Fate of malathion and chlorpyrifos methyl in rough rice and milling fractions before and after parboiling and cooking.

Long-grain rough rice treated with malathion (14 ppm) or chlorpyrifos methyl (Reldan) (6 ppm or 12 ppm) was sampled after 1,6, and 12 wk. Samples from each treatment were processed raw or were parboiled with fresh steeping water, once-used, and twice-used steeping water. Three replicates of rough rice and of each milling fraction were preserved, and three of milled rice were cooked. Chemical residues were measured on rough rice, hulls, brown rice, bran, milled rice, and cooked rice. Parboiling reduced residues on rough rice and hulls but tended to increase residues in the other fractions. Residues of Reldan in bran were substantially increased by parboiling. Doubling the amount of Reldan applied to rough rice approximately doubled the residues found in the milling fractions. Small amounts of the protectants survived all processing including cooking. Residues of malathion in cooked rice averaged about 0.016 ppm in nonparboiled and 0.013 ppm in parboiled rice. Residue of Reldan in cooked rice was commensurate with the amount applied to rough rice. When applied to rough rice at 6 ppm, residues of Reldan in cooked rice averaged 0.05 ppm in nonparboiled rice and 0l.065 ppm in parboiled rice. When applied to rough rice at 12 ppm, residues in cooked rice averaged .053 ppm in nonparboiled rice and 0.15 ppm in parboiled rice. Legal tolerances were not exceeded in any milling fraction. Reuse of the steeping water had little or no effect on residues.     

Water unextractable polysaccharides from three milling fractions of rye grain

Water unextractable material from bran, an intermediate milling fraction and sieved flour of rye grain were sequentially extracted at room temperature with saturated barium hydroxide, water, 4 M potassium hydroxide and water followed by extraction with 2 potassium hydroxide in a boiling water bath, giving repeatable recoveries of extracts and polysaccharide residue compositions in collected fractions. Total recoveries of polysaccharide residues in extracts and residue from the different water unextractable materials were 78–88%. Extracts in which 90–93% of the carbohydrates were arabinose and xylose residues were obtained by extraction with saturated barium hydroxide. Subsequent extraction with water yielded a fraction in which 64–68% of the carbohydrates were glucose residues. The extraction with hot alkali resulted in extracts in which 85–89% of the carbohydrates were arabinose and xylose residues. The ara/xyl ratio in the collected fractions ranged from 0.1–1.3, with the lowest ratios in fractions that precipitated after neutralisation of the 4 potassium hydroxide extract and the highest ratios in the unextractable residues. Structural characterisation with ¹H-NMR spectroscopy revealed varying substitution patterns for arabinoxylans in the different extracts and that glucose residues in the extracts essentially originated from mixed-linked β-glucan. The proportion of disubstituted xylose residues was lower in barium hydroxide extracts compared to the other main extracts. A highly branched heteroxylan was extracted with hot alkali. The polysaccharides found in the corresponding extracts for all the starting materials had generally similar structural features, but the yield differed considerably.     

播栽期对水稻产量和产量构成因素及生育期的影响

研究了不同播栽期对水稻产量和产量构成因素及生育期的影响。结果表明 ,随播栽期推迟 ,水稻产量有所降低。每穗成粒数减少是推迟播栽期引起水稻减产的主要原因 ,其次是千粒重的下降和成穗数的降低。针对目前的生产实际 ,提出了一些应对播栽期推迟的技术措施。     

Isozymes and classification of Asian rice varieties

Summary Enzyme variation detected by starch gel electrophoresis was used to investigate the genetic structure of Oryza sativa L. species. Fifteen polymorphic loci coding for 8 enzymes were surveyed among 1688 traditional rices from Asia. Multivariate analysis of the data resulted in identification of six varietal groups, with two major ones, groups I and VI, two minor ones, groups II and V, and two satellite ones, groups III and IV. Group I is found throughout tropical Asia; it encompasses most Aman rices in Bangladesh, the Tjereh rices in Indonesia and the Hsien rices in China. Group VI is found mostly in temperate regions and in high elevation areas in the tropics; it encompasses most upland rices from Southeast Asia, the Bulu rices from Indonesia and the Keng rices from China. Groups II, III, IV and V share common differences from groups I and VI which suggest an alternative evolutionary history. Groups II and V are found in the Indian subcontinent from Iran to Burma. Well-known components of these are Aus rices from Bangladesh for group II and Basmati rices from Pakistan and India for group V. Groups III and IV are restricted to some deepwater rices in Bangladesh and Northeast India. Based on analogy with other classifications, Group I might be considered as the Indica type and Group VI as the Japonica type. Such terms, however, have a depreciated meaning due to discrepancies among various classifications.Joint contribution: Institut de Recherches Agronomiques Tropicales et des Cultures Vivrières, 45 bis avenue de la Belle Gabrielle, F-94736 Nogent Sur Marne Cedex, France, and International Rice Research Institute P.O. Box 933, Manila, Philippines     

Distribution of ergot alkaloids and ricinoleic acid in different milling fractions

The sclerotia of the fungus Claviceps sp. are still a challenge for the milling industry. Ergot sclerotia are a constant contamination of the rye crop and have to be removed by modern milling technologies. Changing sizes and coloration of the sclerotia make it difficult to separate them from the grain. Ergot sclerotia are a problem when cleaning is insufficient and non-separated specimens or sclerotia fragments get into the milling stream and thus ergot alkaloids are distributed into the different cereal fractions. In model milling experiments, the residues of ergot in rye flour and the distribution of ergot into different milling fractions were investigated. Rye grains were mixed with whole ergot sclerotia and in another experiment with ergot powder and cleaned afterwards before milling. The ergot alkaloids ergometrine, ergosine, ergotamine, ergocornine, ergocryptine, ergocristineand their related isomeric forms (-inine-forms), and additionally ricinoleic acid as a characteristic component of ergot, were quantified in the different milling fractions. From the first experiment, it can be shown that after harvesting even simple contact of sclerotia with bulk grains during ordinary handling or movement of bulk grain in the granary is sufficient to contaminate all the healthy or sound rye grains with ergot alkaloids. Thereby, the amount of ergot residue correlates with the amount of peripheral layers of rye grains in the flour. In an additional experiment without sclerotia specimens, bulk rye grains were loaded with powder of sclerotia. After subsequent cleaning, aconcentration of ergot alkaloids was detected, which was tenfold higher than the ergot alkaloidconcentration of the experiment with intact ergot sclerotia.     

A DFT calculation on nonenzymatic degradation of isoaspartic residue

The mechanical properties of pristine and defective Si-based hybrid sheets are studied using molecular dynamics calculations for a temperature ranging from 100 to 800 K, in conjunction with a variable strain rate. When increasing temperature, the melting phase of the hybrids occurs from the solid to the liquid phase, while the increase in the strain rate enhances their elastic parameters. The absence of plastic stage reveals that the fracture pattern is brittle in these 2D materials. Under the uniaxial loading, the systems stretch, resulting in the failure of the crystalline skeletons that lose their rigidity with anisotropic behavior observed only for SiC. In defective hybrids, the point defects reduce the values of fracture strength and strain without affecting the brittle behavior of the sheets. The results impart that coupling high temperature to SiC material offers new possibilities for MEMS devices, whereas SiGe is a promising candidate for microelectronic devices.

     

Ferritin oxidation and proteasomal degradation: protection by antioxidants

The accumulation of oxidatively damaged proteins is a well-known hallmark of aging and several neurodegenerative diseases including Alzheimer's, Parkinson's and Huntigton's diseases. These highly oxidized protein aggregates are in general not degradable by the main intracellular proteolytic machinery, the proteasomal system. One possible strategy to reduce the accumulation of such oxidized protein aggregates is the prevention of the formation of oxidized protein derivatives or to reduce the protein oxidation to a degree that can be handled by the proteasome. To do so an antioxidative strategy might be successful. Therefore, we undertook the present study to test whether antioxidants are able to prevent the protein oxidation and to influence the proteasomal degradation of moderate oxidized proteins. As a model protein we choose ferritin. H₂O₂ induced a concentration dependent increase of protein oxidation accompanied by an increased proteolytic susceptibility. This increase of proteolytic susceptibility is limited to moderate hydrogen peroxide concentrations, whereas higher concentrations are accompanied by protein aggregate formation.

Protective effects of the vitamin E derivative Trolox, the pyridoindole derivative Stobadine and of the standardized extracts of flavonoids from bark of Pinus Pinaster Pycnogenol^® and from leaves of Ginkgo biloba (EGb 761) were studied on moderate damaged ferritin.     

不同磷浓度植株残体降解对紫色土磷素有效性的影响

植株残体降解可直接或间接地影响土壤磷素的有效性,为探讨不同磷浓度植株残体降解对紫色土磷分级体系的影响,结合31P核磁共振分析技术,选取了3种磷浓度不同的植物残体与两种紫色土进行室内模拟培养试验,得出了以下研究结论:(1)添加植株残体显著增强了紫色土呼吸强度,且紫色土分级体系中的活性磷含量均高于对照处理(2)31P-NMR分析结果得知,植株残体的正磷酸盐、磷酸单酯占浓缩液全磷比例的90%以上,高磷植株的正磷酸盐和磷酸单酯含量显著高于中磷和低磷植株,土壤磷素有效性的变化与植株残体的正磷酸盐和磷酸单酯含量有关;(3)紫色土分级体系中的活性磷在0 d含量最高,随着培养周期的延长,土壤磷素有效性会出现降低的趋势;酸性紫色土的累积呼吸强度、分级体系中活性磷(Resin-P、Na HCO3-Pt)所占比例均高于中性紫色土,与土壤钙含量有关。综上所述,植株残体的磷浓度越高,更有利于提高土壤磷素的有效性,本研究结果为农业生产中秸秆还田技术提供了理论参考。     

Phosphorus fractions in fallow systems of West Africa: Effect of residue management

The effects of burning, incorporation and surface mulching after one year of natural regrowth (NF) and Pueraria cover crop fallows on soil P fractions and maize and cassava yields were assessed. Data were collected between 1998 and 2000 as part of an on-going long-term fallow management trial established in 1989 at the International Institute of Tropical Agriculture (IITA), Ibadan, in the derived savanna zone of southwestern Nigeria. After NF in 1998, burning temporarily increased resin- (63%) and NaOH- (19%) extractable inorganic P fractions when compared with mulching and incorporation. Organic P and total extractable P decreased as the season progressed. Fallow systems and residue management options had no consistent and significant effect on P fractions. For both years after NF, and in 1998, after Pueraria fallow, residue management options had no significant effect on cassava yield. However, in 1999 (wetter year), compared with burning and surface mulching, incorporation of Pueraria fallow residues improved maize and cassava yields. Similarly, maize yield was improved in 1999 with incorporation of NF residues. Maize yield increases due to incorporation of NF residues were 23% compared with burning and 49% compared with mulching. Maize yield increases due to incorporation of Pueraria residues were 37% compared with burning and 47% compared with mulching. Cassava yield was increased by 31% compared with burning and by 26% compared with mulching. Longer period of time may be required to assess whether differences in soil P fractions and crop yields will occur between fallow systems.     

Sugar degradation during autoclaving: Effects of duration and solution volume on breakdown of glucose

As the autoclaving of a sugar together with other nutrient components enhances its degradation with the associated formation of toxic products, it is advisable to autoclave it separately from other medium components. In such cases, and to prepare growth media of consistent quality, it may also be necessary to adjust the duration of autoclaving according to the volume of the sugar solution. The results of an attempt to fine-adjust the autoclaving procedure are presented.
Glucose, used as model sugar in this investigation, was autoclaved for 20,32 or 44 min in volumes of 0.25. 1.2 and 5 1. The rise in temperature of the solutions was monitored by thermocouples. Glucose degradation was estimated by the rate of cyanide-initiated oxygen consumption. The rates were found to be inversely proportional to the volumes in a semilogarithmic plot. The T-t (temperature-time) value, the area under the solution temperature vs time curve, was found to be an independent variable from which the extent of glucose degradation could be deduced. For a chosen level of thermodegradation of glucose, the duration of autoclaving for solutions of different volumes could be determined graphically from a T-t value vs time plot.     

Effects of chloromequat chloride on related tall and dwarf rice varieties

The effects in growth room experiments of three levels of 2-chloroethyltrimethylammonium chloride (chloromequat chloride; CCC) at two nitrogen levels were studied on a tall rice variety and a mutant dwarf derivative. CCC was found to reduce plant height in both varieties, to increase tiller number and spikelet number on the main panicle or in total but to delay flowering. Chemical dwarfing cannot be regarded as an alternative to genetic dwarfing since mutants may be shorter than chemically treated tall genotypes and may themselves respond favourably to further treatment.     

Effect of drought on enzymes and free proline in rice varieties

Drought tolerant rice variety TKM-1 and susceptible variety Improved Sabarmati (I.S.) showed characteristic differences in peroxidase, RNase, nitrate r     

不同国家水稻品种的遗传多样性分析

探讨世界不同国家水稻品种的遗传多样性,旨在为各国品种资源的有效利用提供理论依据。本研究利用63对引物对36份来源于不同国家的水稻品种进行遗传多样性分析。共检测到269个等位基因,每个位点的等位基因数(Na)平均为4.54个,有效等位基因数(Ne)平均为3.22,基因多样性指数(H)平均为0.64,Shannon’s信息指数(I)平均为1.21,引物RM206、RM257、RM410、RM235、RM266的等位基因数较多在7条以上。所处纬度相近的国家或地区的水稻品种之间的遗传距离较近,被聚为同一类群,而所处纬度较远的国家或地区的水稻品种被分到了不同类群。结果表明,水稻品种之间的遗传差异与纬度和地理距离有很大的关系。     

Efficient plant regeneration from Indica (group 1) rice protoplasts of one advanced breeding line and three varieties

Regenerable embryogenic suspensions were established from one Indica (group 1) rice advanced breeding line and 9 Indica (group 1) rice varieties in 6–8 weeks. Four were chosen for protoplast culture and plant regeneration. About 4–7×10⁷ protoplasts were isolated from one gram of 8-week-old cell suspension. High plating efficiency (30.5%) and colony formation (13.7%) were obtained using nurse culture methods. A high plant regeneration frequency (67.5%) was observed for line IR57311-95-2-3. In total, 322 plants were regenerated. All the regenerated plants were fertile.Abbreviation 2,4-D 2,4-dichlorophenoxy acetic acid - NAA 1-naphtalene acetic acid     

糯稻品种的抗性评价与利用

我们从1977～1992年计14年,采用网笼育苗接虫鉴定与田间自然诱发,共鉴定国内外水稻品种（包括株系,杂交稻三系）32000多份,筛选出高抗至中抗稻飞虱的材料3247份,占11．44％,并从中评选出产量高,适应性广,糯性好,能抗褐飞虱、白背飞虱、稻瘟病、白叶枯病等多抗性的糯稻新品种,其中以“水源290”及“三五糯”表现最好。在湖南作双季晚稻亩产在420～550kg,作中稻在135～621kg。农民反映糯性好,抗性强,出米率,出酒率,做糍粑,年糕均优于其他糯稻品种。     

Comparative proteomic analysis of indica and japonica rice varieties

Indica and japonica are two main subspecies of Asian cultivated rice (Oryza sativa L.) that differ clearly in morphological and agronomic traits, in physiological and biochemical characteristics and in their genomic structure. However, the proteins and genes responsible for these differences remain poorly characterized. In this study, proteomic tools, including two-dimensional electrophoresis and mass spectrometry, were used to globally identify proteins that differed between two sequenced rice varieties (93–11 and Nipponbare). In all, 47 proteins that differed significantly between 93–11 and Nipponbare were identified using mass spectrometry and database searches. Interestingly, seven proteins were expressed only in Nipponbare and one protein was expressed specifically in 93–11; these differences were confirmed by quantitative real-time PCR and proteomic analysis of other indica and japonica rice varieties. This is the first report to successfully demonstrate differences in the protein composition of indica and japonica rice varieties and to identify candidate proteins and genes for future investigation of their roles in the differentiation of indica and japonica rice.     

Fine hyperspectral classification of rice varieties based on self-attention mechanism

The accurate identification of rice varieties using rapid and nondestructive hyperspectral technology is of practical significance for rice cultivation and agricultural production. This paper proposes a convolutional neural network classification model based on a self-attention mechanism (self-attention-1D-CNN) to improve accuracy in distinguishing between crop species in fields using canopy spectral information. After experimental materials were planted in the research area, portable equipment was used to collect the canopy hyperspectral data for rice during the booting stage. Five preprocessing methods and three extraction methods were used to process the data. A comparison of the classification accuracy of different classification models showed that the self-attention-1D-CNN proposed in this study achieved the best classification with an accuracy of 99.93%. The research demonstrated the feasibility of using hyperspectral technology for the fine classification of rice varieties, and the feasibility of using the CNN model as a potential classification method for near-ground crop monitoring and classification.