered one of the leading vegetable plants in the world. This study evaluated the germination and vigor capabilities of ‘Marmande’ and ‘Kecskeméti Jubileum’ varieties under different conditions, including drought stress, nutrient-deficient water, and the effect of seed-borne disease caused by Alternaria alternata when prime and non-prime with salicylic acid. The experiment was conducted in the laboratory in 2023 at Agricultural and Food Sciences and Environmental Management Faculty of University of Debrecen. Results indicated that the ‘Kecskeméti Jubileum’ variety exhibited a superior strength to ‘Marmande’ in the seedling’s dry weight, seedling growth rate, and vigor index under nutrient-deficient water. Nevertheless, when applying levels of drought, the ‘Marmande’ variety had a higher viability rate of 62.5% in comparison with another variety, and the germination rate of the two tomato varieties is at 85.5% in 5% concentration but decreased progressively when exposed to a higher drought concentration of 10%. When using 3 ml of salicylic acid during germination stages, the seedling vigor index of ‘Marmande’ shows a greater index at 165 compared to ‘Kecskeméti Jubileum’, just 108 under the infection of Alternaria alternata. The results of the examination of drought stress, and the effect of Alternaria alternata, one cause of seed-borne pathogens, showed that the percentage germination and vigor ability of the ‘Marmande’ variety performed better than ‘Kecskeméti Jubileum’ under the same conditions.
