Plant growth inhibitory activity and active substances with allelopathic potential of cogongrass (Imperata cylindrica) rhizome

Cogongrass (Imperata cylindrica [L.] Raeusch.) is a perennial rhizomatous grass that belongs to the Poaceae and is widely distributed in tropical, subtropical and temperate regions over the world. The grass is strongly invasive and is suggested to have allelopathic potential. However, limited information is available on allelopathic substances in cogongrass rhizomes. Therefore, the allelopathic potential and substances in cogongrass rhizomes were investigated. The extracts of cogongrass rhizomes inhibited the root and shoot growth of barnyard grass, ryegrass, timothy, cress, lettuce and alfalfa. After bioassay‐guided separations of the extracts, four growth inhibitory substances, 5‐methoxyflavone, 5,2′‐dimethoxyflavone, methyl caffeate and abscisic acid, were isolated. 5‐Methoxyflavone, 5,2′‐dimethoxyflavone and methyl caffeate significantly inhibited the root and shoot growth of cress at concentrations of ≥0.03–0.3 m mol L^?1 and their concentrations required for 50% growth inhibition were 0.079–0.24, 0.23–1.1 and 0.59–0.88 m mol L^?1, respectively. The other isolated substance, abscisic acid, has been reported to have strong growth inhibitory activity. Its concentrations required for 50% growth inhibition on cress were 0.31–0.61 μ mol L^?1. The present study suggests that cogongrass rhizomes might have allelopathic potential and that those four substances might contribute to that potential.     

Diversity and community structure of wood-inhabiting fungi found in Japanese wooden houses analyzed by the next-generation sequencing

The diversity and community structures of wood-inhabiting fungi in 16 decayed wood samples from ten wooden houses in Japan were analyzed using a next-generation sequencing (NGS) to determine the fungi responsible for wood decay. DNA of fungi in decayed wood was extracted directly, the internal transcribed spacer (ITS) region in ribosomal DNA (rDNA) was amplified by polymerase chain reaction (PCR), and then, sequences of tagged ITS fragments were analyzed by NGS. Results of sequencing indicated that 68 species of ascomycetes, 37 species of basidiomycetes, and one fungus each from Mortierellales and Mucoromycetes were detected. The fungal community structures showed diversity and included various species of ascomycetes. A microscopic examination of cell wall structure in decayed wood samples suggested that some ascomycetes were soft-rot fungi. Heat map analysis indicated that the similarity in the structures of fungal communities was influenced to a greater extent by the wood species of samples than where they were used as a component.     

Necessity of dietary taurine supplementation for preventing green liver symptom and improving growth performance in yearling red sea bream Pagrus major fed nonfishmeal diets based on soy protein concentrate

The necessity of dietary taurine supplementation for preventing green liver symptom and improving growth performance of red sea bream Pagrus major fed nonfishmeal (non-FM) diets was investigated. Yearling red sea bream (initial body weight, 580 g) were fed for 36 weeks on non-FM diets based on soy protein concentrate (SPC) supplemented with taurine at levels of 0%, 0.5%, 1.0%, 1.5%, and 2.0%. Specific growth rate (SGR) and feed conversion ratio (FCR) of fish fed the taurine-unsupplemented SPC diet were markedly inferior. In these fish, incidence of green liver was markedly higher and was accompanied by a decrease of tissue taurine concentration and an increase of hepatopancreatic bile pigment content. The green liver symptom was mainly caused by an increase of hemolysis since the erythrocytes became osmotically fragile due to taurine deficiency. Physiological abnormality and growth performance (SGR and FCR) were markedly improved by taurine supplementation to the SPC diets. These results indicate that dietary taurine supplementation is necessary for yearling red sea bream fed non-FM diet based on SPC to maintain normal physiological condition and growth performance.     

Measurements of the bioelectrical potential of a Japanese oak (Quercus crispula Blume) sapling: Effect of the radial distribution of inorganic ingredients within a tree stem on the diurnal change in resting potential

This study investigated the relation between the resting potential of a 2-year-old Japanese oak (Quercus crispula Blume) sapling and its physiology, especially the radial transport of water containing inorganic ingredients in the stem using the scanning electron microscope-energy dispersive X-ray microanalyzer (SEM-EDXA) method. The resting potential of a sapling could be monitored continuously with our measuring apparatus. Changes in resting potential were due to the light. The hyperpolarization and depolarization peaks of the resting potential, whose absolute voltage was about 10mV, occurred right after lights-off and lights-on, respectively. The resting potential was found to show periodic responses for each day unit. At night (lights-off), the resting potential tended to depolarize with an increase in tangential strain. On the other hand, during the daytime (lights-on) the resting potential tended to hyperpolarize, depolarize, or show a nearly constant value for the tangential strain. The water containing inorganic ingredients was transported, via transpiration, in both directions between the mature xylem zone and the phloem zone through differentiating xylem cells. This water transport within a tree stem had a significant effect on the diurnal changes in resting potential.Part of this paper was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, April 3–5, 1997     

Effects of restricted feeding on growth of red sea bream and sedimentation of aquaculture wastes

For improving the economic and environmental sustainability of fish farming, it is necessary to optimize feeding regimes. From this viewpoint, we monitored the growth and mortality of red sea bream (Pagrus major), C and N fluxes and sediment chemistry at 2 commercial fish cages; cage 1 (conventional satiation feeding) and cage 2 (restricted feeding: same feeding frequency but 18% reduction in the feed amount) for 276 days. The similar specific growth rates (0.43% in cage 1 and 0.39% in cage 2) but different feed conversion efficiencies (0.54 in cage 1 and 0.62 in cage 2) and mortality (> 2-times higher in cage 1) between the 2 cages, indicate overfeeding in cage 1 culture. Elemental and stable isotopic analyses of sediment trap materials enabled the quantification of waste feed- and fecal matter-derived organic matter (OM) separately. The results shows that (1) aquaculture-derived OM comprised most of the fish-farm settling OM, excluding the period from January to April, when natural OM often accounted for a half of the bulk OM, (2) there was a difference in the seasonal trend between the fluxes of waste feed and fecal matter, and (3) there were no differences in the percentage compositions and fluxes of waste feed and fecal matter between the 2 cages. The isotopic analysis showed that the waste feed-derived OM in the sediment below cage 2 was 24% less than that below cage 1, suggesting effect of restricted feeding. Determining the relative amount of waste feed and fecal matter in settling and sedimentary OM is an effective method to evaluate the optimum feeding regime.     

Phytotoxic activity of Chinese violet (Asystasia gangetica (L.) T. Anderson) and two phytotoxic substances

Chinese violet (Asystasia gangetica (L.) T. Anderson) is a perennial invasive weed belonging to Acanthaceae. Leaves of this weed have been suggested to possess phytotoxic activity. However, phytotoxic substances in this weed have not yet been reported. Therefore, the present study investigated phytotoxic activity of Chinese violet extracts and phytotoxic substances. The extracts of Chinese violet leaves inhibited the root and shoot growth of cress, lettuce, alfalfa, barnyard grass, ryegrass, and timothy, where the level of inhibition increased with increasing extract concentrations. Bioassay‐guided separations of the extracts led to isolation of two phytotoxic substances, indole‐3‐carboxaldehyde and (6R,9S)‐3‐oxo‐α‐ionol. Indole‐3‐carboxaldehyde significantly inhibited the root and shoot growth of cress at concentrations ≥100 and 30 μmol L^?1, respectively, and concentrations of the substance required for 50% growth inhibition were 210 and 127 μmol L^?1 for cress roots and shoots, respectively. The other substance, (6R,9S)‐3‐oxo‐α‐ionol, was reported to have strongly inhibited cress roots and shoots. The present results suggest that Chinese violet contains two phytotoxic substances indole‐3‐carboxaldehyde and (6R,9S)‐3‐oxo‐α‐ionol, and those substances may play an important role in the phytotoxic activity of Chinese violet.     

Acute myelomonocytic leukemia negative for alpha-naphthyl acetate esterase stain in a Holstein cow

A 4-year, 7-month-old Holstein cow presented with anorexia. Physical examination revealed masses in the interscapular region and vagina. Blast cells were detected in the masses and peripheral blood by fine needle aspiration cytology and hematological examination. By bone marrow aspiration, blast cells constituted up to 24.2% of all nucleated cells, and 22% and 2% of non-erythroid cells stained positive for myeloperoxidase and alpha-naphthyl acetate esterase (ANAE), respectively. Pathological examination revealed the mass lesions consisted of a proliferation of tumor cells, which were positive for monocytic markers (HLA-DR and Iba-1). The cow was diagnosed with acute myelomonocytic leukemia (AMML). Even when tumor cells are ANAE-negative, AMML cannot be completely ruled out and should be considered when diagnosing cattle with leukemia/lymphoma.     

Integrating agroecology and landscape multifunctionality in Vermont: An evolving framework to evaluate the design of agroecosystems

Agroecosystems cover vast areas of land worldwide and are known to have a large impact on the environment, yet these highly modified landscapes are rarely considered as candidates for landscape design. While intentionally-designed agricultural landscapes could serve many different functions, few resources exist for evaluating the design of these complex landscapes, particularly at the scale of the whole-farm. The objective of this paper is to introduce an evolving framework for evaluating the design of agroecosystems based on a critical review of the literature on landscape multifunctionality and agroecology. We consider how agroecosystems might be designed to incorporate additional functions while adhering to agroecology principles for managing the landscape. The framework includes an assessment tool for evaluating farm design based on the extent of fine-scale land use features and their specific functions, to consider the present state of the farm, to plan for future conditions, or to compare alternative futures for the design of the farm. We apply this framework to two farms in Vermont that are recognized locally as successful, multifunctional landscapes. The Intervale Center, an agricultural landscape located within the city limits, serves as an incubator for new farm startups and provides unique cultural functions that benefit the local community. Butterworks Farm, a private operation producing organic yogurt and other food products, achieves important ecological functions through an integrated crop-livestock system. These farms and many others in Vermont serve as models of a framework that integrates landscape multifunctionality and agroecology in the design of the landscape. In the discussion section, we draw from the literature and our work to propose a set of important themes that might be considered for future research.     

Salinity intrusion and rice production in Red River Delta under changing climate conditions

This study was carried out to identify the vulnerability of rice production to salinity intrusion arising from climate change in Giao Thuy, a coastal district of Nam Dinh Province, located in Red River Delta in Vietnam. From the analysis of historical climate data at Nam Dinh city, both mean maximum and minimum temperatures increased by about 0.3 and 0.1 °C per decade, respectively, during the period of 1961–2010. Salt concentration of the river water was higher at the irrigation gate closer to river mouth (Con Nhat) than at the upstream gate (Ha Mieu), which generally increased from 2003 to 2012, with the average maximum concentration up to 2.13 % at Con Nhat gate in 2010. The salt water concentration in the riverside field outside the dyke reached 3.6 %, while among the fields within dyke the salinity was only 0.7 % at maximum in January 2013, and the values were higher in paddy fields close to the dyke than far from the dyke. Average yield among the selected 27 fields from 2011 summer to 2013 spring rice was higher in spring rice (748 g m^?2) but lower in summer rice (417 g m^?2) mainly due to unfavorable weather such as cold spell at flowering and flood at harvesting time. Rice yield was lowest in general in the most downstream commune Giao Thien, and was significantly lower in field located close to the dyke than those far from the dyke. This spatial variability of rice yield may not be directly attributable to salinity, but to the other factors such as shift of irrigation intake gate to further upstream and/or different management such as less input of N fertilizer and use of traditional local variety.     

Taurine is an essential nutrient for yellowtail Seriola quinqueradiata fed non-fish meal diets based on soy protein concentrate

The requirement of dietary taurine in yellowtail fed a non-fish meal (FM) diet based on soy protein concentrate (SPC) was examined by a feeding trial. A recovery test (RCT) was also conducted to confirm the requirement of dietary taurine in yellowtail fed the SPC diet. The non-FM diet including 58% SPC as the protein source was supplemented with 0% (NTS) and 4.5% taurine (TS). A diet including 58% FM was also included as a reference. Juvenile fish (initial BW; 470 g) were fed one type of experimental diet for 39 weeks. The RCT group was fed the taurine un-supplemented SPC (NTS) diet for the first 23 weeks, and then fed the taurine supplemented SPC (TS) diet for 16 weeks. Tissue taurine concentration of the NTS group was significantly lower (P < 0.05) than that of the FM group. Specific growth rate (SGR) and feed conversion ratio (FCR) of the NTS group was significantly inferior compared to the FM group. In the NTS group, green liver syndrome was observed in all the samples. In contrast, tissue taurine concentration of the TS group increased to a similar level to that of the FM group. Compared to the NTS group, SGR and FCR of the TS group were significantly improved (P < 0.05) by taurine supplementation to the SPC diet. Moreover, yellowtail of this group could be reared for a long term without any physiological abnormalities, and their physiological condition and performance were comparable to the fish fed the FM diet. Although the physiological condition and performance of the RCT group was markedly inferior as the NTS group at the 23rd week (wk23) of the feeding trial, the physiological condition and performance of the RCT group markedly improved by the switch of the NTS diet to the TS diet at the end of feeding trial on the 39th week (wk39). These results indicate that yellowtail fed a non-FM diet based on SPC require taurine as an essential nutrient for maintaining normal physiological condition and growth performance.