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.     

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。     

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.     

Agrobacterium tumefaciens-mediated transformation of japonica and indica rice varieties

Genetic transformation of rice (Oryza sativa L.) mediated by Agrobacterium ttumefaciens has been confirmed for japonica varieties and extended to include the more recalcitrant indica varieties. Immature embryos were inoculated with either A. tumefaciens At656 (pCNL56) or LBA4404 (pTOK233). Experimental conditions were developed initially for immature embryos treated with strain At656, based upon both transient and stable -glucuromdase (GUS) activities. However, plant regeneration following selection on G418 (pCNL56 contained the nptII gene) did not occur. Using the same basic protocol, but inoculating immature embryos of rice with LBA4404 (pTOK233), resulted in efficient (about 27%) production of transgenic plants of the japonica variety, Radon, and an acceptable efficiency (from 1–5%) for the indica varieties IR72 and TCS10. Transformation was based upon resistance to hygromycin (pTOK233 contains the hpt gene), the presence of GUS activity (from the gusA gene), Southern blots for detection of the integrated gusA gene, and transmission of GUS activity to progeny in a Mendelian 3:1 segregation ratio. Southern blots indicated two to three copies of the gene integrated in most transformants. Transgenic plants of both the japonica and indica varieties were self-fertile and comparable in this respect to seed-grown plants. Key factors facilitating the transformation of rice by Agrobacterium tumefaciens appeared to be the use of embryos as the expiant, the use of hygromycin as the selection agent (which does not interfere with rice regeneration), the presence of extra copies of certain vir genes on the binary vector of pTOK233, and maintaining high concentrations of acetosyringone for inducing the vir genes during co-cultivation of embryos with Agrobacterium.Abbreviations AS acetosyringone - DMRT Duncan's Multiple Range Test - GUS -glucuronidase - T-DNA transferred DNA We wish to thank Dr. Toshihiko Komari, Japan Tobacco Inc. for providing Ayrobacterium tumefaciens strain LBA4404 (pTOK322). Support by the Rockefeller Foundation in the form of a fellowship to R.R.A. and a grant to T.K.H. is acknowledged. This is journal paper number 14,914 from the Purdue University Agricultural Experiment Station.     

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     

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.     

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.     

强化栽培条件下稻田杂草发生特点和水稻品种竞争能力研究

水稻强化栽培条件下,稻田杂草以节节菜、陌上菜、异型莎草和千金子为主,其中与水稻有较强竞争力的为异型莎草和千金子。两优培九与杂草的竞争力较E52强。相同密度下,随行距扩大,水稻对杂草的抑制能力下降。当稀植时,与杂草竞争能力较差的E52对杂草抑制在不同行距问没有差异。就水稻强化栽培条件下杂草防治方法进行了讨论。     

Electrical penetration graphs from Nilaparvata lugens on resistant and susceptible rice varieties

The feeding behaviour of Nilaparvata lugens (Stal.) was electronically monitored on three rice varieties showing different levels of resistance in the Philippines, over an 8 h period, using a DC amplifier and a video-assisted observation method to simultaneously record honeydew production.Six electrical penetration graph (EPG) patterns are described by their frequency and amplitude characteristics. Patterns 4 and 5 were associated with the production of two different types of honeydew; basic honeydew containing amino acids was produced during Pattern 4 and acidic honeydew with no amino acids was produced during Pattern 5. These patterns are thought to indicate phloem and xylem ingestion by N. lugens respectively.Insects produced shorter periods of Pattern 4 on moderately resistant IR46 and resistant IR62 rice varieties than on susceptible IR22, although the time taken to produce the first period of Pattern 4 from the start of EPG recording did not differ between varieties. This suggests that N. lugens has the ability to initiate phloem ingestion on all three varieties, but that resistance mechanisms in IR46 and IR62 prevent sustained phloem ingestion, at least within the first 8 h of contact.

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Résumé Le comportement alimentaire de N. lugens Stahl a été enregistré életroniquement pendant 8 heures aux Philippines sur 3 variétés de riz présentant différents degrés de résistance, en utilisant un amplificateur DC associé à un système vidéo pour enregistrer simultanément la production de miellat.Six types d'enregistrements de pénétration (EPG) sont décrits avec leurs caractéristiques de fréquence et d'amplitude. Les types 4 et 5 sont associés à la production de 2 types différents de miellat; le miellat de base contenant des acides aminés est produit pendant le type 4, et le miellat acide sans acides aminés est produit pendant le type 5. On considére que ces types indiquent respectivement l'ingestion de phloème et xylème par N. lugens.Les périodes de type 4 ont été plus courtes sur les variétés modérément résistante IR46 et résistante IR62 que sur la variété sensible IR22, bien que le temps passé à produire la première période de type 4 depuis le début des enregistrements des EPG ne diffère pas suivant les variétés. Ceci laisse penser que N. lugens a la possibilité de commencer la consommation de phloème sur les trois variétés, mais que les mécanismes de résistance chez IR46 et IR62 empêchent une ingestion soutenue de phloème, au moins pendant les 8 premières heures de contact.

     

云南地方稻种持久抗瘟性的研究

1996～1999年,在不同纬度、不同海拔和不同稻作生态类型的重病区设立5个持久抗性稻瘟病鉴定圃.试验材料为云南的74份地方稻种资源,其中粳稻56份,籼稻18份(含野生稻3份).通过多个抗性组分进行了系统研究,初步表明大白谷(粳、墨江县)、毫弄早(籼、勐海县)、毫玉浪(籼、勐海县)、疣粒野生稻(野、西双版纳自治州)等具有持久抗瘟性能;其中疣粒野生稻高抗细菌性条斑病,对白叶枯病抗性为0级,接近免疫,中抗稻瘟病.通过对品种多抗性组分分析和品种抗性系统聚类分析,提出在不同生态类型时、空动态的病叶片上的产孢量和病斑表型可作为简易、快速鉴定持久抗瘟性指标.