Changes in Rice Ferulate and p ‐Coumarate Concentrations With Temperature and Nitrogen Fertilization

Detailed investigation of methylmercury accumulation in rice grain from Hg2+-spiked non-contaminated paddy field soils

A preparation method for Cd-containing brown rice grains as calibration standards was developed for X-ray fluorescence (XRF) analysis of Cd in rice grains. Calibration standards were prepared by adding 10 g of base rice grains (from Japan) to 100 ml of methanol containing 5−100 µg of Cd. The mixture was heated, cooled, and stored in a silica gel desiccator. Seven grams of each calibration standard was packed into a polyethylene cup (32-mm internal diameter and 23-mm height) covered with a 6-µm-thick polypropylene film and then subjected to XRF analysis. The calibration curves of Cd in brown and white rice grains showed good linearity in 0.50−10 mg kg−1. The detection limits of Cd in brown and white rice grains were 0.14 and 0.12 mg kg−1, respectively. The slopes of the calibration curves for Cd in brown and white rice grains were slightly different owing to absorption effects. The absorption effects were corrected using the ratio of the intensity of Cd Kα to that of Rh Kα-Compton scattering. After correction, the calibration curves of Cd in brown and white rice grains showed identical slopes. The spike test for 5 mg kg−1 of Cd in white rice grains (from Thailand), using the corrected calibration curves, showed quantitative recoveries (92−97%). Copyright © 2013 John Wiley & Sons, Ltd.

Complex cell walls of barley hulls contain phenolic constituents — hydroxycinnamic acids, mainly ferulic acid (3-methoxy-4-hydroxy-cinnamic acid, FA) and para-coumaric acid (4-hydroxycinnamic acid, PCA). Ferulic acid is produced via the phenylpropanoid biosynthetic pathway and is covalently cross-linked to polysaccharides by ester bonds and to components of lignin mainly by ether bonds. Various studies have consistently indicated that FA is among the factors most inhibitory to the biodegradability of plant cell wall polysaccharides. PCA is also covalently linked to polysaccharides (minor) and lignin (major), but PCA does not form the inhibitory cross-linkages as FA does. It is considered to represent plant cell wall lignification. The objective of this study was to determine the genotypic variation and magnitude of difference in the concentration of the hydroxycinnamic acids in terms of FA and PCA as well as their ratios in barley hull and seeds in sixteen varieties of barley collected during three years. These data will be correlated to barley nutrient availability in future study. The barley varieties included CDC Cowboy, Valier, TR251, Newdale, RCSL97, KXN/TLN-147 (AU), WABAR2160 (AU), Harrington, CDC Copeland, CDC Kendall, AC Metcalfe, CDC Dolly, McLeod, CDC Bold, CDC Helgason and CDC Trey. The focus of this study was on ferulic acid because of its inhibitory effect on rumen degradation and digestion which are highly related to nutrient availability in animals. The results showed significant differences (P < 0.01) a mong the barley varieties in ferulic acid and p-coumaric acid and their ratio. Whole barley seed contained higher (P<0.05) ferulic acid concentration than p-coumaric acid, ranging from 509 to 679 μg/g DM for ferulic acid and 131 to 345 μg/g DM for p-coumaric acid. The ratios of ferulic acid to p-coumaric acid ranged from 1.8 to 3.9. The ferulic acid concentration in hull was higher (P < 0.05) than that in whole seed, ranging from 2,320 to 4,206 μg/g DM. Percentage of ferulic acid content in hull and dehulled seed ranged from 38 to 70% and 30 to 62%, respectively. Growth year affect affected the hydroxycinnamic acid profiles in barley seed and hull. In conclusion, there were large differences in the ferulic acid and para-coumaric acid among the barley varieties indicating genotypic variation. Harrington contained highest and Valier contained lowest FA in whole seed. Barley TR251 contained lowest % of FA content in the hull and highest % of FA content in the dehulled seed. Future study is needed to understand the relationship between the hydroxycinnamic acid profile in barley seeds and hull and nutrient utilization and availability of barley in animals.

Inorganic versus organic fertilizers: How do they lead to methylmercury accumulation in rice grains

Combining biochar and zerovalent iron (BZVI) as a paddy field soil amendment for heavy cadmium (Cd) contamination decreases Cd but increases zinc and iron concentrations in rice grains: a field-scale evaluation

Since 2002, a joint research team from the International Water Management Institute and the Department of Agriculture, Thai Government, has reported that there are cadmium (Cd)-contaminated paddy fields in northern Thailand. We evaluated the current situation of the Cd-polluted paddy fields in this report. Home-consumed rice grains were collected from all 23 households in the village of Pha Te, Mae Sot District of Tak Province, Thailand. The Cd concentration in unhusked rice (Oryza sativa L.) grains ranged from 0.04 to 1.75 mg Cd kg−1, and the rice of more than half of the households contained Cd levels higher than the critical level of 0.4 mg Cd kg−1 polished rice, which is CODEX standard. Among the paddy fields, we selected one plot (1.2 ha) and analyzed Cd concentrations of the soil, and rice and soybean (Glycine max L.) grains. In this area, a rotation cropping system of wet-season rice and dry-season soybean is common practice. The soil Cd concentration ranged from 0.31 to 13.9 mg Cd kg−1 (total Cd) and 0.030 to 13.3 mg Cd kg−1 [extracted with 0.1 M hydrochloric acid (HCl)], the Cd concentration in the rice grains ranged from 0.12 to 1.27 mg Cd kg−1, and that in the soybean grains ranged from 0.07 to 0.80 mg Cd kg−1. The soil extractable Cd concentration was well reflected in the soybean grain Cd levels (r2 = 0.581), but not in the rice grain levels (r2 = 0.015), suggesting that rice grain Cd levels are influenced not only by the soil Cd concentration, but by other factors as well, such as soil water regime and soil pH. However, a significant difference in the grain-Cd concentration was found; that is, lower Cd in the cultivar “Khao’ Khaeng” and higher in the “Khao Dawk Mali 105”, which suggests a possibility of selecting a rice cultivar having low-grain Cd.

Ferulic acid fluorescence intensity profiles and concentration measured by HPLC in pigmented and non-pigmented cereals

A field experiment was established to support the hypothesis that application of different silicon (Si) fertilizers can simultaneously reduce cadmium (Cd) and arsenic (As) concentration in rice grain. The "semi-finished product of Si-potash fertilizer" treatment at the high application of 9000 kg/ha (NP+S-KSi9000) significantly reduced the As concentration in rice grain by up to 20.1%, compared with the control. Si fertilization reduces the Cd concentration in rice considerably more than the As concentration. All Si fertilizers apart from sodium metasilicate (Na2SiO3) exhibited a high ability to reduce Cd concentration in rice grain. The Si-calcium (CaSi) fertilizer is the most effective in the mitigation of Cd concentration in rice grain. The CaSi fertilizer applied at 9000 kg/ha (NPK+CaSi9000) and 900 kg/ha (NPK+CaSi900) reduced the Cd concentration in rice grain about 71.5 and 48.0%, respectively, while the Si-potash fertilizer at 900 kg/ha (NP+KSi900), the semi-finished product of Si-potash fertilizer at both 900 kg/ha (NP+S-KSi900) and 9000 kg/ha (NP+S-KSi9000), and the rice straw (NPK+RS) treatments reduced the Cd concentration in rice grain about 42, 26.5, 40.7, and 23.1%, respectively. The results of this investigation demonstrated the potential effects of Si fertilizers in reducing Cd and As concentrations in rice grain.

Reducing cadmium (Cd) concentrations in rice grains is important for food safety, particularly in acid paddy fields in South China where the soils have been previously contaminated with Cd. A field experiment was conducted to evaluate the effects of four alkaline amendments, i.e., lime, compost, biochar, and carbide slag on soil bioavailability and uptake of Cd in plants of two rice cultivars (Oryza sativa L.) in a Cd-contaminated acid paddy soil. The addition of these amendments significantly decreased the concentrations of CaCl2-extractable Cd by 13-41%. Cd in the acid-soluble fraction was decreased in these amended soils while it increased in the residual fraction. The amendments also decreased the uptake of Cd in the plants at the tillering and mature growth stages. The concentrations of Cd in plant tissues at maturity were in the order: root > shoot > bran > polished rice > husk. The amendment of carbide slag decreased Cd concentration in rice grains the most, followed by lime, biochar, and compost. The increases in soil pH and the decreases in the acid-soluble fraction of Cd (F1-Cd) indicated that these amendments can directly transform the highly availability fraction of Cd to a more stable fraction (residual Cd fraction) in soils. Furthermore, the Cd concentrations in polished rice grains of the two rice cultivars used were reduced by 66-67% by treatment with carbide slag. Our study suggests that carbide slag has a great potential to reduce the bioavailability and uptake of Cd in rice plants in Cd-contaminated acid paddy field soils.

Zinc concentration prediction in rice grain using back-propagation neural network based on soil properties and safe utilization of paddy soil: A large-scale field study in Guangxi, China

Cadmium (Cd) accumulation in rice has become a serious public concern; thus, it is important to find an effective approach to reducing Cd accumulation in rice grains to ensure food safety. To investigate the effects of different amendments on Cd accumulation in rice in Cd-contaminated farmland under different flooding treatments, a field experiment with three amendments (jade powder, biochar, and fly ash) and two flooding treatments (intermittent flooding and flooding throughout the whole growth period) was conducted. The results showed that:① without amendment application, the soil pH significantly increased, whereas the soil available Cd concentration decreased by 3.81%-17.27% and 2.25%-6.74% with the treatments of flooding throughout the whole growth period and intermittent flooding, respectively. Additionally, the immobilizing efficiency of the treatment of flooding throughout the whole growth period was better than that of intermittent flooding; ② under different flooding treatments, amendment application improved soil pH, resulting in a decrease in the soil available Cd concentration along with an increase in the residual Cd concentration. Under the treatment of intermittent flooding, the soil pH increased by 0.19-2.20 units, and the soil available Cd concentration and Cd concentration in rice grains decreased by 4.72%-22.68% and 2.60%-75.75%, respectively, with the application of different amendments. Under the treatment of flooding throughout the whole growth period, the application of different amendments decreased the soil available Cd concentration and Cd concentration in rice grains by 5.06%-36.63% and 13.28%-77.01%, respectively. The immobilizing efficiency in both flooding treatments was jade powder > biochar > fly ash. ③ Under different flooding treatments, the application of amendments significantly reduced the soil available Cd concentration and Cd concentration in rice grains. Among the three amendments, jade powder showed the best capacity of immobilizing efficiency with the treatment of flooding throughout the whole growth period; the soil Cd reduction rates were 36.63% and 25.16%, and the Cd concentrations in rice grains were 0.058 and 0.170 mg·kg-1 in 2019 and 2020, respectively. The Cd concentrations in rice grains were within the limitation of the National Food Hygienic Standard of China. Therefore, combining flooding throughout the whole growth period with jade powder can be considered as an ideal strategy for ensuring rice safety in Cd-contaminated farmland.

ABSTRACTWe examined the effect of two types of iron (Fe) material produced by the casting industry (spent steel shot [SSS] and residual iron material from steel shot production) on the mobility of arsenic (As) and cadmium (Cd) in soils. We also examined the uptake of these elements by rice plants (Oryza Sativa L.) under continuously flooded (CF) and water-saving (WS) cultivation. The application of both Fe materials (at 10 and 30 t ha‒1) strictly limited As mobilization in soils under CF cultivation. As a result, As uptake by rice plants declined, along with the total and inorganic As (iAs) concentration in rice grains. In comparison, As immobilization caused by the application of Fe material was less clear under WS cultivation. The rate of Fe material application was negatively correlated with As uptake by rice plants. It was also negatively correlated with total and iAs concentration in rice grains under both water management practices. The combination of applying Fe materials and WS cultivation decreased iAs concentration in rice grains to approximately one-fifth of that in rice grains produced from plants grown on soils without Fe material application under CF cultivation. CF cultivation strictly decreased dissolved Cd in soils, as well as Cd in rice grains with and without Fe material application. The application of Fe materials decreased Cd mobility and, hence, Cd uptake in rice plants, ultimately reducing the accumulation of Cd in rice grains under WS cultivation. Residual Fe material had a statistically greater effect at attenuating Cd accumulation in rice grains than SSS. The present study demonstrated the potential of combining by-product Fe material application and water management practices to attenuate iAs and/or Cd concentrations in rice grains. Practical countermeasures should be carefully adopted that consider the existing risks of iAs and Cd on each paddy field, and the combined effect of Fe material application and water management practices.

A study was conducted to evaluate the Protein status of White and Brown Rice grain in selected varieties at Anbil Dharmalingam Agricultural College &amp; Research Institute, Tiruchirappalli of Tamil Nadu, India during the period from June 2017 to May 2019. In the present study, sixteen different rice varieties cultivated in and around Tiruchirappalli district of Tamil Nadu as the test rice grains in terms of White and Brown rice in completely randomized design with three replications were tried. Screening and evaluation of protein content in 16 rice varieties were carried out to identify protein rich varieties. Biochemical analysis based on five different traits including contents of albumin(Alb), globulin(Glo), prolamin(Pro), glutelin(Glu) and total or gross grain storage protein (GGSP) were carried out. Results showed that the relative contribution of Albumin as 0.9 to 2.3 g/100 g, globulin as 0.67 to 2.3 g/100 g, prolamin as 0.28 to 2.73 g/100 g and glutelin as 2.0 to 6.18 g/100 g in Brown Rice; Albumin as 0.67 to 2.0 g/100 g, globulin as 0.652 to 2.0 g/100 g, prolamin as 0.20 to 2.3 g/100 g and glutelin as 1.684 to 5.258 g/100 g in White Rice. Results revealed a considerable variation also in gross grain protein contents among Brown and White rice of sixteen cultivars ranged from 5.087 to 9.644 g/100 g and 4.5 to 8.760 g/100 g respectively. Gross grain protein contents were higher in ASD-19, TKM (R) 12 and ADT 37 of Brown rice. Gross grain protein contents were higher in TKM (R) 12, ASD-19 and ADT-38 of White rice. The result on status of protein in Brown rice showed that ADT-40 had the highest Albumin content. ADT 37 exhibited the highest globulin content. The lowest prolamin content was found in TKM (R) 12, whereas the highest content of glutelin was found in ASD-19. The result of status of protein in White rice showed that TKM (R) 12 had the highest Albumin content. ADT 37 exhibited the highest globulin content. The lowest prolamin content was found in Anna (R) 4, whereas the highest content of glutelin was found in ASD-19. The highest Prolamin to Glutelin ratio was recorded in TKM (R) 12, CR 1009 /Ponmani and Anna (R) 4 for Brown rice. The overall results of this study revealed that ASD-19, TKM (R) 12 and CR 1009 /Ponmani were considered as Top three genotypes suitable for Tiruchirappalli district farmers based on consumer preferences.

ABSTRACTConcern over the food chain transfer of zinc (Zn) is increasing because of its importance in human health. A field experiment was conducted on a low Zn soil to determine the effect of different Zn fertilization strategies on grain Zn concentration and Zn allocation in different plant tissues of rice. Six treatments were used: (1) no Zn fertilization; (2) soil fertilization at transplanting; (3) Zn soil fertilization at transplanting and flowering; (4) foliar application during grain filling; (5) foliar applications during tillering, flowering, and grain filling; and (6) combination of treatments 3 and 5. Zn fertilization significantly increased Zn concentration in brown rice. The largest effect on grain Zn was observed by combination of soil and foliar applications. The increase in brown rice was much smaller (20%) than the increase in the vegetative parts (100%), indicating that grain Zn concentration of rice is not strongly increased by Zn fertilization. More increased Zn by Zn fertilization was allocated into straw not into grain. From the perspective of human nutrition, it seems that there is too little scope to enhance Zn concentration in rice by fertilization alone. the major bottleneck to increase Zn concentration in rice grain seems to be internal translocation/retranslocation of Zn from shoot to panicle or from rachis to grain, rather than root uptake of Zn from the soil.

Comparative study of efficiencies of purification of cadmium contaminated irrigation water by different purification systems