高压静电场处理对红元帅苹果采后品质的影响

该研究利用自制的高压静电场保鲜实验台产生的-50 kV/m和-100 kV/m高压静电场处理红元帅苹果，贮藏过程中每4d测定1次果实呼吸强度、内源乙烯释放量、果实硬度和可溶性固形物含量变化，并在贮藏结束时，对果实品质进行感官评定。实验结果表明：高压静电场处理使红元帅苹果的乙烯释放高峰推迟4 d，乙烯释放高峰值显著低于对照，并且使果实呼吸跃变推迟8 d。高压静电场处理苹果，在20℃条件下贮藏24 d，果实硬度和可溶性固形物含量显著高于对照，果实新鲜程度、脆性、硬度、粉性、甜味和苹果味等感官指标显著比对照好（p<0.01)，表明高压静电场处理对保持红元帅苹果的采后品质具有显著作用。     

电场对作物种子影响有效性的综合评价方法

针对电场对作物生物效应的影响,利用数据包络分析的有关理论,给出了用于综合评价电场强度对作物生物效应影响的非参数方法和相应的数学模型,提出了用于生物效应-电场强度影响有效性分析的图形法和表格法,为探讨不同外部条件对作物综合生物效应的影响程度以及在不同电场强度下某一生理指标与综合生物效应之间的关系提供一种有效的分析工具.并应用该方法对不同电场强度对小麦种子幼苗形态指标株高、根长、鲜质量、干质量及生理生化指标POD、SOD、MDA的影响进行综合评价.结果表明:不同电场处理条件对小麦幼苗生长及生理生化过程产生不同影响,在0.5～6.0 kV/cm场强范围,随电场强度增加,生理指标呈振荡性变化,且2.5 kV/cm和4.0 kV/cm场强为最佳处理条件.     

静电场处理对贮藏番茄品质及生理变化的影响

为探讨静电场对番茄贮藏品质的影响,以“朝研219”绿熟番茄为试材,从控制软化和转红出发,筛选了适宜的静电场处理条件为：场强-200 kV/m,频度2 h/d。研究静电场处理对贮藏番茄品质和生理变化的影响,结果表明：静电场处理能显著延缓番茄果实硬度的下降,抑制由绿转红的过程;可以延缓果实可溶性糖含量的下降和可滴定酸含量的上升;经负高压静电场处理的番茄,呼吸跃变推迟6 d出现,乙烯峰的出现也延迟了3 d,相对电导率与丙二醛含量较对照明显降低,说明静电场处理可调控果实细胞膜透性的变化。     

梯度磁场对芝麻种子生物效应的影响

应用电子顺磁共振(ESR)波谱仪对磁场处理过的芝麻种子连续14d跟踪测量,结果表明磁场可促进芝麻种子内部自由基浓度增加,且其自由基浓度随贮藏时间的延长明显降低,14d后其自由基浓度降低30%以上。用最佳磁场强度分别对芝麻种子进行12min、24min、36min、48min和60min不同梯度处理,结果表明电流50A(磁场强度835G)的磁场处理芝麻种子36~48min生物效应最佳,能有效提高芝麻种子发芽率和发芽势,促进根系生长。     

农业生物的电磁环境效应研究综述

大量的实验证明静电场、静磁场和交变电磁场作用于农业生物体会产生各种各样的生物学效应,其中促进生物生长发育的效应称为正效应或兴奋效应,阻碍或破坏生物生长发育的效应称为负效应或抑制效应。该文总结了近年来国内外有关农业生物电磁环境效应研究的主要内容,及其在农业工程领域中的应用情况;指出了农业生物电磁环境效应的主要特点,并提出了对该领域进一步研究的几点建议。     

电场对油葵种子萌发影响的有效时间

电场环境对种子的影响属于当代效应,电场处理种子的生物效应是否存在有效时间,是值得关注的问题.在1.0 ～5.5kV· cm-1场强范围,油葵种子用不同电场条件处理,筛选产生显著性影响的处理条件.再用显著性影响条件处理油葵种子,试验研究电场对种子萌发影响的有效时间.结果表明,电场处理油葵种子显著提高种子的发芽势、发芽率及种子的超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性.电场对油葵种子萌发期的影响存在有效时间,有效时间为3周.在电场处理种子技术的应用中,电生物效应的有效时间是应该注意的问题.     

静电场对植物生长的生物效应研究

为了研究静电场对植物生长的影响以及更好地利用静电生物效应,设计了新型植物静电促长装置进行试验。结果显示,适宜静电场处理的小青菜和番茄,从出苗到成熟、收获的整个生育期,生物效应是显著的,经１０ｋＶ的正静电场处理,番茄出苗数增加了３０％,产量增加了９１．９％;小青菜出苗数增加３３．４％,产量增加１８．３％。并从能量观点探讨了静电生物效应的机理。     

高压脉冲电场对大豆分离蛋白功能性质的影响

该文研究了高压脉冲电场对大豆分离蛋白功能性质的影响。结果表明：随着脉冲强度和脉冲处理时间的延长，大豆分离蛋白的溶解度、乳化性、起泡性及疏水性都增加。当脉冲强度或处理时间大于35 kV/cm或432 μs(溶解度)、30 kV/cm或144 μs(乳化性)、35 kV/cm或432 μs(起泡性)及30 kV/cm或288 μs(疏水性)时，由于蛋白质分子变性程度增加，分子发生聚集，功能性质反而下降。     

我国高空气球诱变育种的研究进展

1 98 7～ 1 997年 ,利用高空气球搭载农作物种子和食用菌菌种 ,进行空间诱变处理 ,研究空间诱变效应。结果表明 :经高空气球搭载处理的农作物种子和食用菌菌种选育出的突变品系的生育期、抗病性和脂肪含量、铁元素含量、维生素C和产量性状比原亲本有明显的改良。说明此性状变异是可以遗传的。     

野生大麦氮素吸收利用的基因型差异

采用土培盆栽,研究16份野生大麦在同一低氮处理下全生育期氮素吸收利用的基因型差异,旨在筛选出具有高效利用氮素能力的基因型,为氮素高效利用大麦育种提供种质材料。结果表明：（1）生物量、氮含量和氮素利用效率的基因型差异最大都在抽穗期（CV=33.55%,18.93%,21.88%）,氮含量和氮素利用效率基因型差异拔节期最小...     

极低频脉冲电场与高压静电场对作物种子萌发影响的差异

为了明确基于极低频脉冲电场(pulsed electric field,PEF)的种子处理技术与基于高压静电场(highvoltage electrostatic field,HVEF)的种子处理技术的有效性及其差异,研究了极低频PEF和HVEF对绿豆生长的影响。结果表明,极低频PEF处理对绿豆幼苗的质量、芽长和根长都有明显的促进作用,相同强度的HVEF处理对绿豆幼苗的根长生长有一定促进作用,对芽长的影响不显著。机理研究显示,极低频PEF和HVEF处理均对萌发绿豆的氧化代谢和蛋白质代谢有一定影响,在种子萌发初期,极低频PEF处理促进了种子储藏蛋白的分解,在后期促进了新蛋白的合成,HVEF处理则对萌发后期的蛋白合成有一定促进作用。研究还发现,极低频PEF和HVEF均可通过诱发超氧阴离子自由基激活种子超氧化物歧化酶(SOD)活性,促进过氧化物酶(POD)的合成,但是,极低频PEF对SOD和POD的影响大于HVEF。讨论了极低频PEF和HVEF对绿豆萌发影响差异的原因。     

Influence of agricultural traffic and crop management on collembola and microbial biomass in arable soil

Collembola and microbial biomass C were investigated in a field experiment with controlled agricultural traffic and crop rotation over a period of 27 months. The wheel-induced compactive efforts were applied according to management practices within the crop rotation of sugar beet, winter wheat, and winter barley. Increasing wheel traffic produced increasing soil compaction, mainly due to a reduction in surface soil porosity. Increasing soil compaction was accompanied by a decrease in microbial biomass C and the density of collembola. The influence of soil compaction on microbial biomass C was smaller than that of the standing crop. However, for collembola, especially euedaphic species, a reduction in pore space appeared to be of more importance than the effects of a standing crop. Within the crop rotation, microbial biomass C and the density of collembola increased in the order sugar beet, winter wheat, and winter barley.     

Effects of seedbed properties on crop emergence: 1. Temporal effects of temperature and sowing depth in seedbeds with favourable properties

Abstract

Rapid and uniform crop establishment is a prerequisite for efficient crop production and minimal environmental impact. Experiments were carried out in shallow plastic boxes placed directly on the ground in the field for studies of the effects of seedbed properties on emergence of various crops. This paper presents an analysis of the time required for germination and emergence under near-optimal seedbed conditions. The crops studied were barley, oats, wheat, pea, rape seed, white mustard, sugar beet, red clover and timothy. The time required for germination generally increased with size of the seeds, presumably because larger seeds needed more water to initiate germination. This applied both when comparing different crops and different seed sizes of the same crop. However, considerable differences occurred between seed lots of the same crop and there were greater differences between seed lots of the same crop than between the three small grain crops studied. Growth rate of the seedlings generally increased with seed size, presumably because of increased energy content in the seed. Consequently, the most rapid emergence was obtained from small seeds at shallow sowing and from large seeds at deep sowing. The crops studied had a minimum temperature for germination and seedling growth close to 0 °C. Under optimal seedbed conditions, thermal time required for 50% germination of barley was typically about 65 °C days over this base temperature and for seedling growth about 6 °C days cm^?1. From 4 cm sowing depth, about 80 °C days were required for emergence but with considerable variations between seed lots. For rape seed or white mustard about 40 °C days were required for germination and about 8 °C days cm^?1 for the seedling growth.     

EPR studies on gamma-irradiated barley seeds: identification of trapped electrons.

Electron paramagnetic resonance (EPR) studies were conducted on barley seeds exposed to normal (H(2)O) and deuterated (D(2)O) moisture, irradiated with 750 Gy at 77 K. Reported here, for the first time, are the trapped electrons formed on gamma-irradiation of seeds at 77 K. Electrons are stabilized/solvated with an increase in the moisture content (H(2)O/D(2)O) of seeds. The recombination of the trapped electron with radical cation gave intense thermoluminescence emission at 110 K. With the increase in temperature and the destruction of singlet, unmasking of an underlying heterogeneous population of free radicals was observed. These free radicals emanate mainly from the endosperm (approximately 95% by wt of the seed), whereas irradiated embryos show a broad multiplet of comparatively low amplitude. Radiolysis of carbohydrate, proteins (approximately 95% of endosperm), and lipids could possibly be responsible for the heterogeneous population of free radicals. Peroxyl radicals were also observed on annealing.     

Crop stand density enhances competitive ability of spring barley (Hordeum vulgare L.)

Abstract

The aim of the research was to establish weediness, competitive ability and productivity of the crop. The experimental object was agrophytocenoses of spring barley – Hordeum vulgare L. – crop of spring barley ‘Aura’ and unsown soil, and weeds growing in them. The crop was formed sowing 0, 120, 200 and 280 kg ha^?1 (0, 2.7, 4.5 and 6.2 million seeds per ha^?1 respectively) seeds of spring barley ‘Aura’. Spring barley crop was not harrowed and herbicides were not applied. In the field experiment estimates were made of changes of weeds and spring barley inter- and within- species competition optimizing crop density. During three years of field experiment in the crop of spring barley annual weeds prevailed at 88–99%, such as Chenopodium album, Stellaria media, Erysimum cheiranthoides. Perennial weeds formed 1–12% of the crop weeds, such as Sonchus arvensis, Cirsium arvense, Equisetum arvense. General number of weed species in spring barley crops varied from 13 to 21. Weed abundance proportionally declined in the crops of higher density, hence, higher seed rate should be recommended for organic agriculture where weeds are controlled in non-chemical ways. Consistently increasing barley stand density, the competition between species (spring barley with weeds) gradually turned into competition within species (between barley plants) when a higher number of weaker and non-productive stems started forming. Spring barley yield did not significantly depend on the stand density. Increasing stand density enhanced cultivated crop yield to a certain level (200 kg ha^?1), since an increase in spring barley plant number resulted in the reduction in weight per plant and 1000 grain weight, which was compensated by an increase in the number of spring barley plants. Different spring barley density had an essential influence on the chemical composition of weeds which was similar to that of spring barley. Weeds accumulated the greatest amount of crude proteins, crude fat and crude fibre growing without spring barley.     

Staling Effects When Adding Low Amounts of Normal and Heat‐Treated Barley Flour to a Wheat Bread

The properties of a white wheat bread could be changed by adding normal or heat‐treated barley flour in small amounts (2 and 4%) to a white wheat bread recipe. Differences regarding gelatinization as well as retrogradation properties were found when analyzing the two flours in model systems. The heat‐treated flour was fully gelatinized due to prior time, temperature, and pressure treatment and could therefore absorb larger amounts of water than the other flours. In gelatinized model systems with 40% flour (dwb), the heat‐treated barley flour contained less retrograded amylopectin as compared with normal barley flour after storage for up to 14 days, whereas no differences were found with 20% flour (dwb). However, stored breads showed an increased retrogradation of amylopectin (as measured by differential scanning calorimetry [DSC]) when 2% pretreated barley flour was added as compared with addition of 2% normal barley flour. On the other hand, there were no significant differences at the 4% level. Addition of either of the barley flours resulted in less firm breads during storage as compared with the control breads. Increased water absorption in barley flour and thus increased water content in the breads or different water‐binding capacities of the flour blends could explain these results. The present study indicated that water had a stronger influence on bread firmness than the retrogradation of amylopectin. This conclusion was based on breads with pretreated barley flour being less firm than breads with normal barley flour, although the retrogradation, as determined by DSC, was higher.     

滚筒式静电选种机的增产效应研究

主要介绍了滚筒式静电选种机对水稻种子进行的清选和分级，并进行了室内试验和田间生产试验。数据显示，该机与普通选种机相比，能按生命活力进行分选，故能选出生命活力最强的种子。由于静电清选的过程也是高压静电场的处理过程，因此能提高种子的发芽率和发芽势，并提高作物产量，其显著性检验效果良好。     

极低频高压脉冲电场提高陈年棉种活力的参数优化

为研究极低频脉冲电场对陈年棉种活力的影响,该文利用高压脉冲电源和弧形电极-平板组成的电场系统在极间距离为50 mm条件下,以16 k V、10 Hz为中心点,利用Design-expert软件设计正交试验,高压脉冲电场处理棉种时间为40 s。并利用响应面分析法,对发芽势、发芽率、发芽指数、活力指数等4个指标进行参数优化,得出最优处理电压为16.25 k V,最优频率为10.90 Hz。在此基础上,对优化条件进行了试验验证。结果表明:陈年棉种在脉冲电压16.25 k V、脉冲频率10.90 Hz处理条件下,与对照相比,发芽势提高了44.2%,发芽率提高了56.8%,发芽指数提高了64.3%,活力指数提高了81.8%,各指标都达到极显著差异(P0.01)。陈年棉种的电场生物学效应对电场电压和频率都具有选择性,在电压为16.25 k V、频率为10.90 Hz的脉冲电场作用下,陈年棉种的电场生物学效应最明显,研究结果为后续作物种子高压电场处理的参数优化提供参考。     

Antioxidants,free radicals,storage proteins,and proteolytic activities in wheat (Triticum durum) seeds during accelerated aging

Accelerated aging was performed by incubation of wheat seeds at 40 degrees C and 100% relative humidity for 3, 4, 6, 10, and 14 days. The effects of the treatment on seed germinability and on several biochemical characteristics of flour (carotenoids, free radical and protein contents, and proteolytic activity) and gluten (free radical content and flexibility) were evaluated. A decrease of germinability was found during aging, the germination being completely inhibited after 14 days. The lutein content decreased gradually, without going to zero, while that of free radicals increased. A reduction of soluble proteins and a degradation of glutenins and gliadins were observed, associated with a substantial increase of protease activity and a decrease in gluten flexibility. The results were discussed in reference to those previously obtained by natural aging of wheat seeds of the same species and cultivar.     

Quality of Flours from Waxy and Nonwaxy Barley for Production of Baked Products

One nonwaxy (covered) and two waxy (hull-less) barleys, whole grain and commercially abraded, were milled to break flour, reduction flour, and the bran fraction with a roller mill under optimized conditions. The flour yield range was 55.3–61.8% in whole grain and increased by 9–11% by abrasion before milling. Break flours contained the highest starch content (≤85.8%) independent of type of barley and abrasion level. Reduction flours contained less starch, but more protein, ash, free lipids, and total β-glucans than break flours. The bran fraction contained the highest content of ash, free lipids, protein, and total β-glucans but the lowest content of starch. Break flours milled from whole grain contained 82–91% particles <106 μm, and reduction flours contained ≈80% particles <106 μm. Abrasion significantly increased the amount of particles <38 μm in break and reduction flours in both types of barley. Viscosity of hot paste prepared with barley flour or bran at 8% concentration was strongly affected by barley type and abrasion level. In cv. Waxbar, the viscosity in bran fractions increased from 428 to 1,770 BU, and in break flours viscosity increased from 408 to 725 BU due to abrasion. Sugar snap cookies made from nonwaxy barley had larger diameter than cookies prepared from waxy barley. Cookies made from break flours were larger than those made from reduction flours, independent of type of barley. Quick bread baked from nonwaxy barley had a loaf volume similar to that of wheat bread, whereas waxy barley bread had a smaller loaf volume. Replacement of 20% of wheat flour by both waxy and nonwaxy barley flour or bran did not significantly affect the loaf volume but did decrease the hardness of quick bread crumb.