Foliar sprays against potato common scab: compounds related to 3,5-dichlorophenoxyacetic acid

In glasshouse tests against the soil-borne disease potato common scab (Streptomyces scabies), foliar sprays (0 · 9 mm) of several compounds inhibited symptom development as effectively as 3,5-D (3,5-dichlorophenoxyacetic acid). These compounds were of two main types: (1) compounds very similar in structure to 3,5-D, viz. 3,5-disubstituted phenoxyacetic acids in which the substituents were dibromo-, di(trifluoromethyl)- or any combination of bromo-, chloro- and iodo- except diiodo-; (2) compounds which could be metabolized to 3,5-D within the plant, viz. 4-(3,5-dichlorophenoxy)butanoic acid, 3,5-dichlorophenoxy-acetamide, 3,5-dichlorophenoxy-N,N-diethylacetamide and 2-(3,5-dichlorophenoxy)ethylamine. No compound of either type was significantly more effective than 3,5-D, and those which were as effective shared its effects on tuber yield, number and shape. About 30 other compounds related to 3,5-D were less effective or ineffective.     

Triterpenoid saponins from corms of Crocus sativus: Localization, extraction and characterization

A mixture of highly glycosilated triterpenoid saponins (CS5) isolated from the corm of Crocus sativus or saffron showed cytotoxic activity against HeLa tumoral cells. The main reverse phase HPLC fraction of this mixture (CS5-1) contains two new oleanane-type saponins, denominated Azafrine 1 (1) and Azafrine 2 (2). The bidesmosidic saponins were respectively characterized as (1) 3-O-β-d-glucopyranosiduronic acid echinocystic acid 28-O-β-D-galactopyranosyl-(1 → 2)-α-l-arabinopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 4)]-α-d-rhamnopyranosyl-(1 → 2)-[4-O-di-α-L-rhamnopyranosyl-3,16-dihydroxy-10-oxo-hexadecanoyl]-α-D-fucopyranoside and (2) 3-O-β-D-galactopyranosiduronic acid echinocystic acid 28-O-β-D-galactopyranosyl-(1 → 2)-α-L-arabinopyranosyl-(1 → 2)-[β-D-xylopyranosyl-(1 → 4)]-α-L-rhamnopyranosyl-(1 → 2)-[4-O-di-α-L-rhamnopyranosyl-3,16-dihydroxy-10-oxo-hexadecanoyl]-β-D-fucopyranoside. The surfactant properties of saponins, probably involved in the cytotoxic activity of CS5 and their exclusive localization in the external part or the corm, indicate their possible role as phytoprotectans. The similarity of their structural compositions to that of other triterpenoid saponins which are of special use in the pharmaceutical industry suggest a new application for C. sativus crops through the exploitation of corm for saponin extraction.     

Effects of α-, β-, γ- and ω-Gliadins on the Dough Mixing Properties of Wheat Flour

Gliadins were extracted from wheat and individual groups (α-, β-, γ-, ω-1 and ω-2) purified. The effects of the individual groups of gliadin on the mixing properties of doughs from low and high protein flours were measured on a 2-g Mixograph and a prototype microextension tester. The addition of all groups of gliadin resulted in a decrease in dough strength. The relative weakening effects were ω-1>ω-2≈α-≈β->γ- in the Mixograph, and γ->α-≈β-≈ω-2≈ω-1 in the Extensograph.     

Callus induction and in vitro plant regeneration of rice (Oryza sativa L.) under various conditions

The objective of the present study was to develop an effective protocol for optimum callus induction and complete plant regeneration for four varieties of rice (Oryza sativa L.) i.e., Super Basmati, Basmati-370, Basmati-371 and Fakhre Malakand. Calli were induced from mature seed scutelum. The Murashige and Skoog (MS) and Chu's N6 media containing hormone 2, 4-D (2, 4-Dichlorophenoxy acetic acid) in different concentrations were used for callus induction. Fakhre Malakand produced maximum calli on N6 media containing 3 mg L(-1) 2,4-D. while other three varieties showed maximum callus induction on N6 media containing 2.5 mg L(-1) 2,4-D. N6 media was found better than MS media for callus induction. For complete plant regeneration the calli of two varieties i.e., Basmati-370 and Basmati-371 were plated on N6 media containing different concentrations of NAA (1-Naphthalene acetic acid) and BAP (6-benzyl aminopurine). The maximum regeneration frequency (%) was observed on N6 media containing NAA 1 mg L(-1) and BAP 2.5 mg L(-1). It took 27-30 days for the callus to regenerate into a complete plant. Basmati-370 produced 4-7 plantlets per callus whereas Basmati-371 produced 4-8 plantlets per callus with regeneration frequencies of 61 and 69%, respectively.     

Elongation and insolubilisation of α-glucans by the action of Neisseria polysaccharea amylosucrase

Amylosucrase (E.C. 2.4.1.4) from Neisseria polysaccharea catalyses a transglycosylation reaction using sucrose as a glucose donor to synthesise an insoluble (1→4)-α-glucan, releasing fructose in the solution. If glycogen is used as a glucosyl unit acceptor, amylosucrase elongates polymer branches from their non-reducing ends. Testing of a large series of acceptors with various molar masses, glycosidic linkages, branching degrees and solubilities showed that chain elongation occurred only on polymers with (1→4)-α- or (1→4)-α- and (1→6)-α- linkages. Synthesis yields were better for completely soluble polymers (1.45 glucosyl units grafted per glucosyl unit for polymers with (1→4)-α- and (1→6)-α- linkages), than for partially soluble polymers (0.27–0.97 glucosyl units grafted per glucosyl unit for polymers with either (1→4)-α- linkages or (1→4)-α- and (1→6)-α- linkages). Elongation occurred randomly at the non-reducing ends of some external chains. Elongation of soluble branched molecules led to rapid gel formation favourable to gelation control inside suspensions and solutions. These polymers showed resistant starch contents (22% (w/w) to 57%) after elongation with amylosucrase.     

一种国外沉香中2-(2-苯乙基)色酮类化合物研究

为了了解一种国外沉香中的2-(2-苯乙基)色酮类化合物,采用多种色谱分离技术从该沉香的乙醇提取物中分离得到6个化合物,通过波谱学方法分别鉴定为：6-羟基-8-氯-2-[2-(4°-羟基苯基)乙基]色酮（1）,6-羟基-2-[2-(3°-甲氧基-4°-羟基苯基)乙基]色酮（2）,6-羟基-7-甲氧基-2-[2-(4°-羟基苯基)乙基]色酮（3）,沉香四醇（4）,5α,6β,7β,8α-四羟基-2-[2-(4°-甲氧基苯基)乙基]-5,6,7,8-四氢色酮（5）和6-羟基-2-[2-(3°-甲氧基-4°-羟基苯基)乙烯基]色酮（6）。化合物1为新的2-(2-苯乙基)色酮。对化合物2~6的细胞毒活性测试结果表明,化合物6对5株人体肿瘤细胞均表现出一定活性,其中对人慢性髓原白血病细胞K562和人肝癌细胞BEL-7402具有显著抑制活性,半数抑制浓度（IC₅₀）为2.87和 4.75 μg/mL,化合物2、3、5对5株人体肿瘤细胞表现出中等活性,IC₅₀范围为9.91~45.38 μg/mL。     

鹦歌岭土壤来源Streptomyces sp. YG-7的次生代谢产物及其α-葡萄糖苷酶抑制活性研究

为了研究原始热带雨林鹦歌岭土壤放线菌（Streptomyces sp.）YG-7的次生代谢产物及其α-葡萄糖苷酶抑制活性,采用多种柱色谱方法对土壤放线菌YG-7的发酵产物进行分离纯化得到9个化合物,经过波谱数据分析分别鉴定为：(1) 2-acetamido-5-chlorobenzamide, (2) cyclo (L-Pro-L-Leu), (3) 3,6-dibenzylidene-2,5-piperazinedione, (4) albonoursin, (5) (3Z,6S)-3-benzylidene-6-isobutylpiperazine-2,5-dione, (6) 3-hydroxy-2-methyl-4-pyrone, (7) isophthalic acid, (8) methyl 3-carbamoylbenzoate, (9) 2,3-dihydroxypropyl hexadecanoate. 其中,化合物1、7和8为新天然产物。活性测试结果表明化合物1、3~5和7~8对α-葡萄糖苷酶具有明显的抑制活性。     

Callogenic studies of Achyranthes aspera leaf explant at different hormonal combinations

With the objective to promote in vitro callus induction, leaf segments of Achyranthes aspera were inoculated on basal MS medium supplemented with 3.0% sucrose and 0.8% agar with different concentrations of 2,4-D alone and in combination with NAA, BAP, IAA, IBA and Zeatin. The explants were maintained in growth room at 25 +/- 1 degrees C and 16 h light cycle. The best callus induction was obtained with 2,4-D (1.0 and 2.0 mg L(-l)) in combination with NAA (0.5 mg L(-1)). Callus induction and good texture from leaf explant was also observed at 2,4-D with BAP. On these combinations morphologically, light green, soft, compact and non-embryogenic callus (Type III callus) was observed. While morphology of callus and callogenic response was poor at 2,4-D alone or in combination with other hormones at different concentrations.     

利用遗传同质的近等基因对研究水稻抗稻瘟病基因的产物

 应用经典遗传学方法构建了多个只有抗感基因之差，其他遗传背景相似的抗稻瘟病近等基因对， 它们的形态性状比较和过氧化物酶同工酶、过氧化物酶等电聚焦电泳带模式以及蛋白质双向电泳的图谱模式都说明每一组近等基因对有很高的同质程度，近等基因对不接种病原菌的双向电泳图谱中，pI 7.5～8.5， 分子量30～45 kDa区域的蛋白质亚基和稻瘟病的发生发展关系甚密，称该区为稻瘟病有关的蛋白质特异区，接种病原菌5 d后，近等基因对的双向电泳图谱中，蛋白质亚基变化同样发生在该特异区内。     

Growth optimization and organogenesis of Gerbera jamesonii Bolus ex. Hook f. in vitro

Regeneration potentials in Gerbera jamesonii Bolus ex. Hook f. from tissues culture system was studied using leaf, petiole and root explants. In vitro regeneration, callus induction and root formation were optimized by manipulation of growth regulators during organogenesis. Various kinds of plant growth regulators such as 6-Benzylaminopurine (BAP), alpha-Naphthalene acetic acid (NAA), 2, 4-Dichlorophenoxyacetic acid (2,4-D), Indole-3-acetic acid (IAA), Indole-3-Butyric acid (IBA), N6-[2-Isopentenyl]adenine (2iP), Kinetin and Zeatin were used to initiate cultures. These plant growth regulators were added to Murashige and Skoog medium in different combinations and concentrations. Adventitious shoots were obtained from petiole explants cultured on Murashige and Skoog (MS) medium supplemented with 2.0 mg L(-1) BAP and 0.5 mg L(-1) NAA. Effectiveness of shoot regeneration medium, type of growth regulator used and duration of induction period were investigated. Leaf explants cultured on MS medium supplemented with 1.0 mg L(-1) BAP and 2.0 mg L(-1) 2, 4-D showed the best results for callus induction. Root explants were found to be non-regenerative in all experiments conducted. Petiole segment was identified as the best explant for regeneration of this species. Regenerated plants were rooted on Murashige and Skoog basal medium. Plantlets were then transferred to field with 75% survival rate.     

玉米花药培养影响因素研究

采用36种玉米基因型材料,研究了基因型、培养基、接种前冷藏以及田间早期对雄穗注射一定浓度的2,4-D和在接种前用一定浓度的2,4-D浸泡雄穗对出愈率的影响。结果表明:在玉米培养基 N6(微量元素) 2,4-D2mg/L KT2mg/L 水解酪蛋白(CH)500mg/L 活性炭0.2% 糖12% 琼脂6.5g的诱导培养基中,36个基因型玉米中只有7个基因型能诱导出愈伤组织。其中博丰5号在接种前用4℃冷藏7d出愈率可增加3.71%;SB304在13～14叶期用2,4-D注射雄穗能有效提高其出愈率;金象4号雄穗在接种前用2,4-D浸泡,随着2,4-D浓度的增加或浸泡时间的加长,其出愈率都在增加。     

In vitro regeneration of Irvingia gabonensis by somatic embryogenesis

A productive genotype of Irvingia gabonensis were cultured in vitro for induction embryogenic calli, somatic embryogenesis and regeneration of plantlets. Fragments of young leaves were used as primary explants. Callogenesis was initiated by culture of explants during 30 days on Murashige and Skoog medium half strength (MS/2) supplemented with 1-6 mg L(-1) of 2,4-dichlorophenoxyacetic acid (2,4-D). The highest percentage of explants forming calli is 85.1% at 3 mg L(-1) of 2,4-D. Somatic embryos were obtained after a subculture of embryogenic calli during 60 days on MS/2 supplemented with 1-3 mg L(-1) of BAP. The highest percentage of embryogenic calli which differentiates somatic embryos is 63.8 +/- 2.3% at 1 mg L(-1) of 6-benzylaminopurine (BAP). The highest number of somatic embryos per callus which is 43.6 is obtained with 2 mg L(-1) of this phytohormone. When isolated from calli and sub-cultured during 30 days on MS/2 supplemented with 2 mg L(-1) of BAP, somatic embryos germinate with a highest percentage of 83%. The subculture of germinated somatic embryos on the same Basal Medium (BM) supplemented with 4 mg L(-1) of BAP and 2 mg L(-1) of Naphthalene Acetic Acid (NAA) during 80 days gives rise to the plantlets with 82.7 +/- 4.8% of success. With this combination, each plantlet has average length of 5.6 cm, bears 3.3 leaves and 7.2 roots with 1 or 2 pivoting roots. Plantlets acclimatized on a mixture sterilized soil/vermiculite at equal volume survive at 93%. Results of this study constitute a new way for a production of Irvingia gabonensis seedlings with pivoting root and they permit to arrest the difficulties of natural and horticultural reproduction.     

水稻矮化小穗基因DSP2的鉴定与克隆

[目的]水稻株高和穗型在产量形成中发挥着重要作用.鉴定与克隆水稻株高和穗型发育相关基因,可以丰富水稻株高穗型发育调控的分子机理,为分子设计育种奠定理论基础和提供基因资源.[方法]在粳稻日本晴T-DNA插入群体中筛选到矮化小穗突变体dsp2-D(dwarf and small panicle 2-Dominant),对其...     

从大豆幼胚诱导胚胎发生再生植株

采用MS基本培养基附加高浓度的生长素(2,4—D或NAA)成功地诱导了大豆(G.max)未成熟胚的体细胞胚胎发生。2,4—D的诱导效果明显优于NAA。细胞分裂素对体细胞胚胎发生有抑制作用。适宜的维生素B1浓度为0.4ppm。体细胞胚胎发生频率随蔗糖浓度(1.5—9％)的提高而降低。体细胞胚胎经历诱导、成熟和发芽三个阶段成功地发育成完整植株。再生植株移入土壤已经获得种子。     

2, 4-D Residues in tubers; Texture and respiration of potatoes in storage

Residues of 2, 4-D found in potato tubers ranged from 15 to 30 ppb at harvest when 2, 4-D was applied at the rate and time recommended for enhancement of color and control of tuber size. When used at higher rates and applied later, average residues reached 110 ppb. These residues did not include 2, 4-D bound to plant metabolites. In a single test, hydrolysis with aqueous acid resulted in a two to seven fold increase in 2, 4-D residues, suggesting a considerable portion of the 2, 4-D becomes combined with plant metabolites. Apparent respiration in storage of tubers from plants treated with 2, 4-D averaged 11% higher than tubers from plants not sprayed, but this was not great enough to be significant. Tubers of the same specific gravity from unsprayed plants and those sprayed with recommended rates of 2, 4-D were similar in texture.     

玉米幼胚组织培养体系优化

以5个骨干玉米自交系幼胚为材料, 研究幼胚大小、2, 4-D浓度、KT浓度对幼胚愈伤组织诱导及分化的影响。结果表明, 5个骨干玉米自交系均可诱导出愈伤组织, 但不同条件下诱导率存在显著差异。最适幼胚大小为2.0～3.0 mm, 因基因型不同而有所变化;2, 4-D浓度在1.0～3.0 mg/L有利于愈伤组织诱导, 同一材料不同2, 4-D浓度对胚性愈伤组织诱导率的影响具有显著差异, 不能以初级愈伤诱导率高低作为选择胚性愈伤诱导率的标准;KT可显著提高愈伤组织的分化率, 随着KT浓度的增加分化率呈先上升后下降的趋势, 最适KT浓度为1.0～2.5 mg/L。     

基本培养基及激素对野生一粒小麦幼胚培养的影响

为建立适于野生一粒小麦遗传转化的高效组培再生体系,以野生型一粒小麦幼胚为外植体,研究了MS、MSE3和N6三种基本培养基和激素对愈伤组织诱导、分化和成苗的影响。结果表明,愈伤诱导培养基以MES3为基本培养基并添加2.0mg·L~(-1) 2,4-D效果最佳,愈伤组织出愈率最高可达90.5%,胚性愈伤率为80.0%。愈伤组织分化过程在添加0.25mg·L~(-1) IAA的MS培养基中加入0.5mg·L~(-1) 6-BA分化效果最佳,分化率能达到50.7%,成苗率为26.5%。     

玉米幼胚愈伤组织诱导及再生

利用综3、87-1、郑58、昌7-2、137和K12等6个骨干自交系玉米幼胚进行愈伤组织诱导并建立再生体系。结果显示,2,4-D对玉米幼胚愈伤组织的诱导形成是必需的,浓度在2.0～2.5 mg/L;6-BA不利于愈伤组织的形成,但能促进幼胚直接长芽、长根,尤其以郑58最明显。材料综3、郑58、K12诱导愈伤组织比较容易,诱导率均≥85%;材料137和87-1表现中等,诱导率约在50%～60%;材料昌7-2表现最差,愈伤组织诱导率≤25%。     

2,4-D对大豆体细胞胚胎发生及增殖的影响

研究不同浓度的2,4-D对不同基因型大豆体细胞胚胎发生及增殖的影响.结果表明:不同基因型大豆体细胞胚胎发生率存在显著差异,在供试的6种基因型中,以CH21141和黑农40体细胞胚胎发生率最高,黑农35诱导率最低;大豆体细胞胚胎发生及继代增殖的最佳2,4-D浓度为10～20 mg·L~(-1),继代扩繁系数为3~n(n为继代培养次数).     

节节麦幼胚再生体系的建立

为建立高效的节节麦幼胚再生体系,以节节麦幼胚为外植体,通过正交设计,探索基本培养基、2,4-D、碳源、KT等因素对幼胚愈伤组织诱导、分化及植株再生效果的影响。结果表明,4种因素中,基本培养基对节节麦幼胚愈伤组织诱导的影响最显著(P0.05),2,4-D浓度对节节麦幼胚愈伤组织诱导也有显著影响(P0.05),添加3.0mg·L~(-1) 2,4-D的培养基诱导出的愈伤组织质量高,淡黄色,表面呈不规则颗粒状,质地致密,再生频率可以达到17.62%。KT浓度对节节麦愈伤分化影响最显著,基本培养基、2,4-D和碳源对节节麦幼胚愈伤分化均无显著影响。不同碳源对节节麦幼胚愈伤组织诱导和分化的影响均不显著,为节约成本可直接选用30g·L~(-1)蔗糖作为碳源。节节麦幼胚组织培养的最佳组合是:愈伤诱导培养基为MS培养基+3mg·L~(-1) 2,4-D+15g·L~(-1)蔗糖+15g·L~(-1)甘露醇,愈伤分化培养基为MS培养基+15g·L~(-1)蔗糖+15g·L~(~(-1))甘露醇+1.0mg·L~(-1) KT。