不同类型栽培大麦的辐射敏感性

用0—40krad~137Cs γ射线照射47个不同类型栽培大麦。结果表明,裸麦的辐射敏感性极显著大于皮麦。不同类型栽培大麦辐射敏感性的次序是:四棱裸大麦>六棱裸大麦>二棱裸大麦>四棱皮大麦>六棱皮大麦>二棱皮大麦。供试品种的敏感性可分为5个类型,即极迟钝型,迟钝型、中间型、敏感型和极敏感型。试验还表明,不同基因型大麦的细胞核体积与辐射敏感性无明显的相关关系,核体积的剂量效应曲线在30krad时出现一个峰值。     

苹果种质资源矮生基因型的研究

本文测定了38个杂交组合的2597个F_1代苹果实生苗新梢伸长区节间皮层或相应部位叶片中的过氧化物酶同工酶酶谱,统计了3种杂交类型(即普通型品种之间、普通型与矮生型品种之间、矮生型与矮生型品种之间)的过氧化物酶同工酶酶9带的比例。研究表明,该比例与杂交后代出现矮生型和普通型实生苗的理论比例相符,表明苹果新梢伸长区节间皮层和相应部位叶片申的过氧化物酶同工酶酶9带是矮生型苹果岭标记,而且可能是受两对互补基因所控制。     

温度对不同穗重型水稻叶片保护酶活性及同工酶表达的影响

通过人工控温,对不同穗重型品种叶片的过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化歧化酶(SOD)的酶活性及同工酶表达进行研究,结果表明:重穗型品种Ⅱ优162、冈优527在适温(24℃)、次高温(29℃)和高温(32℃)下,叶片中的3种保护酶活性都呈上升的趋势;而中穗型品种D优68和轻穗型品种E优540,在高温下其3种保护酶活性下降。从同工酶表达看,SOD的同工酶谱带在不同穗重型品种间无明显差异,且随温度的升高而减弱。CAT表达则在重穗型与中穗和轻穗型品种间有明显不同,特别是高温胁迫(38℃)下,中穗型和轻穗型品种谱带C1消失,而重穗型品种则产生1条新的CAT谱带C0。POD表达研究发现,不仅穗重型间,且在同一类型的品种间也存在差异性,但前者间的差异显著大于后者,表明不同穗重型可能存在不同的高温应答机制。     

辐射选育小麦易位系的研究

辐射处理六倍体小黑麦黑杂266×普通小麦克79F3-392的F0种子,通过一定的选育程序,选出了龙辐麦4号,龙辐10946和龙辐10877 3个易位系,经Giemsa-C带技术鉴定,其易位形式分别为6BS/6RL,2AS/2RL和7RL/7AL。酯酶同工酶和过氧化物同工酶的分析表明,3个易位系和黑杂266具有共同的特征酶带。试验证明,3个易位系具备双亲的优良特征特性,其中龙辐麦4号已由黑龙江省品种审定委员会审定推广种植。     

模拟微重力条件下马铃薯的同工酶检测及RAPD产物分析

为研究微重力条件下对植物生长发育的影响 ,本试验通过微重力仪连续改变方向来获得模拟微重力条件 ,对该模拟条件下马铃薯的组培苗进行了过氧化物酶同工酶谱及RAPD分子标记的实验。结果表明 ,微重力条件下马铃薯植株的过氧化物同Ⅰ酶谱出现了新的谱带且同工酶活性高于对照。RAPD方法利用 1 0碱基随机引物扩增基因组DNA ,结果说明其遗传物质没有发生变化。在微重力处理 1周后检测 ,发现处理与对照之间的过氧化物同I酶谱基本趋于一致 ,RAPD检测两者之间遗传物质一致     

玉米自交系及F_2分离群体花药培养中的过氧化物同工酶分析

利用聚丙烯酰胺凝胶电泳分析了两个花粉诱导率不同的自交系 (A3和A46)及其杂种F2 代分离群体在花药培养过程中过氧化物同工酶的变化。结果表明 ,花药培养 7d以后 ,高诱导率自交系A3及高诱导率F2 单株均出现Rf0 50和Rf 0 52 2条过氧化物同工酶谱带 ,而难诱导自交系A46和难诱导F2 单株无此特征。据此认为 ,过氧化物同工酶可以作为花培能力选择的一项较为可靠的生化指标。     

小麦抗根腐病突变体抗病机理的探讨

以离体筛选获得的小麦抗根腐病突变体及其亲本为材料,在根腐病菌毒素作用下,研究了过氧化物酶、超氧化物歧化酶和苯丙氨酸解氨酶等防御酶系的变化。结果表明,毒素可使上述酶活性、同工酶谱带发生改变。突变体酶的变化比亲本显著,这些变化与它们的抗病性强弱相一致。可以认为,突变体在毒素作用下具有较强的防御酶活性是产生较强抗性的原因。     

大豆品种间辐射敏感性差异机制的研究

用60_Coγ射线辐照13个大豆品种的种子表明,不同品种大豆的辐射敏感性存在明显差异。应用3~H-TdR掺入法研究受辐照种子浸种初期的DNA合成情况表明,受辐照的大豆种胚出现非S期DNA合成,即修复合成。品种间辐射敏感性差异与DNA修复合成有关,辐射敏感性高的品种DNA修复合成能力弱,辐射敏感性低的品种DNA修复合成能力强。     

春石斛兰类原球茎分化过程中抗氧化酶活性和可溶性蛋白的变化

以春石斛兰(Dendrobium nobileSw.)为试材,研究了类原球茎在分化芽和根系发生过程中抗氧化酶系统中多种酶活性及可溶性蛋白的变化规律。结果表明,在分化过程中抗坏血酸过氧化物酶(APX)、愈创木酚过氧化物酶(POD)、多酚氧化酶(PPO)和过氧化氢酶(CAT)的活性和可溶性蛋白含量均呈现先降后升的趋势;超氧化物歧化酶(SOD)活性则呈现先升后降的变化。对过氧化物酶同工酶和可溶性蛋白进行SDS-PAGE电泳发现,在分化过程中均有新谱带的产生或原有谱带的消失。     

辐照诱导的新雄性不育系过氧化物酶和脂酶同工酶分析

采用聚丙烯酰胺凝胶垂直板电泳法,对甘蓝型油菜细胞质雄性不育系Polima、Shan2A、Ogu和辐照处理的新雄性不育系Xin1和Xin2及其保持系Shan2B的种子进行了脂酶和过氧化物酶分析,结果表明:5个细胞质雄性不育系比保持系Shan2B多1条迁移率为0.45的脂酶(EST)谱带;Xin1、Shan2A和Polima各有4条过氧化物酶(POD)谱带,保持系缺少1条迁移率为0.61的POD谱带,推测这一同工酶的表达可能与雄性不育相关。     

Persistence of introduced Glomus intraradices in the field as influenced by repeated inoculation and cropping system

We studied the persistence of an introduced vesicular-arbuscular mycorrhizal (VAM) fungus in the field under the influence of a mycorrhizal host, a non-mycorrhizal host, and when the field was left fallow. There was a significantly greater, build-up of the mycorrhizal fungus in plots cropped with mycorrhizal hosts (finger millet or field beans) compared to plots cropped with a nonmycorrhizal host (mustard) or left fallow. Glomus intraradices, the introduced fungus, was further monitored by the electrophoretic mobility of the isozymes of malate dehydrogenase extracted from the resting spores of the fungus. The zymogram from G. intraradices spores showed three distinct isozyme bands: 1,3 and 7. A zymogram of malate dehydrogenase spores isolated from plots inoculated with G. intraradices for three seasons exhibited similar bands. Spores isolated from plots inoculated with G. intraradices for one or two seasons showed only one weak band, corresponding to isozyme band 7. The results indicated that the introduced fungus persisted in the field for only one season.     

Adaptability of hull-less barley varieties to different cropping systems and climatic conditions

Multilocation testing remains the main tool for understanding varietal responses to the environment. Here, Latvian and Norwegian hull-less and hulled barley varieties were tested in field experiments in Latvia and Norway in order to assess the varieties adaptability across environments (sites). Two Latvian (cv Irbe and cv Kornelija) and one Norwegian hull-less barley variety (cv Pihl) were tested along with one Latvian (cv Rubiola) and one Norwegian hulled barley variety (cv Tyra) under conventional and organic management systems. The grain yield, together with physical and chemical grain parameters were compared, and variety yield and protein stability determined. Overall, grain yield of hull-less barley varieties was significantly lower than for hulled barley varieties regardless of climatic conditions and management system. However, in the organic farming systems this difference between barley types was less pronounced. The hull-less barley varieties cv Pihl and cv Irbe, along with both hulled varieties, had good yield stability across environments and were well adapted to both cropping systems. Hull-less barley varieties tended to contain more protein and β -glucans than hulled barley varieties. Despite being bred for local conditions in Norway and Latvia, our study shows that all the varieties used may be successfully transferred across countries.     

Genetic diversity in European accessions of the Barley Core Collection as detected by isozyme electrophoresis

Genetic diversity in 79 European accessions of the Barley Core Collections was surveyed using isozyme electrophoresis. A total of 26 alleles were observed at the ten isozyme loci. All loci were polymorphic except Pgd-1 which was monomorphic. The comparison of the results with those of previous studies indicates that most of the alleles occurring in the European Barley are also observed in this set of the European Barley Core Collections. Only five alleles (Est-1 Al; Est-5 Ag, Te; Pgi-1 C and Ndh-2 B) were absent. Nine of 26 alleles were rare alleles, which were detected only in one or two accessions. Moreover, most of rare alleles were detected in 6-rowed winter barley. It is very important to include rare alleles for maximising the genetic variations in core collections. In the set of European Barley Core Collection, 6-rowed barley contained larger diversity than 2-rowed barley; winter type contained larger diversity than spring type. The cluster analysis separated 79 accessions into three major groups. Group I is more complex and comprised 2-rowed spring, 2-rowed winter and 6-rowed winter barley. In this group, 18 accessions in the cluster A and 14 accessions in the cluster B possessed identical genotypes as judged from the ten isozyme data. Principal coordinate analysis could not clearly separate the spring cultivars from the winter barley lines, as well as not separate 2-rowed from 6-rowed barley.     

Analysis of phenolic acids in barley by high-performance liquid chromatography

Phenolic acids from 30 barley varieties (combination of hulled/hulless/two-row/six-row/regular/waxy) were investigated by HPLC following four different sample treatments: (a) simple hot water extraction, (b) extraction after acid hydrolysis, (c) acid plus alpha-amylase hydrolysis, and (d) acid plus alpha-amylase plus cellulase hydrolysis treatments. The benzoic acid (p-hydroxybenzoic, vanillic, and protocatechuic acids) and cinnamic acid derivatives (coumaric, caffeic, ferulic, and chlorogenic acids) were identified, and some of the phenolic acids were quantified after each above-mentioned treatment. The data indicated that a combination of sequential acid, alpha-amylase, and cellulase hydrolysis treatments might be applicable for release of more phenolic acids from barley.     

Genotypic Variation in Color and Discoloration Potential of Barley‐Based Food Products

Barley has a variety of potential food uses. However, the dark gray color of the final products negatively affects consumer acceptability. We determined the discoloration potential of barley from different classes and genotypes, and evaluated the relationship of barley composition, total polyphenol content, and polyphenol oxidase (PPO) activity with discoloration potential of barley. Barley grains were abraded, milled into flour, and analyzed for composition, total polyphenol content, and PPO activity. Total polyphenol content of abraded barley, expressed as gallic acid %, was lowest in hulled proanthocyanidin‐free barley (0.02–0.04%), followed by hulled proanthocyanidin‐containing barley (0.11–0.18%), and hull‐less barley (0.19–0.26%). PPO activity of abraded kernels ranged from 62.1 units/g in hulled proanthocyanidin‐containing Baronesse to 116.5 units/g in hulled proanthocyanidin‐free CA803803. Dough sheet brightness (L* value) was the best indicator of discoloration potential of barley. Large variation in L* value of dough sheets was observed among different classes and among genotypes within classes. Brightness of dough sheets measured at 24 hr were significantly higher in hulled (65.3–78.1) than in hull‐less (59.0–63.9) barley, and within hulled barley, higher in proanthocyanidin‐free (72.2–78.1) than in proanthocyanidin‐containing (65.3–69.6) barley. Total polyphenol content significantly correlated with the discoloration potential of barley. Protein content and ash content also had a significant negative correlation with discoloration of dough sheets. The results indicated that polyphenol compounds may play a major role in discoloration potential of barley‐based products.     

Phytochemical and dietary fiber components in barley varieties in the HEALTHGRAIN Diversity Screen

Ten different barley varieties grown in one location were studied for their content of tocols, folate, plant sterols, alkylresorcinols, and phenolic acids, as well as dietary fiber components (arabinoxylan and beta-glucan). The samples included hulled and hull-less barley types and types with normal, high-amylose, and waxy starch. The aim was to study the composition of raw materials, and therefore the hulls were not removed from the hulled barleys. A large variation was observed in the contents of all phytochemicals and dietary fibers. Two varieties from the INRA Clermont Ferrand barley program in France (CFL93-149 and CFL98-398) had high content of tocopherols and alkylresorcinols, whereas the variety Dicktoo was highest in dietary fiber content and phenolics. Positive correlations were found between 1000 kernel weight, alkylresorcinols, and tocols, as well as between dietary fiber content and phenolic compounds. The results demonstrate that the levels of phytochemicals in barley can likely be affected by breeding and that the contents of single phytochemicals may easily be adjusted by a right selection of a genotype.     

大麦离体诱变效应的研究

以二稜皮大麦品种舟麦2号和秀四的幼胚及其愈伤组织为离体诱变材料,研究了γ射线不同剂量辐照后的离体培养反应、生理损伤及诱变效应。结果表明,用γ射线辐照离体大麦幼胚及其愈伤组织的适宜剂量是10—20Gy,MR_2代的突变频率可比常规诱变技术(300Gy γ射线辐照干种子)分别提高33.9％—82.1％和32.7％—229.6％;比离体培养技术分别提高84.0％—150.3％和82.4％—352.9％,而且仍可维持相对较好的培养反应。用30Gy辐照幼胚的诱变效果则可提高9—13倍,但严重抑制了离体培养物的再生能力,并导致了MR_1代严重的生理损伤。     

Estimation of Variability of Five Enzyme Systems Among Wild and Cultivated Species of <Emphasis Type="Italic">Trifolium</Emphasis>

The genus Trifolium comprises of 290 annual and perennial species of which the species such as T. repens, T. hybridum, T. pratense, T. ambiguum, T. resupinatum, T. alexandrinum are economically important. Boundaries between species in many cases have been difficult to define because of wide range of diversity caused by primary polymorphism. Hence, inter- and intraspecies variation in Trifolium, for zymogram pattern of five enzyme system was made to work out estimate of variability for isozymic banding pattern and get an insight into the species relationship. A total of 25 species represented by 134 accessions were compared for 5 enzymes viz. peroxidase, esterase, superoxide dismutase, acid phosphatase, and glutamate oxalo acetate transaminase using starch gel electrophoresis. Forty-six types of zymograms for Est isozyme pattern were observed amounting to 4.38 estimate of variability. The estimates of variability revealed maximum variation in T. resupinatum (4.24) followed with 3.02 in T. nigrescens. Estimate of variability for superoxide dismutase ranged from 0.46 to 2.67 among species amounting to 1.08 total variability across species. A total of 28 types of glutamate oxalo acetate transaminase zymograms were observed accounting for 2.48 estimate of variability. All but one band attributed to an estimate of variability of 1.43 in the genus for ACP and 16 different types of ACP zymograms were noticed. Highest variation for ACP was observed in T. resupinatum (4.53). Estimate of variation for peroxidase was 4.83 and 51 types of zymogram were observed. The species differed markedly for zymograms. The species distributed both in temperate and tropical parts like T. resupinatum had more variability as compared to cultivated species like T. alexandrinum and T. pratense. The rich variability present among these species can provide good source of gene transfer from wild to cultivated species which otherwise have no specific zymogram and exhibit low variability. The species sharing zymogram pattern for one or more enzymes with cultivated species were considered to have affinity and can further be utilized in attempting interspecific hybridization.