《江西腐植酸》一九八一年1—4期总目录

·专题讨论· J留植酸的植物生长调节作用1(1) 腐植酸的胶体化学性质1(3) 对应用腐植酸类物质防治作物病虫害 的一些看法1(12) 腐植酸应用于临床值得重视的几个问 题1(18) 腐植唆在医药方面的应用概况2(1) 国内外腐植酸类物质综合利用的动向2(4)关于腐肥的肥效及其经济效果的调查2(11)腐植唆类物质与氮肥增效剂3(1)对试制瓷用腐钠滚压成型添加剂的初步探讨3(9)加强丝础研究,促进腐植酸工业利用4(1)-腐植骏结构与植物刺激作用4(6) ·全国腐植酸工业应用座谈会专题材料·腐植酸盐减水剂研制总结4(14)使用腐值酸盐减水剂技术经济效果显著4(34)…     

腐植酸类物质对大庆盐碱土地区草场改良效果的研究

本文通过对大庆地区盐碱土改良进行研究，将一定量腐植酸类物质(黑龙江五常张家湾草炭、萝北的褐煤、七台河风化煤)施入耕层(0～20cm)。试验表明：腐植酸类物质在改良黑龙江省大庆地区盐碱土的理化性质有明显效果：pH值降低；全盐量降低；土壤碱化度(ESP)下降；土壤总碱度(HCO3^-与C03^2-含量之和)降低；土壤密度下降；土壤有机质有所增加。另外，该盐碱土区的牧草(星星草)的增产效果显著，能够促进植物养分吸收，刺激植物生长，提高抗逆性。     

不同药剂复配对南方根结线虫增效作用

[目的]筛选对南方根结线虫高效低毒的药剂。[方法]采用浸泡杀线虫法测定9种药剂对南方根结线虫的毒力,选活性较高的单剂进行交互复配,测定其联合毒力。[结果]甲氨基阿维菌素苯甲酸盐对2龄幼虫和卵囊的毒力最强,LC50值分别为2.51、10.50 mg/L;甲氨基阿维菌素苯甲酸盐与噻唑膦复配的共毒系数为141.59,阿维菌素与噻唑膦复配的共毒系数为159.37。[结论]单剂以甲氨基阿维菌素苯甲酸盐活性最高,复配剂以噻唑膦与阿维菌素、甲氨基阿维菌素苯甲酸盐复配效果最佳。     

抗旱剂一号(HCF—1)对农作物的抗旱增产作用示范

一、引言腐植酸是具有多功能的有机复合体,富含醌基和酚羟基,分子量较低,易被植物吸收运转于体内增强酶的活性,而酶的活性又和水份生理密切相关。国外研究,腐植酸类物质对植物生长发育和改善土壤条件有重要作用,这种作用在不良的外界影响下(如旱、涝、寒、热)更为明显,对这种现象称之为“腐植质效应”(Flaig1974)。全国腐肥     

沈阳地区大型真菌对不同种类线虫的毒力

从沈阳市东部山区及沈阳农业大学周边环境采集到94种野生大型真菌,并将采集到的大型真菌制成浸提液,以胞囊线虫、根结线虫、腐烂茎线虫、水稻干尖线虫和小杆线虫为靶标,初步测定了大型野生真菌对5种不同种类线虫的活性作用.研究结果表明,不同菌株对不同种类线虫毒力作用具有选择性差异.对其中一种线虫的校正死亡率达到70%以上的有12种大型野生真菌,有7株菌对两种以上线虫校正死亡率达到70%.菌株F70对南方根结线虫毒杀作用最高为84.13%,菌株F92对大豆胞囊线虫毒杀作用最高为95.84%,具有选择毒性,菌株F25对腐烂茎线虫毒杀作用最高为75.91%,菌株F81对小杆线虫毒杀作用最高为75.77%,而对其他植物线虫活性差,菌株F6对水稻干尖线虫毒杀作用最高为81.82%.初步鉴定有效菌株F92为鬼伞属,F70为香菇属,F6为伞菌属,F25为伞菌属和F81为侧耳属.     

从农副产品制取类腐植酸物质的研究

一、从农副产品制取类腐植酸物质的研究概况 人类对于腐植酸类物质的利用可以追溯到始于有机肥料的利用。“落叶归根”就是植物叶片经微生物分解产生供根系吸收的营养物质(其中就有腐植酸)的过程。(1916)对植物残体——森林落叶层和草本植物——产生腐植物质的研究中指出,各种不同的植物性物质都可以是腐植质的来源。     

腐植酸类物质是土壤健康的重要保障

腐植酸类物质是一种具有复杂结构的功能大分子,其种类和数量对土壤质量、土壤可持续利用具有重要作用。本文从土壤肥力质量、土壤环境质量、土壤健康质量3个方面综合阐述了腐植酸类物质对于保障和维持土壤质量健康、保护人类和动植物健康的重要作用和意义,并对今后的研究方向提出了若干建议。     

混配增效剂对菌线克增效作用

菌线克是一种用于防治线虫的新型农用抗生素,以根结线虫为靶标,通过室内毒力测定6种增效剂(TPP、DEM、PEG、NT、H3BO3、吐温-20)对菌线克的增效作用,筛选出3种增效剂单剂(TPP、PEG、H3BO3)的增效效果明显.经二元复配及最佳配伍筛选,测定混用增效剂对菌线克的增效作用,H3BO3和PEG以体积比1:1比例混合增效作用最好,增效比为5.25.     

硝基腐肥在水稻,小麦蔬菜上的效果

我所根据农牧渔业部在成都召开的“全国主要省市一九八三年腐植酸类物质在农业生产中应用的试验、示范、推广总结座谈会”的要求,和四川省化工厅川腐字(84)第020号的通知,于1984年对成都磷肥厂生产的硝基腐植酸氮磷钾肥(下简称硝基腐肥)在不同土壤,主要作物上进行了试验,以明确其增产效果,为化工部门开发肥料新品种和农业生产上推广使用该肥料提供科学依据。     

应用煤炭腐植酸作为酶脲抑制剂的试验研究初探

应用不同方法,对来自东北、新疆、广东、云南、山西等地不同煤源所制成的共18种腐植酸类物质,对脲酶活性的抑制作用,进行了初步筛选。其结果为:在本试验条件下,除HA_1(新疆风化煤HA—K),HA_5(山西灵石化煤HA—N—P—K),HA_7(云南褐煤HA—Na)及HAs(东北泥炭HA—Na)对脲酶无抑制作用外,其余14种煤炭腐植酸类物质,均表现了不同程度的抑制作用。其中,与参比抑制剂—对苯二酚抑制效果接近的有HA_4(山西灵石风化煤NHA),HA_(13)(云南褐煤NHA—Fe_1),HA_(14)(云南褐煤NHA—Fe_2),HA_(15)(山西灵石风化煤NHA—Na),HA_(11)(东北泥炭HA—U—Fe)以及HA_(18)(山西代县褐煤NHA—U—Fe)六种。 初步表明:应用某些腐植酸类物质作为尿酶抑制剂是可行的。由于煤炭腐植酸原料丰富,价格低廉,加工简便,对土壤、植物无污染,避免了现有各种抑制剂的不足之处,可望成为脲酶抑制剂,为长效尿素的生产提供新的途径。     

The Plant Sesquiterpene Nootkatone Efficiently Reduces Heterodera schachtii Parasitism by Activating Plant Defense

Plant parasitic nematodes, including the beet cyst nematode Heterodera schachtii, constitute a devastating problem for crops worldwide. The limited availability of sustainable management options illustrates the need for new eco-friendly control means. Plant metabolites represent an invaluable source of active compounds for the discovery of such novel antagonistic agents. Here, we evaluated the impact of eight plant terpenoids on the H. schachtii parasitism of Arabidopsis thaliana. None of the metabolites affected the plant development (5 or 10 ppm). Nootkatone decreased the number of adult nematodes on A. thaliana to 50%, with the female nematodes being smaller compared to the control. In contrast, three other terpenoids increased the parasitism and/or female size. We discovered that nootkatone considerably decreased the number of nematodes that penetrated A. thaliana roots, but neither affected the nematode viability or attraction to plant roots, nor triggered the production of plant reactive oxygen species or changed the plant’s sesquiterpene profile. However, we demonstrated that nootkatone led to a significant upregulation of defense-related genes involved in salicylic and jasmonic acid pathways. Our results indicate that nootkatone is a promising candidate to be developed into a novel plant protection agent acting as a stimulator of plant immunity against parasitic nematodes.     

Quantitative bioassay for chemotaxis with plant parasitic nematodes

A simple, flexible, and quantifiable bioassay for the attraction or repulsion of plant parasitic nematodes to or from root fractions or pure substances is described. Accurate gradients of volatile and nonvolatile substances can be measured and established. The method entails placing the nematodes in narrow agarose tracks such that their movement is essentially linear and the distance a population has traveled away or toward a given substance can be monitored with time. Plastic plates, each containing 10 such tracks, are described. The method is illustrated with second-stage larvae ofMeloidogyne incognita and a volatile attractant and nonvolatile repellent fraction obtained from cucumber roots.     

Nematode-antagonistic trichothecenes from Fusarium equiseti

A strain of the fungus Fusarium equiseti isolated from soybean cyst nematode secretes nematode-antagonistic compounds. Bioassay-guided fractionation of an extract of the culture broth was undertaken to identify the compounds. Fractions were assayed for activity against a root-knot nematode (Meloidogyne incognita), a plant pathogen that attacks the roots of numerous plant species. Two trichothecene compounds were isolated that inhibited egg hatch and immobilized second-stage juveniles of this nematode: 4,15-diacetoxy-12,13-epoxy-3,7-dihydroxytrichothec-9-en-8-one (4,15-diacetylnivalenol) and 4,15-diacetoxy-12,13-epoxy-trichothec-9-en-3-ol ( diacetoxyscirpenol). This is the first published report of these compounds affecting plant-parasitic nematodes.     

Ozonated Nutrient Solution Treatment as an Alternative Method for the Control of Root-Knot Nematodes in Soilless Cultivation

ABSTRACT

Root-knot nematodes (Meloidogyne incognita) are plant parasitic worms that widely influence the agricultural production including soilless cultivation. In this study, we investigated the inactivating effect of ozonated nutrient solution on the root-knot nematode juveniles in both nutrient solution and substrate, as well as the in vitro egg hatching. The results showed that twice ozonation treatments with dissolved ozone concentration (DOC) at 0.5 mg/L resulted in a mortality at 90.8% for in vitro study. DOC of 4.0 mg/L with three treatment repeats in the substrate experiment resulted in a mortality at 88.3%. Our results imply that the application of ozonated nutrient solution might be a feasible method in soilless cultivation for the control of root-knot nematodes. In practical application, ozonation treatment should be conducted with appropriate DOC and treatment repeats.     

Novel Functions of the Fatty Acid and Retinol Binding Protein (FAR) Gene Family Revealed by Fungus-Mediated RNAi in the Parasitic Nematode,Aphelenchoides besseyi

RNA interference (RNAi) is a powerful tool for the analysis of gene function in nematodes. Fatty acid and retinol binding protein (FAR) is a protein that only exists in nematodes and plays an important role in their life activities. The rice white-tip nematode (RWTN), Aphelenchoides besseyi, is a migratory endoparasitic plant nematode that causes serious damage in agricultural production. In this study, the expression levels of eight RWTN genes were effectively decreased when RWTN was fed Ab-far-n (n: 1–8) hairpin RNA transgenic Botrytis cinerea (ARTBn). These functions of the far gene family were identified to be consistent and diverse through phenotypic changes after any gene was silenced. Such consistency indicates that the body lengths of the females were significantly shortened after silencing any of the eight Ab-far genes. The diversities were mainly manifested as follows: (1) Reproduction of nematodes was clearly inhibited after Ab-far-1 to Ab-far-4 were silenced. In addition, silencing Ab-far-2 could inhibit the pathogenicity of nematodes to Arabidopsis; (2) gonad length of female nematodes was significantly shortened after Ab-far-2 and Ab-far-4 were silenced; (3) proportion of male nematodes significantly increased in the adult population after Ab-far-1, Ab-far-3, and Ab-far-5 were silenced, whereas the proportion of adult nematodes significantly decreased in the nematode population after Ab-far-4 were silenced. (4) Fat storage of nematodes significantly decreased after Ab-far-3, Ab-far-4, and Ab-far-7 were silenced. To our knowledge, this is the first study to demonstrate that Ab-far genes affect sex formation and lipid metabolism in nematodes, which provides valuable data for further study and control of RWTNs.     

Heterodera schachtii Nematodes Interfere with Aphid-Plant Relations on Brassica oleracea

Aboveground and belowground herbivore species modify plant defense responses differently. Simultaneous attack can lead to non-additive effects on primary and secondary metabolite composition in roots and shoots. We previously found that aphid (Brevicoryne brassicae) population growth on Brassica oleracea was reduced on plants that were infested with nematodes (Heterodera schachtii) prior (4 weeks) to aphid infestation. Here, we examined how infection with root-feeding nematodes affected primary and secondary metabolites in the host plant and whether this could explain the increase in aphid doubling time from 3.8 to 6.7 days. We hypothesized that the effects of herbivores on plant metabolites would depend on the presence of the other herbivore and that nematode-induced changes in primary metabolites would correlate with reduced aphid performance. Total glucosinolate concentration in the leaves was not affected by nematode presence, but the composition of glucosinolates shifted, as gluconapin concentrations were reduced, while gluconapoleiferin concentrations increased in plants exposed to nematodes. Aphid presence increased 4-methoxyglucobrassicin concentrations in leaves, which correlated positively with the number of aphids per plant. Nematodes decreased amino acid and sugar concentrations in the phloem. Aphid population doubling time correlated negatively with amino acids and glucosinolate levels in leaves, whereas these correlations were non-significant when nematodes were present. In conclusion, the effects of an herbivore on plant metabolites were independent of the presence of another herbivore. Nematode presence reduced aphid population growth and disturbed feeding relations between plants and aphids.     

Rapid and Visual Detection of Heterodera schachtii Using Recombinase Polymerase Amplification Combined with Cas12a-Mediated Technology

Heterodera schachtii is a well-known cyst nematode that causes serious economic losses in sugar beet production every year. Rapid and visual detection of H. schachtii is essential for more effective prevention and control. In this study, a species-specific recombinase polymerase amplification (RPA) primer was designed from a specific H. schachtii sequence-characterized amplified region (SCAR) marker. A band was obtained in reactions with DNA from H. schachtii, but absent from nontarget cyst nematodes. The RPA results could be observed by the naked eye, using a lateral flow dipstick (LFD). Moreover, we combined CRISPR technology with RPA to identify positive samples by fluorescence detection. Sensitivity analysis indicated that 10⁻⁴ single cysts and single females, 4⁻³ single second-stage juveniles, and a 0.001 ng genomic DNA template could be detected. The sensitivity of the RPA method for H. schachtii detection is not only higher than that of PCR and qPCR, but can also provide results in <1 h. Consequently, the RPA assay is a practical and useful diagnostic tool for early diagnosis of plant tissues infested by H. schachtii. Sugar beet nematodes were successfully detected in seven of 15 field sugar beet root samples using the RPA assay. These results were consistent with those achieved by conventional PCR, indicating 100% accuracy of the RPA assay in field samples. The RPA assay developed in the present study has the potential for use in the direct detection of H. schachtii infestation in the field.     

Suppression of plant parasitic nematodes in the chinampa agricultural soils

Soil from the chinampa agricultural system in the Valley of Mexico suppressed damage by plant-parasitic nematodes to tomatoes and beans in greenhouse and growth chamber trials. Sterilization of the chinampa soil resulted in a loss of the suppressive effect, thereby indicating that one or more biotic factors were responsible for the low incidence of nematode damage. Nine organisms were isolated from chinampa soil, which showed antinematodal properties in culture. Naturally occurring populations of plant-parasitic nematodes were of lower incidence in chinampa soil than in Chapingo soil.     

Phytoecdysteroids: A Novel Defense Against Plant-Parasitic Nematodes

The phytoecdysteroid, 20-hydroxyecdysone (20E), is a major molting hormone of invertebrates, possibly including nematodes. As 20E is inducible in spinach, the defensive role against plant-parasitic nematodes was investigated. The effects of direct application on nematodes was assessed by treating cereal cyst nematode, Heterodera avenae, juveniles with concentrations of 20E from 8.2 x 10(-8) to 5.2 x 10(-5) M before applying to Triticum aestivum growing in sand. H. avenae, Heterodera schachtii (sugarbeet cyst nematode), Meloidogyne javanica (root-knot nematode), and Pratylenchus neglectus (root lesion nematode) were treated with 5.2 x 10(-5) 20E and incubated in moist sand. To test the protective effects of 20E in plants, the latter three nematodes were applied to Spinacia oleracea in which elevated concentrations of 20E had been induced by methyl jasmonate. Abnormal molting, immobility, reduced invasion, impaired development, and death occurred in nematodes exposed to 20E either directly at concentration above 4.2 x 10(-7) M or in plants. Phytoecdysteroid was found to protect spinach from plant-parasitic nematodes and may confer a mechanism for nematode resistance.