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Plants produce several chemically diverse bioactive substances that may influence the growth and development of other organisms when released into the environment in a phenomenon called allelopathy. Several of these allelopathic species also have reported medicinal properties. In this study, the potential allelopathic effects of more than a hundred medicinal plants from Cambodia were tested using the dish pack method. The dish pack bioassay method specifically targets volatile allelochemicals. Twenty-five species were found to have significant inhibitory effects on lettuce radicle growth. Eleven different plant families, including Iridaceae (2), Apocynaceae (2), Poaceae (2), Sapindaceae, Araceae, Combretaceae, Orchidaceae, Clusiaceae, Zingiberaceae, Rutaceae and Asparagaceae had the plant species with high inhibitory effects. Allophyllus serrulatus had the highest growth inhibitory effect on lettuce radicles more than 60%, followed by Alocasia macrorrhiza, Iris pallida, Terminalia triptera, Wrightia tomentosa, Cymbidium aloifolium, Garcinia villersiana and Kaempferia parviflora. The candidate species were subjected to further studies to identify the volatile allelochemicals in the volatile constituents.
Yourk Sothearith; Kwame Sarpong Appiah; Hossein Mardani; Takashi Motobayashi; Suzuki Yoko; Khou Eang Hourt; Akifumi Sugiyama; Yoshiharu Fujii. Determination of the Allelopathic Potential of Cambodia’s Medicinal Plants Using the Dish Pack Method. Sustainability 2021, 13, 9062 .
AMA StyleYourk Sothearith, Kwame Sarpong Appiah, Hossein Mardani, Takashi Motobayashi, Suzuki Yoko, Khou Eang Hourt, Akifumi Sugiyama, Yoshiharu Fujii. Determination of the Allelopathic Potential of Cambodia’s Medicinal Plants Using the Dish Pack Method. Sustainability. 2021; 13 (16):9062.
Chicago/Turabian StyleYourk Sothearith; Kwame Sarpong Appiah; Hossein Mardani; Takashi Motobayashi; Suzuki Yoko; Khou Eang Hourt; Akifumi Sugiyama; Yoshiharu Fujii. 2021. "Determination of the Allelopathic Potential of Cambodia’s Medicinal Plants Using the Dish Pack Method." Sustainability 13, no. 16: 9062.
The continuous planting of Japanese pear leads to a soil sickness syndrome that eventually affects the growth and yield of the plant. In this study, we aimed to elucidate the characteristics of soil sickness syndrome in the Japanese pear and construct countermeasures using the rhizosphere soil assay method that can quantify the risk of soil sickness syndrome by inhibitory chemicals. Water flushing treatment, rainfall treatment, and the incorporation of test soils with different rates of activated carbon were evaluated on the risks of soil sickness. The water flushing treatment under laboratory conditions and exposure of the continuous cropping soil to rainfall in the open field decreased the inhibition rate of the soil. The decrease in soil inhibition rate was presumed to be the result of accumulated growth inhibitory substances in the soil being washed away by water. In addition, activated carbon with the potential to reduce the soil sickness syndrome was selected using the rhizosphere soil assay method. It was clarified that the mixing of the selected activated carbon with the continuous cropping soil reduced the inhibition rate and increased the growth of pear trees increased compared to the untreated soil from the continuous cropping field. The inhibition rate of the soil from the continuous cropping field was reduced to the level of soil with no history of Japanese pear cultivation. In the replanted field, these treatments can promote the growth of trees by reducing the influence of soil sickness syndrome.
Tomoaki Toya; Masayoshi Oshida; Tatsuya Minezaki; Akifumi Sugiyama; Kwame Appiah; Takashi Motobayashi; Yoshiharu Fujii. Elucidation of the Characteristics of Soil Sickness Syndrome in Japanese Pear and Construction of Countermeasures Using the Rhizosphere Soil Assay Method. Agronomy 2021, 11, 1468 .
AMA StyleTomoaki Toya, Masayoshi Oshida, Tatsuya Minezaki, Akifumi Sugiyama, Kwame Appiah, Takashi Motobayashi, Yoshiharu Fujii. Elucidation of the Characteristics of Soil Sickness Syndrome in Japanese Pear and Construction of Countermeasures Using the Rhizosphere Soil Assay Method. Agronomy. 2021; 11 (8):1468.
Chicago/Turabian StyleTomoaki Toya; Masayoshi Oshida; Tatsuya Minezaki; Akifumi Sugiyama; Kwame Appiah; Takashi Motobayashi; Yoshiharu Fujii. 2021. "Elucidation of the Characteristics of Soil Sickness Syndrome in Japanese Pear and Construction of Countermeasures Using the Rhizosphere Soil Assay Method." Agronomy 11, no. 8: 1468.
Phnom Kulen National Park, in north-western Cambodia, has huge richness in biodiversity and medicinal value. One hundred and ninety-five (195) medicinal plant species were collected from the national park to examine allelopathic potentials by using the sandwich method, a specific bioassay for the evaluation of leachates from plants. The study found 58 out of 195 medicinal plant species showed significant inhibitory effects on lettuce radicle elongation as evaluated by standard deviation variance based on the normal distribution. Three species including Iris pallida (4% of control), Parabarium micranthum (7.5% of control), and Peliosanthes teta (8.2% of control) showed strong inhibition of lettuce radicle elongation less than 10% of the control. The results presented could present as a benchmark for isolation and identification of allelochemicals among medicinal plants used in Cambodia.
Yourk Sothearith; Kwame Appiah; Takashi Motobayashi; Izumi Watanabe; Chan Somaly; Akifumi Sugiyama; Yoshiharu Fujii. Evaluation of Allelopathic Potentials from Medicinal Plant Species in Phnom Kulen National Park, Cambodia by the Sandwich Method. Sustainability 2020, 13, 264 .
AMA StyleYourk Sothearith, Kwame Appiah, Takashi Motobayashi, Izumi Watanabe, Chan Somaly, Akifumi Sugiyama, Yoshiharu Fujii. Evaluation of Allelopathic Potentials from Medicinal Plant Species in Phnom Kulen National Park, Cambodia by the Sandwich Method. Sustainability. 2020; 13 (1):264.
Chicago/Turabian StyleYourk Sothearith; Kwame Appiah; Takashi Motobayashi; Izumi Watanabe; Chan Somaly; Akifumi Sugiyama; Yoshiharu Fujii. 2020. "Evaluation of Allelopathic Potentials from Medicinal Plant Species in Phnom Kulen National Park, Cambodia by the Sandwich Method." Sustainability 13, no. 1: 264.
Weed management is an important issue since weeds directly compete with crop plants for space, nutrients; serve as habitat for insect pests and diseases, and can create a significant annual reduction in crop productivity. This study focused on evaluating the contribution of the secondary metabolites of the fruit pulp of Couroupita guianensis Aubl. for its potential growth inhibitory effect. Crude extracts of C. guianensis fruit pulp were collected with different solvents and applied to test plants in petri dishes. The crude extracts of methanol and 1% dimethyl sulfoxide (DMSO) showed potential growth inhibitions with the 50% effective concentration (EC50) of 223 and 229 µg/mL in the bioassay experiment. In the greenhouse pot experiment, soil incorporated with oven-dried fruit pulp of C. guianensis was evaluated on cultivated plant species including Lactuca sativa L., Trifolium repens L., Medicago sativa L., Lolium multiflorum Lam., and Phleum pratense L. The incorporation of dried fruit pulp of C. guianensis into soil reduced shoot and root lengths and the germination percentage of test plants. It was observed that the monocot plants were more affected than the dicot plants. The fruit pulp of C. guianensis was subjected to reversed-phase high-performance liquid chromatography (HPLC) analysis to identify the active compounds. Indigo, identified as one of the candidate compounds of the C. guianensis, had high specific activity (i.e., strong inhibitory activity) in a phytotoxicity bioassay and could explain through the total activity concept the growth inhibitory effect of the C. guianensis on test plants. The results suggested that indigo has plant growth inhibitory effect, indicating the allelopathic potential of C. guianensis, which could be exploited in sustainable weed management.
Kohinoor Begum; Takashi Motobayashi; Nazmul Hasan; Kwame Sarpong Appiah; Mashura Shammi; Yoshiharu Fujii. Indigo as a Plant Growth Inhibitory Chemical from the Fruit Pulp of Couroupita guianensis Aubl. Agronomy 2020, 10, 1388 .
AMA StyleKohinoor Begum, Takashi Motobayashi, Nazmul Hasan, Kwame Sarpong Appiah, Mashura Shammi, Yoshiharu Fujii. Indigo as a Plant Growth Inhibitory Chemical from the Fruit Pulp of Couroupita guianensis Aubl. Agronomy. 2020; 10 (9):1388.
Chicago/Turabian StyleKohinoor Begum; Takashi Motobayashi; Nazmul Hasan; Kwame Sarpong Appiah; Mashura Shammi; Yoshiharu Fujii. 2020. "Indigo as a Plant Growth Inhibitory Chemical from the Fruit Pulp of Couroupita guianensis Aubl." Agronomy 10, no. 9: 1388.
The paddy field is primarily used as an agricultural system to produce rice, which is the main staple food in Japan. The paddy field plays an important role in the various ecosystem functions such as flood control, groundwater recharge, improvement of water quality, local climate mitigation, fish culture and other non-rice productions, fostering culture and landscape, and maintaining biodiversity, among others. Paddy fields provide an important habitat to foster biodiversity. The remaining rice paddies in urban regions have an important role to alleviate the deterioration of the urban environment. In the first section, no-tillage cultivation studies carried out so far to investigate its effects on biodiversity in paddy fields are explained. Results show that spiders and carabid beetles prefer no-tillage soils in which the litter accumulate to the soil surface where abundant decomposers exist. Actually, in various types of crops, the density of soil-inhabiting predators such as spiders and carabid beetles is known to be higher in no-tillage or reduced-tillage cultivation field. The results also suggest that predation by spiders (especially lycosid spiders) is an important mortality factor for older larvae of the straight swift, and the effect is greater for the no-tillage paddy fields than the conventional paddy fields. In the following sections, an integrated rice farming method that uses crossbred ducks being practiced since 150 years ago, known as Aigamo farming in Japanese, is described. The rice-duck farming is a promising technique for producing organic rice in Southeast Asia. The farming system involves organic food certification systems, organic farmers’ cooperatives, community-wide organic farming, localized technical extension and educational services, and integration of farms and rice-duck. An experiment undertaken for the simultaneous cultivation of rice plants and baby crossbred ducks at the university farm in Fuchu, Tokyo, shows the effects of the release of crossbred ducks on the growth and quantities of rice plants, weeds, and diversity of the arthropod community.
Takashi Motobayashi; Seishu Tojo. Symbiotic Coexistence of Paddy Field and Urban Ecosystem. Recycle Based Organic Agriculture in a City 2019, 173 -202.
AMA StyleTakashi Motobayashi, Seishu Tojo. Symbiotic Coexistence of Paddy Field and Urban Ecosystem. Recycle Based Organic Agriculture in a City. 2019; ():173-202.
Chicago/Turabian StyleTakashi Motobayashi; Seishu Tojo. 2019. "Symbiotic Coexistence of Paddy Field and Urban Ecosystem." Recycle Based Organic Agriculture in a City , no. : 173-202.
The objective of this study is to assess the applicability of a commercial magnesium oxide (MgO) and a composite material containing MgO and natural minerals (‘MgO-SH-A’) as the soil amendments for suppression of cadmium (Cd) uptake and accumulation into rice grains. A cultivation experiment of rice plants (Oryza sativa L. cv. Kinuhikari) was conducted in an actual Cd-contaminated alluvial paddy field to evaluate the effectiveness of these materials. The ‘plant available’ fractions of Cd in the paddy soil significantly decreased by application of commercial MgO at 2250 kg ha−1 or MgO-SH-A at 4500 kg ha−1. These decreases would be primarily attributed to the increase in soil pH due to applications of the MgO materials because these soil Cd fractions were significantly negatively correlated with the soil pH. Even under a suppressive condition for Cd uptake by rice plants, i.e., continuous flooding of the paddy field around the heading stage, applications of these materials further reduced Cd concentration in brown rice as compared to that from the control. It was concluded that the two MgO materials examined would be effective in preventing Cd contamination of rice grains grown in Cd-polluted paddy fields.
Tetsuro Kikuchi; Masanori Okazaki; Sonoko Dorothea Kimura; Takashi Motobayashi; Jamsranjav Baasansuren; Takayuki Hattori; Toshio Abe. Suppressive effects of magnesium oxide materials on cadmium uptake and accumulation into rice grains: II: Suppression of cadmium uptake and accumulation into rice grains due to application of magnesium oxide materials. Journal of Hazardous Materials 2008, 154, 294 -299.
AMA StyleTetsuro Kikuchi, Masanori Okazaki, Sonoko Dorothea Kimura, Takashi Motobayashi, Jamsranjav Baasansuren, Takayuki Hattori, Toshio Abe. Suppressive effects of magnesium oxide materials on cadmium uptake and accumulation into rice grains: II: Suppression of cadmium uptake and accumulation into rice grains due to application of magnesium oxide materials. Journal of Hazardous Materials. 2008; 154 (1-3):294-299.
Chicago/Turabian StyleTetsuro Kikuchi; Masanori Okazaki; Sonoko Dorothea Kimura; Takashi Motobayashi; Jamsranjav Baasansuren; Takayuki Hattori; Toshio Abe. 2008. "Suppressive effects of magnesium oxide materials on cadmium uptake and accumulation into rice grains: II: Suppression of cadmium uptake and accumulation into rice grains due to application of magnesium oxide materials." Journal of Hazardous Materials 154, no. 1-3: 294-299.