枣茎段再生体系建立的研究

以‘骏枣’茎段为试验材料,通过组织培养技术的应用,研究影响茎段不定芽再生的主要因素。通过试验,选择出不定芽再生的适宜条件,建立枣茎段的高频再生系统,为基因工程技术在枣上的应用奠定良好基础。试验结果表明：茎段最佳取材阶段为5月中旬;最好的灭菌方法是间歇性灭菌处理;对内生菌抑制效果最好的抗生素是添加480 mg/L青霉素;茎段在培养基中的插入方式以竖直插入培养基方式接种,效果最好;在培养基1/2MS +6-BA 2.0 mg/L + IBA 0.5 mg/L上,不定芽再生效果最好。     

阜平大枣无芽茎段再生不定芽的初步研究

以MS为基本培养基,幼嫩的阜平大枣无芽茎段为试材,研究了灭菌时间、暗培养、以及植物生长调节剂对无芽茎段诱导不定芽再生的影响。结果表明：无芽茎段以灭菌8-10分钟为宜,暗培养21天最佳,在MS基本培养基上附加6-BA 1.0mg.L-1,,IBA 0.1mg.L-1再生率和平均出芽数显著高于其它处理, 分别为85.42%和 3.23,而且不定芽经培养后生长成枣头一次枝。     

美洲黑杨与大青杨杂种无性系离体培养和叶片再生体系的建立

以美洲黑杨与大青杨杂种(Populus deltoids Bartr.×Populus ussuriensis Kom.)无性系的茎段作为外植体,研究了杂种无性系的离体培养及叶片再生体系,探讨了不同激素组合对杂种无性系不定芽的诱导、分化、增殖以及生根的影响。结果表明：杂种无性系茎段的最佳消毒时间为5 min;最佳分化培养基为MS + 6-BA 2.0 mg/L + NAA 0.1 mg/L + ZT 0.5 mg/L;MS + 6-BA 0.5 mg/L + NAA 0.05 mg/L培养基可对不定芽实现增殖与复壮;最佳生根培养基为MS + NAA 0.3 mg/L。5个杂种无性系中,无性系177的分化能力最强;叶片近轴面向上放置培养,其不定芽再生能力显著高于叶片近轴面向下放置培养;叶片、茎段及根段的分化能力大小依次为叶片>茎段>根段。本研究优化了美洲黑杨与大青杨杂种的组织培养体系,为杂种无性系快速繁殖和遗传转化研究奠定了基础。     

濒危植物太行菊组织培养及快繁技术研究

研究旨在建立一种珍惜濒危植物太行菊的高效再生方法,为工厂化生产提供理论基础。以MS为基本培养基,用不同激素组合对太行菊无菌苗的叶片和茎段离体培养及植株再生、炼苗移栽等过程进行研究。结果表明,太行菊的叶片分化不定芽比茎段难,茎段最适合作为外植体进行愈伤组织的诱导及不定芽分化;筛选出了最佳培养基MS+6-BA 1.0 mg/L+NAA 0.1 mg/L,在此培养基中,茎段外植体可一步成苗,不需转换培养基即可完成愈伤组织的诱导分化及不定芽增殖过程;最佳生根培养基为1/2MS+NAA 0.2 mg/L;再生苗在花园土中移栽成活率可达80%。研究简化了培养流程,建立了太行菊一步式高效再生体系。     

桃叶卫矛茎段愈伤组织诱导及不定芽再生体系的建立

为完善及优化桃叶卫矛组培繁殖再生体系,解决以腋芽萌发为再生途径进行组培增殖时增殖系数小的问题,以桃叶卫矛幼嫩茎段为材料,分别用20%的次氯酸钠和0.10%的升汞进行消毒处理,处理时间分别为8、10、12 min获取其消毒最佳方案;以桃叶卫矛茎段为材料,通过调节6-BA和NAA浓度,诱导桃叶卫矛茎段产生愈伤组织;以桃叶卫矛愈伤组织为材料,采用6-BA和NAA正交试验诱导产生不定芽;以桃叶卫矛不定芽为材料,调节6-BA和NAA浓度,提高继代增殖系数;以桃叶卫矛继代增殖苗为材料,调节IBA和NAA浓度,获取桃叶卫矛生根苗。研究结果表明：（1）桃叶卫矛幼嫩茎段消毒最佳方案为20%的次氯酸钠处理12 min,污染率2%;（2）茎段愈伤组织诱导最佳培养基为1.0 mg/L 6-BA+ 0.10 mg/L NAA,诱导率80.00%;（3）不定芽诱导最佳培养基为0.5 mg/L 6-BA+ 0.10 mg/L NAA,诱导率91.11%;（4）继代增殖最佳培养基为MS+ 1.0 mg/L 6-BA+ 0.10 mg/L NAA,增殖系数6;（5）生根培养最佳培养基为1/2MS+ IBA 0.3 mg/L,生根条数平均为5条。本研究利用桃叶卫矛无芽茎段诱导出愈伤组织,并将继代增殖系数提高至6,且完成了桃叶卫矛组培再生体系的优化。     

马齿苋离体培养再生体系的建立

以马齿苋幼嫩叶片和茎段为试验材料,对外植体灭菌、愈伤组织诱导、不定芽分化和试管苗生根的最佳条件进行研究,以期建立马齿苋再生技术体系,并为马齿苋的规模化繁殖和遗传改良等研究奠定基础。结果表明,最佳外植体灭菌方法为：用0.1%的升汞溶液浸泡8 min;最佳愈伤组织诱导培养基为MS+2,4-D 0.5 mg/L+6-BA 0.5 mg/L;最佳不定芽分化培养基为MS+6-BA 5.0 mg/L+NAA 0.4 mg/L;最佳生根培养基为1/2MS+IBA 2.0 mg/L。     

唐古红景天愈伤组织诱导及植株再生

为解决唐古红景天种质资源短缺问题,本研究建立了唐古红景天愈伤组织诱导及再生体系。以唐古红景天幼嫩的叶片、茎段和根为外植体,筛选出最优的外植体灭菌处理方法;探索愈伤组织诱导和增殖,不定芽诱导和扩增的最佳激素配比;观测不定芽的生根情况以及再生苗生长状态。结果表明：唐古红景天诱导愈伤组织的最佳外植体为叶片,愈伤组织诱导的培养基为MS₀+1.0 mg/L 6-BA+0.1 mg/L NAA,诱导率为85.37%;最佳愈伤组织增殖的培养基为MS₀+0.5 mg/L 6-BA+0.5 mg/L NAA,增殖率为62.5%;最佳不定芽诱导、扩增的培养基为MS₀+2.0 mg/L 6-BA+0.5 mg/L NAA,诱导率为66.67%;不定芽在1/2MS生根诱导培养基中的生根率为42.5%,再生苗移栽于混合基质(泥炭∶珍珠岩∶蛭石=2∶1∶1)成活率为24.9%。该研究为唐古红景天种质资源的保存及人工栽培提供了有效的技术参数。     

野生软枣猕猴桃组织培养及褐变处理

以野生软枣猕猴桃嫩芽、幼嫩叶片以及茎段作为外植体,研究野生软枣猕猴桃组织培养整个过程,以建立快速高效的野生软枣猕猴桃再生体系。结果表明：最适宜的诱导叶片、茎段愈伤组织的培养基分别为MS+0.5 mg/L 6-BA+1.0 mg/L NAA和MS+0.5 mg/L 6-BA+0.1 mg/L NAA;诱导出愈伤组织在MS+0.6 mg/L 6-BA+0.05 mg/L NAA培养基上能很好地分化不定芽苗;诱导幼芽产生丛生芽的培养基为MS+1.0 mg/L 6-BA+0.1 mg/L NAA;较适宜的生根培养基为1/2MS。愈伤组织继代中发现细胞生长素NAA可以防止愈伤褐化。在愈伤组织分化中,发现将分化出的芽苗再次愈伤化,可以提高分化率。     

黄檗茎段不定芽分化过程中生理生化指标变化研究

以黄檗茎段为外植体,研究其不定芽分化过程中生理生化指标的变化。将黄檗无菌苗的茎段接种到MS+1.5 mg/L BA+0.5 mg/L NAA+20 g/L葡萄糖的培养基上,于20天左右大量形成不定芽,30天左右形成小苗。通过比色法,对茎段不定芽再生过程的生理生化指标测定表明,在不定芽形成过程中,SOD酶活性呈现出逐渐下降的趋势,而其他2种抗氧化酶（CAT和POD）活性、可溶性蛋白及可溶性糖含量在不定芽形成的高峰期之前均呈不同程度的上升趋势,随后则呈下降趋势。实验表明,抗氧化酶活性,可溶性蛋白及可溶性糖含量与不定芽再生有着明显的相关性。     

皇家夏天葡萄离体叶片再生体系的建立

叶片再生效率的高低直接影响目的基因转化的成功率,为建立稳定、高效的葡萄离体叶片不定芽再生体系,以优良无核葡萄品种皇家夏天为试材,取试管苗顶端1￣3叶位幼嫩叶片,研究了基本培养基成分、生长调节物质的种类和浓度、碳源等因素对叶片不定芽再生的影响。结果表明:供试WPM、1/2MS、B5和NN694种基本培养基,均可诱导其叶片再生不定芽,差异不显著;碳源以添加10￣20g/L的葡萄糖或食用白砂糖较好;培养基中附加3.0mg/L的6-BA与0.05mg/L的IAA配比利于出芽和成苗,应用TDZ虽出芽较多,但芽丛多畸形、出苗困难,不宜使用。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Variation in forage grasses as hosts of the root-knot nematode Meloidogyne naasi (Franklin) and selection for resistance in ryegrass

Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Current and future strategies in breeding lentil for resistance to biotic and abiotic stresses

Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed.