Bioaccumulation of selenium by floating aquatic plants

The degree to which floating aquatic plants concentrate Se in tissues was determined for four species grown in solutions containing various levels of Se. Results of this greenhouse study showed that all four plant species, Azolla caroliniana, Eichhornia crassipes, Salvinia rotundi folia, and Lemna minor absorbed Se quickly upon exposure to Se in water as concentrated as 2.5 g Se mL^–1, and attained maximum tissue concentrations within 1 to 2 weeks. Azolla absorbed Se to the highest tissue concentration (about 1000 g Se g^–1 dry matter) from the 2.5 g Se mL^–1 solution, followed by Salvinia (700 g Se g^–1), Lemna (500 g Se g^–1),and Eichhornia (300 g Se g^–1). Plant growth appeared unaffected by solution Se concentrations lower than about 1.25 g mL^–1. These results indicate potential for rapid Se movement from water into aquatic food chains, and for use of aquatic plants for Se removal in wastewater treatment systems.     

Salt-tolerant forage cultivation on a saline-sodic field for biomass production and soil reclamation

Chemical reclamation of sodic and saline-sodic soils has become cost-intensive. Cultivation of plants tolerant of salinity and sodicity may mobilize the CaCO₃ present in saline-sodic soils instead of using a chemical approach. Four forage plant species, sesbania (Sesbania aculeata), kallar grass (Leptochloa fusca), millet rice (Echinochloa colona) and finger millet (Eleusine coracana), were planted in a calcareous saline-sodic field (EC_e = 9·6–11·0 dS m⁻¹, SAR = 59·4–72·4). Other treatments included gypsum (equivalent to 100 per cent of the gypsum requirement of the 15 cm soil layer) and a control (no gypsum or crop). The crops were grown for 5 months. The performance of the treatments in terms of soil amelioration was in the order: Sesbania aculeata ≅ gypsum > Leptochloa fusca > Echinochloa colona > Elusine coracana > control. Biomass production by the plant species was found to be directly proportional to their reclamation efficiency. Sesbania aculeata produced 32·3 Mg forage ha⁻¹, followed by Leptochloa fusca (24·6 Mg ha⁻¹), Echinochloa colona (22·6 Mg ha⁻¹) and Eleusine coracana (5·4 Mg ha⁻¹). Sesbania aculeata emerged as the most suitable biotic material for cultivation on salt-affected soils to produce good-quality forage, and to reduce soil salination and sodication processes.     

气吸滚筒式花生穴播器投种性能分析与试验

针对气吸滚筒式花生穴播器投种过程中种子不能准确落入导种机构而造成漏播、重播的问题,该研究提出了一种通过调整穴播器盖边缘开口位置和导种机构安装角度的方法寻求最佳投种轨迹,对种子脱离穴播器盖进入导种机构阶段建立动力学模型,明确了投种轨迹变化机理,确定了穴播器盖和导种机构的安装参数。借助EDEM仿真软件研究了穴播器盖和导种机构在不同安装角度下的投种性能,得出种子在与分种盘挡片接触状态下脱离穴播器盖边缘的投种性能最佳。选取穴播器盖安装角度、导种机构安装角度和机具前进速度为试验因素,以排种粒距合格率、漏播率、重播率为试验指标,在排种试验台上进行三因素三水平组合试验。结果表明：在穴播器盖安装角为17.10°、导种机构安装角为11.18°、机具前进速度为3.85 km/h的条件下投种性能最优,此时排种粒距合格率为95.37%。田间试验结果表明,调节穴播器盖安装角为17.10°、导种机构安装角11.18°,机具前进速度在3.05～4.65 km/h范围内,试验结果与台架试验结果基本相符,排种粒距合格率大于89%、漏播率小于7%,重播率小于5%,满足花生单粒精量播种要求。     

Oil quality and sugar content of peanuts (Arachis hypogaea) grown in Argentina: their relationship with climatic variables and seed yield

The ratio of oleic to linoleic acids (O/L) and the tocopherol content are important features in determining peanut (Arachis hypogaea) seed shelf life. Soluble carbohydrates are known to be important precursors in roasted peanut flavor. The chemical qualities of Argentine grain are different from those of other countries, but no previous studies that associate grain quality and environmental parameters have been performed. Relationships were determined between O/L, tocopherol and sugar contents, and variations in temperature and rainfall during the grain filling period of Florman INTA peanuts. Dry seed yield was used as another explanatory variable. Multiple regression procedure gave mean temperature (positive coefficient) and total precipitation (negative coefficient) as the explanatory variables for variations in O/L. Total precipitation and dry seed yield (both negative coefficients) were found to be predictor variables for tocopherol and sugar contents. Total precipitation was an explanatory variable included in all of the linear regression models obtained in this study.     

Analytical characterization of Moringa oleifera seed oil grown in temperate regions of Pakistan

The hexane-extracted oil content of Moringa oleifera seeds ranged from 38.00 to 42.00%. Protein, fiber, and ash contents were found to be 26.50-32.00, 5.80-9.29, and, 5.60-7.50%, respectively. Results of physical and chemical parameters of the extracted oil were as follows: iodine value, 68.00-71.80; refractive index (40 degrees C), 1.4590-1.4625; density (24 degrees C), 0.9036-0.9080 mg/mL; saponification value, 180.60-190.50; unsaponifiable matter, 0.70-1.10%; and color (1 in. cell), 0.95-1.10 R + 20.00-35.30 Y. Tocopherols (alpha, gamma, and delta) in the oil were up to 123.50-161.30, 84.07-104.00, and 41.00-56.00 mg/kg, respectively. The oil was found to contain high levels of oleic acid (up to 78.59%) followed by palmitic, stearic, behenic, and arachidic acid up to levels of 7.00, 7.50, 5.99, and 4.21%, respectively. The induction period (Rancimat, 20 L/h, 120 degrees C) of the crude oil was 9.99 h and reduced to 8.63 h after degumming. Specific extinctions at 232 and 270 nm were 1.70 and 0.31, respectively. Many parameters of M. oleifera oil indigenous to Pakistan were comparable to those of typical Moringa seed oils reported in the literature. The results of the present analytical study were also compared with those of different vegetable oils.     

Interaction of iron chelate and nitrogen fixation in peanuts grown on calcareous soil

The interaction of iron (Fe) nutrition and nitrogen (N₂) fixation was examined in peanuts grown in the field for two growing seasons. The treatments were: a) inoculated with Rhizobium, not fertilized with N, b) uninoculated, fertilized with N, and c) uninoculated not fertilized with N. These treatments were tested with or without Fe chelate application. Inoculated peanuts produced up to 42% higher N yield than the uninoculated, non‐fertilized plants. Moderately chlorotic peanuts fertilized with Fe did not increase significantly their yield but had bigger nodules than peanuts not fertilized with Fe. There were no interactions between Fe and N treatments, indicating that both nutrients were important for growth and for N₂ fixation. Remedy of Fe chlorosis on calcareous soils with FeEDDHA will not reduce N₂ fixation.     

The absorption and distribution of SR-85 by field grown Glycine max

Introduction

Contamination of crops and cropland by fission products as a result of fallout from nuclear explosions and waste from nuclear reactors is a matter of concern. It has been shown (4, 5) that the fission elements yttrium, cerium, zirconium, columbium, tellurium and strontium are absorbed from the soil and translocated in plants only to a limited extent. Of these elements, strontium is absorbed and translocated to the greatest extent. The other elements are apparently more strongly bound to the soil colloid.     

A simple field test for predicting ease of cultivation

A simple field test is postulated for assessing ease of cultivation. In the proposed test, representative clods are sampled from the field, and place in portable apparatus where they are split between a cone and a ball. The force and movement to split the clod are recorded; average peak force is then plotted against clod deformation at peak force. Some preliminary data have been accumulated and plotted over a range of soil conditions. With sufficient data, areas on the graph can be identified, indicating that the soil is in a suitable or unsuitable condition for cultivation by a given implement.     

优化高压电场处理提高高粱种子活力

为了探讨高压电场处理对高粱种子萌发活力的影响,以晋杂122#高粱种子为试材,采用种子发芽试验、生物化学分析及二次通用旋转组合设计相结合的方法,研究电场强度和处理时间对高粱种子的活力指数和内源赤霉素(gibberellin,GA)含量的影响,通过建模分析,寻求高压电场处理条件的优化方案。结果表明:不同高压电场(high voltage electric field,HVEF)处理对高粱种子活力指数和内源GA含量影响均达到显著水平(P0.05);二因素对高粱种子的活力指数和内源GA含量影响效应顺序为电场强度处理时间;电场强度和处理时间对高粱种子活力指数和内源GA含量影响有阈值效应;二因素耦合效应对高粱种子的活力指数的影响呈现负交互效应,对内源GA含量的影响表现出正交互效应,且交互效应显著(P0.05),二因素交互作用对内源GA含量影响大于对种子活力的影响;经模型寻优,同时满足活力指数≥14.25、内源GA质量分数≥11.55 ng/g的优化方案为:电场强度485.53~605.38 k V/m,处理时间31.41~48.99 min,在此基础上,进一步确定优化条件为:电场强度500 k V/m,处理时间36 min,经试验验证,高粱种子活力指数和内源GA质量分数理论值15.50、14.92 ng/g,与实测值(15.38±0.18)、(14.85±0.13)ng/g基本一致,进一步验证了方案的可靠性。研究结果为高压电场技术处理种子在农业生产中的应用提供理论依据。     

Uptake of sulfur by four cotton cultivars grown under field conditions

There has never been an intensive study of the sulfur (S) nutrition of cotton (Gossypium hirsutum L.) when grown under field conditions. Field studies were conducted on two non‐irrigated soils to evaluate the S‐uptake characteristics of four selected cotton cultivars that are representative of those produced in the Southern United States. Four cultivars with diverse genetic backgrounds, Deltapine 90, Coker 315, Paymaster 145, and Stoneville 825 were grown on a Norfolk fine sandy loam (fine loamy, siliceous, thermic, Typic Kandiudults) and a Decatur silt loam (clayey, kaolinitic, thermic, Rhodic Paleudults). Whole plants were collected at two‐week intervals over the growing season starting at 15 days after planting. The plants were partitioned into leaves, stems, burs, seed, and lint, and analyzed (except for lint) for S. Total S uptake when averaged over both soils and all four cultivars was 20.4 (±9.4) kg/ha [or 2.7 (±0.7) kg S per 100 kg lint produced]. Sulfur uptake on the Norfolk soil (15.6 (±8.5) kg/ha) was lower compared to the Decatur soil [25.1 (±7.9) kg/ha]. There were no cultivar differences in total S uptake on the Norfolk soil, but total S uptake on the Decatur soil was affected by the interaction between sampling date and cultivar. The concentration of S and S uptake by some plant parts were affected by the interaction between sampling date and cultivar, however, cultivar differences were not consistent among soils or over the growing season. Maximum daily accumulation of S occurred during the final two week sampling period at the end of the growing season (cumulative heat unit 1193–1444) during which an average of 29.5% of the total S was accumulated.     

Cultivars and cultivation systems for organic strawberry production in Norway

Cultivars and cultivating methods for organic strawberry production were studied in experiments in open fields and high plastic tunnels during four cropping seasons in southern Norway. In open fields, flowers and fruits were attacked by grey mould when the flowering and harvest seasons were wet, and marketable yield was reduced by up to 20%. Production in high tunnels showed a potential of high yields of fruits of good quality when strawberry powdery mildew was controlled. Berry size varied significantly among the cultivars. ‘Frida’ had the largest fruits followed by ‘Sonata’ and ‘Florence’, while ‘Polka’, ‘Korona’ and ‘Iris’ had the smallest fruits. All cultivars yielded well, but due to fruit decay caused by grey mould the marketable yield was significantly reduced, especially in open field. Grey mould was the most important factor influencing marketable yields. Fruits from matted rows were largest, while the highest yield was obtained on woven polyethylene. There were no effects of mulching methods on marketable yield or the amount of fruits with grey mould. High tunnels with good control of pests and diseases showed a potential of high and stable yields of good quality.     

杂交籼稻制种全程质量管理技术

生产合格的杂交水稻种子、规避质量风险是杂交水稻制种工作的重中之重.要确保种子质量,除了要统一思想认识、加强相关人员培训教育外,还需进一步制定严格的质量管理制度,明确各方职责,充分调动全员参与质量管理工作的积极性,认真抓好全程质量管理,即在种子生产的产前、产中、产后的每一个环节都要落实好质量控制技术措施,确保所产种子的各项指标达到国家标准.     

电晕场与介电分选提高水稻种子活力

为研究电晕场和介电分选对水稻种子活力的影响,该文利用弧形芒刺电极与下极板形成的电晕场对水稻种子在不同高压下进行处理,处理时间为4 min,结果显示,处理后水稻种子的活力有显著提高,并在17500 V （DC）时取得较优值;利用介电分选机在不同的分选电压下对水稻种子进行介电分选,选滚筒转速为25 r/min,结果发现,分选机对水稻种子有较好的分选效果,并且当分选电压为4000 V（DC）时,分选获得的 I 级水稻种子的活力最高。在上述最优条件下,先利用电晕场对水稻种子进行电晕场处理,再利用介电分选机对电晕场处理后的水稻种子进行介电分选,结果表明：水稻种子的各活力指标均高于只进行分选时的活力指标,其中Ⅱ级和Ⅲ级种子的活力指标有明显的提高,且Ⅱ级种子的活力指标较对照有显著提高（P＜0.01或0.05）,这也说明电晕场处理对低活力种子效果较好。同时,通过记录水稻种子每天的发芽数发现,电晕场处理和介电分选都能使水稻种子约提前1天发芽。这对后期研制电晕场与介电分选组合处理机提供了数据支持。     

Nitrogen uptake and allocation by field‐grown ‘Arapaho’ Thornless blackberry

Spring surface applications of ¹⁵nitrogen (N)‐labeled urea were made in March 1995 and 1996 on one and two‐year‐old, field‐grown ‘Arapaho’ blackberry (Rubus subgenus Rubus) plants. Individual whole‐plant samples were collected at pre‐harvest (late May), post‐harvest (mid‐July), and early dormancy (late October). Plant parts separated for analysis were roots, primocanes, floricanes, primocane leaves, floricane leaves; and fruits. Soil samples were also taken from within the plant drip line at each sample date. Plant tissues were washed, dry weights measured, ground for acid digestion, total N determined, and ¹⁵N analyzed. Plants collected in October had more total dry matter, with roots, primocanes, and primocane leaves contributing most to this total. Total N content decreased in all vegetative tissues (leaves and canes) from May to October. Compared to other plant tissues, floricane leaves and primocanes recovered significantly more fertilizer N in May while roots and primocane leaves contained more in October of each year. Floricanes and fruits did not increase in fertilizer N levels during the sampling period. Overall, the lowest percent fertilizer N recovery for whole plants was 12.8% for May 1995 and the highest was 32.4% for October 1996. Recovery of fertilizer N in the topsoil ranged from a low of 12.9% in October 1995 to a high of 38.6% in May 1996. There were no statistical differences in percent recovery of fertilizer N from topsoil among sample dates. Recovery of fertilizer N from subsoil in the October sample was much lower than that in May, probably due most to plant uptake, but also possibly to a downward movement out of the sample area by leaching or from other loss mechanisms. Averaging all sample dates, recovery was 59.5% in 1995 and 75.8% in 1996 for the plant and soil combined, with the remainder probably lost via volatilization, leaching, and/or denitrification.     

用低场核磁共振检测水稻浸种过程中种子水分的相态及分布特征

为研究水稻浸种过程中种子的水分相态及其分布特征,利用低场核磁共振快速、无损、准确的检测技术,通过硬脉冲回波序列CPMG(carr-purcell-meiboom-gill sequence)测量水稻种子横向弛豫时间T2,根据横向弛豫时间T2的差异区分种子内部的水分相态及其变化规律。试验结果表明:通过T2反演谱横向弛豫时间T2长短的差异,发现水稻浸种过程中种子内部水分存在结合水、自由水2种水分状态,同时可区分出内层水、中层水、外层水3种水分分层;二者均能通过回归方程合理的估测水稻在浸种过程中种子的吸水率情况;通过T2反演谱信号幅值大小的差异,发现水稻浸种过程中的种子总水含量不断上升,但由于判定依据及划分方式的不同,二者在水分的流动方式上略显差异。低场核磁共振技术对水稻浸种过程中种子内部的水分变化进行了直观的揭示,提供了一种高效的种子水分检测方法。     

Purification and characterization of lipase in buckwheat seed

To obtain basic information about enzymatic deterioration of buckwheat flour, triacylglycerol lipase (LIP; EC 3.1.1.3) was purified from buckwheat seed. The LIP consisted of two isozymes, LIP I and LIP II, and they were purified with purification folds of 60 and 143 with final specific activities of 0.108 and 0.727 mumol of fatty acid released per minute per milligram of protein at 30 degrees C using triolein as a substrate. Molecular weights were estimated to be 150 (LIP I) and 28.4 kDa (LIP I) by gel filtration and 171 (LIP I) and 26.5 kDa (LIP II) by SDS-PAGE. Optimal pHs of LIP activities were 3.0 (LIP I) and 6.0 (Lip II) using triolein as a substrate. Both LIP I and II reacted in the acidic pH range. Optimal temperatures were 30 (LIP I) and 40 degrees C (LIP II), and both LIP I and II were stable below 30 degrees C when p-nitrophenyl-laurate was used as a substrate. However, they were inactivated above 60 degrees C. On the other hand, when triolein was used as a substrate, optimal temperatures were 30 degrees C for both LIP I and II, and they retained 40% of their activity after a 4 h incubation of enzymes at 70 degrees C. LIP I and II had higher activity against triolein than monoolein or tri/monopalmitin. Most of the LIP activity was distributed in the embryo.     

Determination of the phytoalexin resveratrol (3,5,4'-trihydroxystilbene) in peanuts and pistachios by high-performance liquid chromatographic diode array (HPLC-DAD) and gas chromatography-mass spectrometry (GC-MS)

The phytoalexin resveratrol (3,5,4'-trihydroxystilbene) in edible peanut (Arachis hypogaea L.) and pistachio (Pistacia vera L.) varieties grown in Turkey was analyzed by high-performance liquid chromatographic diode array and gas chromatography-mass spectrometric detection. trans-Resveratrol in six peanut varieties, five pistachio varieties, and four market samples ranged between 0.03 and 1.92 microg/g. The Cerezlik 5025 peanut (1.92 +/- 0.01 microg/g) and Ohadi pistachio genotype (1.67 +/- 0.01 microg/g) had significantly higher trans-resveratrol contents. Peanuts contained 0.03-1.92 microg/g (av = 0.84 microg/g) of trans-resveratrol, whereas pistachio contained 0.09-1.67 microg/g (av = 1.15 microg/g). With exposure to UV light for 1 min, trans-resveratrol concentrations of samples ranged from 0.02 to 1.47 microg/g and those of cis-resveratrol from 0.008 to 0.32 microg/g. The occurrence of resveratrol in peanut and pistachio was confirmed by total ion chromatograms (TIC) of bis[trimethylsilyl]trifluoroacetamide derivatives of resveratrol isomers and comparison of the mass spectral fragmentation data with those of a resveratrol standard. Formation of the cis-isomer in pistachios was higher than in peanuts.     

浙中红壤油菜田供钾特性和钾肥用量研究

通过多点田间试验研究红壤性水田油菜供肥特性和钾肥施用量 .1 8个田间试验施钾油菜籽增产幅度为 7.5～ 90 .8kg/亩 ,无钾区相对产量变幅为 48.2～ 93.1 % .1mol/LNH4OAc提取的土壤速效钾含量与无钾区相对产量之间达极显著相关 ,相关系数为 0 .6 44 9 (n =1 8) .土壤速效钾的“临界水平”为80mg/kgK ,能满足 95 %相对产量的“足够水平值”为 1 5 0mg/kgK ,系统研究平衡施肥法中各参数的确定 ,并用平衡施肥法和施肥曲线确定油菜钾肥合理用量 ,两种方法具有可比性     

水稻机摆钵育苗气吸滚筒式自动清堵排种器

针对水稻机摆钵育苗气吸滚筒式排种器精播催芽种子过程中吸孔堵塞严重,较难清堵这一问题,研制了气吸滚筒式自动清堵排种器,并进行了吸排种试验,试验结果表明,该排种器在球型窝眼半径为4.2 mm和气源流量为38、35 L/s的情况下,每穴1～2粒充种率较易达到97%以上。该排种器具有自动清堵功能,而且有利于充、排种子,适用于水稻机摆钵育苗。