Inoculant rhizobia suppressed root-knot disease,and enhanced plant productivity and nutrient uptake of some field-grown food legumes

The potential effect of rhizobial inoculation on root knot nematodes in chickpea, mungbean and pigeonpea were studied under field condition. The seed treatment with respective rhizobium strains increased the nodulation, leghemoglobin content, bacteriod population, plant growth, yield and nitrogen uptake of three three food legumes compared to the plants without the rhizobium treatment. The nematode (1500?juveniles/kg soil) incited oval galls on the roots of the three legumes, and suppressed plant growth and yield. The galling, egg mass production and soil population of the nematode was greater on the plants without the rhizobium treatment. The pure culture and culture filtrate of the rhizobium strains suppressed the egg hatching and induced mortality to the juveniles of M. incognita over control. The nematode infection reduced the nodulation, bacteroid population and leghemoglobin contents of the nodules and NPK uptake by the plants. Hence, the rhizobia treatment shall be integrated to common agronomic practice of food legume cultivation so as to enhance crop productivity and to protect roots from nematode attack.     

Field response of legumes to inoculation with plant growth-promoting rhizobacteria

Carrier-based (soil/FYM, 1:1) plant growth-promoting rhizobacteria (PGPR) isolates (Bacillus subtilis, Klebsiella planticola and Proteus vulgaris) were tested individually and in combination with Bradyrhizobium japonicum and Rhizobium leguminosarum biovar viciae under field conditions on soybean and lentil crops, respectively, under field conditions. Inoculation of soybean (Glycine max) cv. Pusa 22 with B. subtilis produced maximum nodule number, mass and nitrogenase activity (acetylene reduction activity, ARA) followed by B. japonicum (SB 271). Maximum soybean yield was registered with the coinoculation of B. japonicum and B. subtilis over an uninoculated control. Maximum nodulation in the lentil (Lens culinaris) cv. L 4147 was obtained with a combination of R. leguminosarum (L-12-87) and P. vulgaris inoculation followed by a single inoculation with Rhizobium and B. subtilis. None of the PGPR isolates either singly or in coinoculation with R. leguminosarum could significantly influence the yield of the lentil crop.     

高酸值米糠油酯化脱酸成生物柴油原料

为充分利用高酸值米糠毛油,将其脱酸成生物柴油原料。采用酯化脱酸方法,通过对多种酯化脱酸催化剂的比较,结果表明氧化锌具有较强的催化活性。氧化锌作为米糠油酯化脱酸的催化剂,分别考察了甘油添加量、催化剂添加量、反应温度、反应时间对酯化脱酸的影响。得到了以下较优工艺参数：真空度为0.1 MPa,甘油添加量为理论甘油量1.044 g,催化剂添加量为油质量的0.1%,反应温度200℃,反应时间6 h。在此优化条件下,米糠油的酸值从38.14 mg/g降至5.17 mg/g,满足了作为生物柴油生产原料的要求。     

Use efficiency of nitrogen from biodigested plant material by ryegrass

Apparent nitrogen‐use efficiency of the applied mineral N (NUE_min) in effluent from biodigested plant material (BE; C : N_org ratio 14:1; mineral N–to–total N ratio 0.5:1) and a nitrate‐based inorganic fertilizer (IF), both applied at two rates was investigated in a six‐month pot experiment with Italian ryegrass (Lolium multiflorum Lam.). Dry‐matter (DM) production was 7% lower and total amount of N in aboveground biomass was 8% lower in BE than in IF at 40 d after sowing (DAS), equal at 81 DAS, and higher in BE than in IF at 136 and 172 DAS. NUE_min calculated on the basis of accumulated N in aboveground biomass of ryegrass in fertilized treatments compared to a control without N application was significantly lower in BE than in IF up to the third cut (136 DAS). Total NUE_min, total N recovery, and amount of foliage DM were similar for both fertilizers at the end of the experiment. Root biomass, total DM produced including roots and stubble, the fraction of root N to total plant N, and soil mineral N at 172 DAS were higher for BE than for IF. Mineral N applied with biogas‐reactor effluent was almost as effective as the nitrate‐based mineral fertilizer used for comparison. Within the six‐month experimental period net N mineralization, estimated at 12% of organic N in effluent, was not substantial. Hence, the organic compounds in the effluent were relatively recalcitrant.     

Determination of strophanthidin in ingesta and plant material by LC-MS/MS

An LC-MS/MS method was developed for the semiquantitative determination of strophanthidin glycosides in ingesta from animals. Strophanthidin glycosides were simultaneously extracted and hydrolyzed to the strophanthidin aglycone using aqueous methanolic hydrochloric acid and the extracts cleaned up using solid-phase extraction. Extracts were analyzed using reverse-phase HPLC coupled with positive ion electrospray mass spectrometry. Characteristic product ion spectra were produced by fragmentation of the [M + H](+) precursor ion for each analyte. Quantitation was performed using the internal standard method with digitoxigenin serving as the internal standard. The method detection limit was calculated to be 0.075 microg/g, and the limit of quantitation was calculated to be 0.24 microg/g for strophanthidin in control rumen samples. This method was used in diagnostic investigations to confirm fatal strophanthidin glycoside poisonings in horses.     

Challenges to the exploitation of host plant resistance for Striga management in cereals and legumes by farmers in sub-Saharan Africa: a review

Striga hermonthica, Striga asiatica and Striga gesneroides are obligate root parasites that cause severe yield losses in cereals and legumes in sub-Saharan Africa. Genetic control of Striga through resistance is widely considered to be the most practical and economically feasible method for long term control. The paper presents a comprehensive account of the Striga resistance mechanisms and environmental limitations to their usage in sub-Saharan Africa. Components of Striga resistance in cereals and legumes include low germination stimulant production, low haustorial initiation factor, mechanical barriers, incompatibility, antibiosis and Striga avoidance due to root growth habits. The successful exploitation of resistance has been limited by existence of specificity towards hosts, parasites that have evolved races specific host cultivars, Striga genetic variance which enables parasite to adapt to new resistance alleles and diverse hosts which support the parasite even in the absence of cereals together with low fertility due to nutrient mining in the smallholder sector. The results imply that different resistance mechanism may need to be present in genetically heterogeneous varieties or cereals with different resistance mechanisms may be rotated in the same field. Comprehensive Striga management systems should also address soil fertility in the small holder farmers of sub-Saharan Africa.     

Extraction of calcium fractions from plant material

Abstract

Calcium was extracted from leaves sequentially with water, 0.5M sodium nitrate, 2M acetic acid and 2M hydrochloric acid. Water and hydrochloric acid removed well defined fractions; water soluble calcium was mostly present in complexed form; hydrochloric acid removed only calcium oxalate. The results show that some oxalic acid may be produced by acid hydrolysis of plant constitutents during extraction with hydrochloric acid.

Drying of leaves prior to analysis altered the distribution of calcium; water soluble calcium decreased while acetic and hydrochloric acid soluble calcium increased.     

The determination of phosphorus in Kjeldahl digests of plant material by automatic analysis

Abstract

A method is proposed for the determination of phosphorus in plant material using a modified Kjeldahl digestion and a Technicon Autoanalyzer. The procedure depends upon the formation of phosphomolybdate and its reduction to molybdenum blue by ferrous ammonium sulphate. The method enables the simultaneous determination of phosphorus and nitrogen on the same plant digest.     

Whey liquid waste of the dairy industry as raw material for potable alcohol production by kefir granules

Kefir granular biomass was used in the fermentation of sweet whey and proved to be more effective compared to single-cell biomass of kefir yeast. The operational stability of the biocatalyst was assessed by carrying out 20 repeated batch fermentations. Levels of ethanol productivity reached 2.57 g L(-1) h(-1)), whereas the yield was 0.45 g/g. The fermentation time was only 8 h. Mixtures of sweet whey with molasses were fermented at initial densities ranging from 4.2 to 10.2 degrees Be and resulted in ethanol yield factors between 0.36 and 0.48 g of ethanol/g of utilized sugar. Lower degrees Be values led to an increase of percentages of ethyl acetate on total volatiles determined and a reduction of amyl alcohols. The addition of 1% black raisin extract to whey appears to promote whey fermentation, whereas the same was not observed in the case of white sultana extract addition. It was finally established that it is preferable to ferment mixtures of whey-molasses by adding molasses in whey after the completion of whey fermentation.     

Simultaneous determination of copper and iron in plant material by an automated method

Abstract

Existing colorimetric manual methods for copper and iron have been adapted for simultaneous analysis by an automated method. Fifty samples per hour can be assayed. Calculation of results as parts per million in dry matter has been eliminated by a standardized weighing technique of the plant material.     

Determination of flavonoids in plant material by HPLC with diode-array and electro-array detections

A high-performance liquid chromatographic (HPLC) method with in-line connected diode-array (DAD) and electro-array (EC) detection to identify and quantify 17 flavonoids in plant-derived foods is described. Catechins were extracted from the samples using ethyl acetate, and quantification of these compounds was performed with the EC detector. Other flavonoids were quantified with DAD after acid hydrolysis. The methods developed were effective for the determination of catechins and other flavonoids in plant-derived foods. Responses of the detection systems were linear within the range evaluated, 20-200 ng/injection (DAD) and 20-100 ng/injection (EC), with correlation coefficients exceeding 0.999. Coefficient of variation was under 10.5%, and recoveries of flavonoids ranged from 70 to 124%. Purity of the flavonoid peaks was confirmed by combining the spectral and voltammetric data.     

Total nitrogen in plant material determinated by means of dry combustion: A possible alternative to determination by Kjeldahl digestion

Abstract

The use of dry combustion‐based analyzer (CHN‐600, LECO Corporation, St. Joseph, MI) for nitrogen (N) determination in plant material is described. The method was evalueted in inter‐laboratory proficiency test (International Plant‐Analytical Exchange) and compared with results obtained by the Kjeldahl method. Differences between methods were small and results were in very close agreement. However when differences did occur, correction for nitrates did not fully explain differences between the two methods. A high content of nitrates can lead to serious differences between results obtained by the Dumas and Kjeldahl methods. Accuracy for the dry combustion method was tested with certified reference materials. Long‐term evaluation of repeatability of a determination varied from 1% to 2% with respect to material analyzed or content of nitrogen.     

用于地膜原料的大豆秸秆粉碎预处理工艺参数优化

为了满足植物纤维制取机对大豆秸秆原料长度的要求,采用改进的揉切式粉碎机对大豆秸秆进行预处理,选取揉切机的主轴转速、喂入量以及秸秆的含水率为试验因素,以大豆秸秆粉碎长度为响应函数,对大豆秸秆原料的预处理工艺参数进行了组合试验研究。结果表明:1)各因素对于秸秆粉碎长度影响的贡献率从高到低排序为主轴转速、含水率和喂入量;2)预处理工艺的最优参数组合为喂入量168 kg/h、大豆秸秆含水率处于36%~58%、揉切机主轴转速处于1 100~1 300 r/min。在此工艺参数条件下,大豆秸秆粉碎长度分布符合植物纤维制取机所要求的70~85 mm的理想范围。研究结果为完善植物纤维地膜制造工艺体系提供了参考。     

Cassava-legume intercrop: II. Effects of relative planting dates of legumes on the productivity of legumes

ABSTRACT

The degree of complementarity vis-à-vis competition amongst the component crops, which is influenced by their relative planting dates, may affect the productivity of intercrop systems. This study assessed the effect of the relative planting dates of legumes on yield and yield components of three legume species. Field experiments were conducted in two consecutive years at two sites with contrasting soil types. Grain yield and yield components were determined at harvest maturity. A 4-weeks delay in incorporating legumes caused total yield loss of cowpea at both sites, decreased chickpea yield by 82% at the clay soil site, and led to negligible yield of Bambara groundnut in loamy sand soil. In contrast, sowing legumes 2 weeks after cassava decreased grain yield of cowpea (both sites), chickpea (clay soil) and Bambara groundnut (loamy sand soil). Intercropping decreased grain yield of chickpea (year 1) and Bambara (year 2) at the clay and loamy sand soil sites, respectively, but had no effect on cowpea yield. Although planting the legumes same time with cassava gave the highest grain yield, we suggest more studies, including sowing the legumes prior to planting cassava, before making categorical recommendations.     

Determination of saponins in legumes by direct densitometry.

Research has shown that dietary saponins may have health benefits. A simple, rapid method for the determination of saponins in legumes, using densitometry, is described. Saponin preparations, after pretreatment to remove nonsaponin components, are spotted in rows on a thin-layer chromatography plate, along with soyasaponin standards. The plate, without solvent development, is directly treated with sulfuric acid and heated. Violet spots develop which have a density proportional to the amount of saponin present. The standard curve has a correlation coefficient of 0.99 and is linear over the range of 1.25 to 10 microg of soyasaponins applied. The method has a coefficient of variation of less than 3% and compares favorably with quantitative thin-layer chromatography. Using this method the saponin contents of defatted soy flour (0.58%), dried navy beans (0.32%), and dried kidney beans (0.29%) were determined, and these results were found to be consistent with previous reports in the literature.     

Measurement of phosphorus in the soil microbial biomass: Influence of plant material

The effect of plant material on measurement of P in the soil microbial biomass was evaluated using ³²P-labelled and unlabelled wheat plants. Fresh root and shoot material released significant amounts of P to 0.5 n NaHCO₃ (pH 8.5) following CHCl₃ fumigation. Treatment with CHCl₃ released 13–20% root P and 68–75% shoot P where a 16 h extraction period was used. With a 30 min extraction, release was 39% for roots and 18% for shoots. Calculations based on published values for rooting densities of field crops, show that significant errors in determination of soil biomass P are likely to occur where the CHCl₃ technique is used. Errors from inclusion of root material in the sample can be minimized by extending the extraction time from 30 min to 16 h.     

Movement by rhizobium and nodulation of legumes

Several Rhizobium spp were tested for chemotaxis using a soft agar assay. Bacteria migrated in chemotactic bands in response to substances present in the agar medium. R. japonicum S-110 formed chemotactic bands in response to l-arabinose, l-canavanine, and yeast extract but not to several other common compounds, including several amino acids and sugars. These results suggested that simple compounds present in legume root exudates may attract these bacteria and aid in their rhizosphere accumulation and, thus, in the nodulation process. A slow-migrating mutant of R. japonicum S-110 was isolated. Microscopic examination showed that mutant populations had a much lower proportion of motile cells than did wild-type populations. Greenhouse nodulation tests, in which mutant and wild-type cells were mixed and used as inoculum, indicated that the mutant had less nodulation potential.     

Chemical markers for the evaluation of raw material hygienic quality in egg products

The aim of this research was to study uracil and lactic and acetic acids as chemical markers for hygienic quality evaluation of raw material in liquid pasteurized egg products. Uracil, absent in sound whole eggs, was formed in raw and pasteurized egg products as a consequence of high microbial contamination (>10(6) cfu/g) after a sufficient lag time, remaining stable at 4 degrees C but disappearing after 7 days of storage at 25 degrees C. Both lactic and acetic acids, starting from initial values of 1-7 mg/kg dry matter, presented trends similar to that of uracil; however, acetic acid never decreased during the storage of raw egg products. With few exceptions, all three metabolites were produced by Enterobacter cloacae, Escherichia coli, Morganella morganii, Serratia liquefaciens, Aeromonas hydrophyla, Pseudomonas fluorescens, Enterococcus avium, and Enterococcus faecalis, separately inoculated in whole egg samples. Uracil seems to be the most sensible marker, with a suggested limit corresponding to the detectable level.