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    Changes in the activity of enzymes associated with enzymatic browning and chemical composition during Musa sapientum Linn. 'Kluai Khai' banana fruit ripening
    (2023-07-01)
    Makboriboon, N.
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    The results showed that the initial firmness of banana fruit harvested at the raw stage was 7 N and decreased to less than 2 N at overripe and very ripe stages. The total soluble solids increased throughout the ripening period, whereas the titratable acidity maintained a high level during the ripening process. The banana peel stayed green during the raw stage, and the yellow color formed between the unripe stage to the overripe stage. The lightness of the banana peel increased from the raw stage to the ripe stage, decreased at the overripe stage, and then dropped sharply at the very ripe stage. This color change was linked to the browning incidence of the fruit peel and an increasing browning area and soluble browning pigment content. The PPO and POD showed a low activity at the raw stage and then increased with advancing ripening and maintained a significantly higher level than the raw fruit. The findings of this study exhibited that the ripening stages of the 'Kluai Khai' banana influence the firmness, peel color, and browning incidence of the fruit peel and the polyphenol oxidase and peroxidase activities.
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    Characterization of Diaporthe fungal extract composition and phytotoxicity on the aquatic noxious weed Eichhornia crassipes: inhibitory effects on photosynthetic machinery and membrane integrity
    (2025-01-01) ;
    Manichart, Nutcha
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    Thongbang, Muanfan
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    Wichittrakarn, Pattharin
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    Fungal extract-based natural herbicides are a promising avenue for the development of sustainable weed management. The study investigates the herbicidal activity of fungal extracts against the prominent aquatic invasive weed Eichhornia crassipes (water hyacinth). The ethanol crude fraction derived from Diaporthe sp. strain EC010 demonstrated the highest phytotoxicity. Chemical characterization using gas chromatography-mass spectrometry revealed 2(3H)-furanone, dihydro-4-hydroxy- (22.81%), linoelaidic acid (6.87%), and hordenine (6.62%) as major constituents. Phytotoxicity was evaluated by wrapping bioassay under greenhouse conditions. Observable foliar damage, such as necrosis, chlorosis, and depigmentation, occurred within 1 day after treatment (DAT). The rapid onset of visible damage within 1 DAT and the detailed analysis of tissue damage are particularly noteworthy. Lesion progression reflected the phytotoxicity of the extract, increasing to 77.33% visible phytotoxicity at 14 DAT for the highest concentration (8.0% w/v). Microscopic analysis revealed disintegration and complete deformation of epidermal and parenchymal tissues, and treated plants featured extensive aerenchyma spaces. Furthermore, the Diaporthe sp. extract decreased chlorophyll a, b, and carotenoid concentrations while increasing electrolyte leakage and malondialdehyde, indicative of weed deterioration. The current work offers valuable insights for sustainable and eco-friendly strategies in the management of water hyacinth populations in a lentic ecosystem. The findings suggest that Diaporthe sp. extract could serve as a natural herbicide, offering an environmentally friendly alternative to synthetic chemicals in managing water hyacinth.
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    Induced mutation of curcuma hybrid cv. sweetmemory through tissue culture by ethyl methanesulphonate (EMS)
    (2025-01-01)
    Yoosumran, V.
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    Ruamrungsri, S.
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    Akarapisarn, A.
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    The ethyl methanesulphonate (EMS) is induced mutation in Curcuma hybrid cv. sweetmemory. The shoot size 1 cm were cultured on Murashige and Skoog medium (MS) supplemented with 2 mg/l BA for plantlet induction. After 8 weeks of culture, it was observed that the shoots soaked in 0% EMS at 60 and 120 minutes survived 100%. In additions it was found the highest percentage of shoot emergence, number of shoots, and plant height. While plants treated with EMS solution had decreased survival and growth rates. Thereafter, existing plantlets were potted, and growth was observed. It turned out that the plants none receiving EMS solution (control) had the survival rate and growth rate were better than those of the plants receiving EMS solution. Results showed that control plants receiving 0% EMS at 60 minutes gave highest content of chlorophyll a as 4.06 µg/cm<sup>2</sup>, chlorophyll b of 2.08 µg/cm<sup>2</sup> and carotenoid of 3.09 µg/cm<sup>2</sup> but there was none statistical difference with the plants that received EMS solution. The control plants had larger stomata sizes than those that received the EMS solution. However, there was no difference in the number of chloroplasts among treatments. The living plantlets from all treatments were tested Random amplified polymorphic DNA (RAPD) marker and genomic DNA was extracted from fresh leaves. A dendrogram was constructed polymorphic bands using the NTSYSpc program (version 2.10p) showing 2 clusters which separated with similarity coefficients ranging from 0.74-1.00.
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    Siamese neem tree as a natural preservative: Chemical profile, antioxidant properties, and antibacterial efficacy against foodborne pathogens and spoilage bacteria
    (2025-03-01) ;
    Manichart, Nutcha
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    The objective of the present study was to investigate the effect of various ethanol in water solvent systems (0, 25, 50, 75 and 100 % v/v) on the extraction crude yield, total phenolic content, total flavonoid content, and chemical profile of Azadirachta indica (Siamese neem tree) leaf extracts. In addition, the antioxidant and antimicrobial properties were investigated using in vitro assays. Crude yield was highest for the water extract (5.78 g/100 g DW) and decreased with increased ethanol. Total phenolic and flavonoid contents were highest in the 75 % ethanol extract (26.95 mg GAE/g crude and 23.73 mg QE/g crude, respectively). GC-MS analysis of the 75 % ethanol extract revealed 33 bioactive compounds, accounting for 96.33 % of the total area. Significant components included benzene, 1,4-bis(phenylmethyl)- (15.05 %), and naphthalene, 1,6-dimethyl- (10.98 %); also present were sterols, fatty acids, hydrocarbons, aromatic, and heterocyclic compounds, indicating a complex chemical profile. In antioxidant assays, the 75 % ethanol extract revealed the highest DPPH radical scavenging activity (IC<inf>50</inf>: 143.03 mg/L), reducing power (IC<inf>50</inf>: 378.69 mg/L), and lipid peroxidation (IC<inf>50</inf>: 526.25 mg/L). However, the absolute ethanol extract exhibited both the highest metal chelating activity (IC<inf>50</inf>: 382.60 mg/L) and the strongest antimicrobial activity, inhibiting all 11 tested foodborne pathogenic and spoilage bacteria. The lowest minimum inhibitory concentration (MIC) of 25 mg/mL was observed for Staphylococcus aureus, Aeromonas hydrophila, Pseudomonas fluorescens, Latilactobacillus sakei, Streptococcus sp., and Lactococcus cremoris, with inhibition zone diameters of 27.21, 28.79, 28.19, 17.60, 15.09 and 11.20 mm, respectively. Similarly, the lowest minimum bactericidal concentration (MBC) of 25 mg/mL was obtained for S. aureus and L. sakei, indicating potent antibacterial effects against these species. Future studies should include direct comparative analyses of neem extracts and synthetic preservatives to evaluate further their relative efficacy and applicability in real-world food systems.
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    The effect of BA on inducing shoots of Philodendron erubescent 'Pink Princes' in vitro
    (2023-11-01)
    Chiewchan, N.
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    The study investigated the influence of plant growth regulator on the induction of direct shoots from node explants of Philodendron erubescens 'Pink Princes' in vitro condition. The result showed that the most of width, length, and height was observed in MS + BA 0.5 mg/l, measuring 3.40 cm × 3.22 cm × 1.96 cm and 1.74 g fresh weight. The highest number of shoots was consistently observed 60.44 shoots per nodal MDA content (1.91 nmol/g FW) and phenolic content (9.51 mg GAE/g FW) are lowest. The explant was cultured on MS medium performed highest chlorophyll content (chl A 213.96 μg/g FW, chl B 162.54 μg/ FW, total chlorophyll 304.64 μg/FW) and carotenoid content (2.61 μg/g FW) Moreover, they were the largest plant with green leaves when compared to another treatment.
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    Oxidative damage in Echinochloa crus−galli seeds exposed to Diaporthe sp. (Diaporthales, Ascomycota) fungal extract during germination
    (2024-01-01) ;
    Manichart, Nutcha
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    Wichittrakarn, Pattharin
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    Yoneyama, Kaori
    This study investigates the inhibitory effects of Diaporthe sp. isolate EC010 extract on barnyardgrass (Echinochloa crus-galli) seed germination and growth. Application of sequential extraction techniques to Diaporthe sp. mycelium resulted in partial separation of the phytotoxic compounds. The ethyl acetate (EtOAc) fraction most greatly reduced seed germination (81.01%), root length (89.18%), and shoot length (84.74%) compared to the control. Chemical characterization using gas chromatography-mass spectrometry revealed major constituents of linoleic acid, butyl ester (9.69%), hexadecanoic acid (7.99%), and 14-pentadecenoic acid (7.86%). With regard to physiological and biochemical indexes, treated seeds exhibited lower imbibition, significantly decreased α-amylase (EC 3.2.1.1) activity (p<0.05), and increased accumulation of malondialdehyde (85.52%) and hydrogen peroxide (141.10%). Moreover, activity of the antioxidant enzymes superoxide dismutase (EC 1.15.1.1) and guaiacol peroxidase (EC 1.11.1.7) was upregulated (67.24 and 61.62%, respectively), while catalase (EC 1.11.1.6) activity was downregulated (-33.75%). The inference is that an imbalance in ROS levels combined with reduced antioxidant potential drives the gradual accumulation of oxidative damage in seed cells and consequent loss of seed viability. All told, these results confirm the Diaporthe extract to induce oxidative stress and inhibit antioxidant enzymes. This study clearly demonstrates the oxidative damage associated with Diaporthe allelochemicals.
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    Lotus flower extract as a natural anti-browning agent for fresh romaine lettuce (Lactuca sativa L. var. longifolia)
    (2023-11-01)
    Pradabkun, N.
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    Yeamsuriyotai, K.
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    The effect of lotus (Nelumbo nucifera Gaertn.), butterfly pea (Clitoria ternatea) and Siam tulip (Curcuma sessilis) aqueous extract on reduction of polyphenol oxidase (PPO) and peroxidase (POD) in romaine lettuce (Lactuca sativa L. var. longifolia) were evaluated. Results showed that in vitro lotus flower aqueous extract exerted the highest reduction of PPO and POD activities on the romaine lettuce. The effectiveness of in vivo application of lotus flower aqueous extract to control browning cut stem ends of fresh romaine was examined. Romaine lettuce harvested as a whole plant and cut off at the stem. Cut stem ends of romaine lettuce were dipped in various concentrations of lotus flower extract for 5 min and packaged in polypropylene plastic bags. Weight loss, color, browning index as well as PPO and POD activities were evaluated during 12 days of storage at temperature of 10±2°C and relative humidity 50±5%. Cut stem ends dipped in 0.5% aqueous extract of lotus flower resulted in inhibition of browning of cut stem ends and decrease in PPO and POD activities. Thus, exogenous 0.5% aqueous lotus flower extract treatment could be a useful application to alleviate browning in cut stem ends of fresh romaine lettuce.
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    Impact of Nigrospora oryzae-Derived Natural Products on Photosynthesis and Oxidative Stress in Eichhornia crassipes
    (2025-01-01) ;
    Manichart, Nutcha
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    Wichittrakarn, Pattharin
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    Yoneyama, Kaori
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    Interest in natural herbicides has been growing due to government policies restricting synthetic herbicide use in many countries. In that regard, this study investigates the potential of Nigrospora oryzae extract as a natural herbicide against the aquatic invasive weed Eichhornia crassipes. A stable formulation was developed with a droplet size of 36.44 ± 0.36 nm and a zeta potential of -62.59 mV. Pot-based experiments revealed the N. oryzae extract induced 38.33% phytotoxicity within 24 hours, increasing to 84.72% by 28 days post-treatment. Scanning electron microscopy demonstrated morphoanatomical changes in epidermal tissue and stroma of E. crassipes, such as erosion of epicuticular waxes and degeneration of epidermis cells. The treatment significantly reduced the photosynthetic pigment content while increasing hydrogen peroxide (46.26%), malondialdehyde (17.49%), and proline (19.16%) levels, causing cellular electrolyte leakage. Activities of superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidase were significantly elevated (p<0.05), indicating oxidative damage. These findings demonstrate that N. oryzae extract can disrupt growth and photosynthesis and induce oxidative stress in E. crassipes, suggesting its potential as a source of natural herbicide for industrial application.
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    Effect of peppermint essential oil fumigation on seed quality of green soybean cultivar KPS292 after storage
    (2023-02-01)
    Yonsawad, N.
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    Seed storage conditions can determine germination characteristics and vigor potential of seeds. The present study aimed to test the effect of different storage conditions on seed germination in green soybean (Glycine max [L.] Merr.) 'KPS292'. Five methods of green soybean seed storage were examined: (1) untreated seeds were kept in refrigerator at 4°C (controlled conditions), (2) seeds fumigated with peppermint essential oil were kept in vacuum packed bags or (3) plastic boxes at room temperature, and (4) seeds fumigated with distilled water were kept in vacuum packed bags or (5) plastic boxes at room temperature. Results indicate that seeds stored at 4°C for six months exhibited the highest seed germination rates. No significant difference in germination rates of fumigation with the peppermint essential oil and kept in vacuum packed bag and fumigation with the peppermint essential oil and stored in plastic box was found compared to seed storage at 4°C. In addition, seed storage at 4°C showed the lowest electrolyte leakage from seeds, which did not differ from seeds fumigated with the peppermint essential oil that were kept in a vacuum-packed bag. For 12-month seed storage, all seed storage methods showed seed germination rates of <50%. Growth characteristics and yield performances were also determined under field conditions. All seed storage methods had no significant effects on plant height. Seed storage methods at 4°C, fumigation with the peppermint essential oil and kept in vacuum packed bag, and fumigation with the peppermint essential oil and stored in plastic box showed similar effects on plant height, plant biomass, node number per plant, pod number per plant, and seed yield per plant. On the other hand, the yield of seeds stored in plastic boxes was found to have decreased.
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    Improving Pepper Inbreds for Resistance to Pepper Yellow Leaf Curl Thailand Virus (PepYLCTHV) through Challenged Inoculations
    (2024-09-01)
    Kumsee, Nattika
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    Tsai, Wen Shi
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    Techawongstien, Suchila
    Chili peppers (Capsicum annuum L.) are an economically important crop worldwide. Pepper yellow leaf curl Thailand virus (PepYLCTHV), a Begomovirus causing yellow leaf mosaic disease of chili pepper, has been reported to incur 95% economic loss under epiphytotic conditions. Thirty-one chili genotypes were screened for resistance to PepYLCTHV disease through inoculation using 10–15 viruliferous whiteflies per plant. We purified two resistant lines (PEP6 and PEP12) through four generations of selfing and selection. At 28 days after inoculations, two chili genotypes (PEP6 and PEP12) had low disease severity and percentage of disease incidence (DI) compared to four susceptible checks, viz., Yodsonkeam80, Homsupan, Huareau12, and Pong Charian, which had a disease severity score of 5 with 100% DI. Thirty initial plants of PEP6 showed an average disease severity of 3.64 with 69.33% DI, and PEP12 showed an average disease severity of 3.83 with 77.67% DI. From these populations, we selected nine highly resistant plant of PEP6 and seven plants of PEP12 having a disease severity of 0 through pure-line selection for four selfing generations. The ratio of resistance (R) to susceptibility (S) consequently decreased. In PEP6, the ratio decreased from 1R:2S to 1R:1S, while in PEP12 the ratio decreased from 1R:3S to 1R:1S. These lines have potential for release as resistant lines for improving chili pepper resistance to PepYLCTHV and for developing makers associated with the resistant trait.