THE PERSISTENCE AND MOVEMENT OF FLUORODIFEN IN SOILS AND PLANTS

Summary. Miller clay and Lufkin sandy loam soils were treated with fluorodifen (4-nitrophenyl 2-nitro-4-trifluoromethylphenyl ether) at 3–4 and 5 kg/ha. The disappearance was monitored using electron-capture gas chromatography. Less than 10% of the herbicide remained 6 months after application. Persistence was increased by incorporation in the loam but not in the clay soil. Little leaching was detected in either soil. Fluorodifen was applied to both roots and leaves of soybean (Glycine max (L.) Merr.), grain sorghum (Sorghum vulgare Pers.), peanut (Arachis hypogaea L.) and morning glory (Ipomoea purpurea L.). The herbicide was absorbed by the treated tissue, but limited trans-location into other plant parts was detected by gas chromatography, autoradiography and liquid scintillation spectrometry. Following root application, higher concentrations of fluorodifen were found in the lower stems of morning glory and grain sorghum than in other species. La persistance et la migration du fluorodifene dans divers sols et plantes Résumé. De I'argile de Miller et des sols sablo-limoneux de Lufkin ont été traités avec du fluorodiféne (4-nitrophényl 2-nitro-4-trifluorométhylphényl éther) à 3, 4 et 5 kg/ha. La degradation a été suivie en utilisant la chromatographic en phase gazcuse avec détecteur à capture d'électrons. Aprés 6 mois d'application il ne fut détecté que moins de 10% de l'herbicide. La persistance fut accrue par l'incorporation dans le sol limoneux mais non dans le sol argileux; il ne fut mis en évidence qu'un faible lessivage dans les deux sols. Le fluorodifene fut appliquéà la fois sur les racines et sur les feuilles du soja (Glycine max (L.) Merr.), le sorgho à grains (Sorghum vulgare Pers.), l'arachide (Arachis hypogaea L.) et le volubilis (Ipomoea purpurea L.). L'herbicide fut absorbs par les tissus traites, mais il ne fut décelé qu'une migration limitée dans les autres parties de la plante, au moyen de la chromatographie en phase gazeuse, de l'autoradiographie, et de la spectrométrie à scintillation liquide. A la suite d'application par les racines, les concentrations de fluorodifene constatées dans les tiges basses du volubilis et dans le sorgho à grain furent supérieures à celles trouvées dans les autres espéces. Persistenz und Translokation von Fluorodifen in Böden und Pflanzen Zusammenfassung. Miller-Ton und Lufkin-Lehmboden wurden mit 3,5 und 5 kg/ha Fluorodifen (4-NitrGphenyl 2-nitro-4-trifluoromethyIphenylather) behandelt. Der Verlust der Aktivsubstanz wurde mit Hilfe der Elektroneneinfang-Gaschromatographic bestimmt. Sechs Monate nach der Behandlung waren weniger als 10% der ursprünglich ausgebrachten Aktivsubstanz noch nachweisbar. Die Persistenz war im Lehmboden, nicht jedoch im Tonboden, durch Inkorporation erhöht; in keinem Boden war nennens-werte Einwaschung zu beobachten. Fluorodifen wurde bei Sojabohnen (Glycine max (L.) Merr.), Körner-Hirse (Sorghum vulgare Pers.), Erdnuss (Arachis hypogaea L.) und Ipomoea purpurea L. sowohl über das Blatt als auch über die Wurzel angewandt. Das Herbizid wurde in das brhandelte Gewebe aufgenommen. Es erfolgte jedoch nur cine geringe Translokation in andere Pflanzenteile, wie die Untersuchung mit Hilfe der Gaschromatographic, Autoradio-graphic und Flüssigkeits-Scintiliations-Spectrometrie ergab. Nach Wurzelapplikation wurden in den unteren Sprossteilen von Ipomoea purpurea und Sorghum vulgare grössere Fluorodifen-Konzentrationen gefunden als bei den anderen Arten.     

THE RELATIONSHIP BETWEEN THE HERBICIDAL EFFECT OF 2,6-DICHLOROBENZONITRILE AND ITS PERSISTENCE IN THE SOIL

Summary. A series of experiments with 2,6-dichlorobenzonitrile is described. It is demonstrated that 2,6-DBN is highly phytotoxic when applied as a soil drench or preemergence spray in the greenhouse, but measurement of crop and weed responses in the field, accompanied by quantitative assessment of the chemical residues in the soil, indicates that the persistence of 2,6-DBN following surface application is short under both tropical and temperate (winter) conditions. It is, however, extended from a few days to several weeks if the chemical is incorporated into the soil immediately after application. Under tropical conditions the effect of 4 lb/ac applied to the surface is roughly equated to 2 lb/ac immediately watered-in, 1.5 lb/ac immediately raked-in, or 1 lb/ac both watered- and raked-in, and a delay of 4 hours between application and incorporation is shown to reduce the effectiveness of the chemical by about half. The lack of persistence of 2,6-DBN when applied to the soil surface, and the modifying influence of soil incorporation and watering is attributed to its high vapour pressure (5 × I0⁻⁴ mm Hg at 20° C) and its relatively low solubility in water (20 ppm at 25° C).
Le rapporl entre l'activité herbicide du 2,6-dichlorobenzonitrile et sa persistance dans le sol     

THE MOVEMENT OF PARAQUAT IN PLANTS

Summary. A qualitative study of the movement of the herbicide paraquat from droplets applied to leaves of tomato plants, using ¹⁴C-methyl-labelled and ¹⁴C-ring-labelled paraquat dichloride and di(methylsulphate), has shown that it moves in the xylem with the transpiration stream. The chemical is as well transported from young leaves as from mature ones, and will move through a steam-ringed petiole. The enhancement of the amount of paraquat transported from the treated leaves which occurs when treated plants are kept in darkness for a period following treatment and then exposed to light, is probably due to the greater movement into the xylem through undamaged tissue which can occur in the dark. Once the chemical has been absorbed into treated leaves, light-induced damage is required for significant movement through the rest of the plant to take place, but the damage then inhibits further entry of paraquat into the xylem. The movement of paraquat in broad bean and maize is essentially similar, though the enhancement of movement by a period of darkness after application is much less marked.
La migration du paraquat dans les plantes     

THE PHYTOTOXICITY OF SOME HERBICIDES IN FIELD AND POT EXPERIMENTS IN RELATION TO SOIL PROPERTIES

Summary. The phytotoxicities in a number of soils of lenacil, linuron, prometryne and simazine to two indicator plants were determined in field and glasshouse experiments. The results were compared with estimates of the adsorption capacity of the soils obtained by two methods using dimethylaminobenzaldehyde as a model adsorbate. The possible influence of other soil properties was also considered.
One of the adsorption measurements had some predictive value for glasshouse behaviour but was not markedly superior to soil organic carbon content for this purpose. None of the factors studied was usefully correlated with field performance. Results from field experiments in spring were poorly correlated with those from similar experiments in autumn. Neither set of field results related closely to those obtained in the glasshouse. It is concluded that the influence of climate was more important than that of soil type.
La phytotoxiciti de quelquts herbicides dans des experiences en pots et en plein champ, en relation avec les propriétés du sol     

小麦品种对白粉病抗病性与过氧化物酶的关系

 不同抗白粉病小麦品种接种白粉菌后过氧化物酶均呈现两个酶活峰,峰Ⅰ出现在病菌分生孢子梗期,峰Ⅱ出现在分生孢子期。峰Ⅰ的相对酶活性与小麦品种的抗病性呈正相关。SDS-聚丙烯酰胺凝胶电泳扫描的结果显示峰Ⅰ中的高分子量(28,000道尔顿以上)酶带与植株的抗病性有密切关系。高抗品种MN 7213的同工酶谱多一条酶带,可能是抗性基因表达的结果。高感品种VilelaMar.的同工酶谱则在个别酶带上有所加强。     

論柑桔表皮組織对潰瘍病[Xanthomonas citri(Hasse) Dowson]的抵抗性

 利用柑桔不同品种的同样器官或同一品种同一株上不同部位以及不同发育时期的器官,作表皮組織結构的比較观察,証明气孔的形成及发育状态与柑桔潰瘍病的自然侵染(即非伤損侵染)有密切的关系。     

三种幼虫外寄生蜂蛋白酶含量与离体培养饲料的关系

在离体培养幼虫外寄生蜂过程中，发现不同的蜂对饲料中的蛋白质及游离氨基酸的含量有不同的要求，本文对麦蛾茧蜂（Ｂ．ｈｅｂｅｔｏｒ），矛茧蜂（Ｏ．Ｐｌａｌｉａｔｕｓ），管氏肿腿蜂（Ｓ．ｇｕａｎｉ）的蛋白酶活性，饲料中蛋白质及游离氨基酸含量进行了测定．实验表明：蛋白酶含量低的蜂，饲料中含高游离氨基酸及低蛋白；蛋白酶含量高的蜂，饲料中含低游离氨基酸及高蛋白。     

蕃茄根土区系中拮抗性细菌的分布与青枯病发生的关系

对番茄植株根土区系中桔抗菌数量的研究表明，重病田健株根土区系中拮抗菌数量占总分离菌数的比例最大，为８．２％，其中根围拮抗菌的分离频率高于根际与根表，但多数来源于根围的菌株其拮抗作用易丧失，而报表来源的菌株拮抗作用不易丧失。所分离的拮抗菌（９３．２％）属于产芽孢的细菌。     

过氧化物酶及其同工酶与小麦抗赤霉病性的关系

 本文报道了对赤霉病抗性不同的五个小麦品种的过氧化物酶比活力及其同工酶的差异。种子过氧化物酶比活力的大小及其pI10.3酶带颜色的深浅与品种的抗病性呈正相关。各品种的叶片过氧化物酶比活力及其同工酶谱的差异与品种的抗病性无明显相关。各品种的接种穗与其对照穗比较,抗病品种接种穗的过氧化物酶比活力持续上升,感病品种的酶比活力先上升后下降。抗病品种接种穗的过氧化物酶同工酶PI6.3、9.5和10.3三条酶带的颜色比对照深,感病品种的浅或消失,与品种的抗病性呈正相关。     

THE EFFECT OF SOME SEED CHARACTERISTICS ON 2,6-DICHLOROBENZONITRILE TOXICITY

Summary Seeds of thirty-five species of plants were germinated in soil to which varying amounts of 2,6-dichlorobenzonitrile had been added and the doses reducing growth by 50% (GID₅₀) were obtained. An attempt was made to find correlations between growth rates, seed weights and fat contents and the GID₅₀ values. There was no significant correlation with fat contents, but there was a significant correlation of increasing growth rate with increasing susceptibility and a negative correlation of seed size with susceptibility. Seed size was inversely related to growth rate so the extent to which either factor affects the sensitivity of the plants is uncertain. There was no significant difference between the mean sensitivities of monocotyledons and dicotyledons to 2,6-dichlorobenzonitrile.
Effet de quelques caractéristiques de semences sur la toxicité du 2,6-dichlorobenzonitrile     

小麦被白粉菌侵染所致结构、化学变化及其与抗病性的关系

 小麦白粉病菌(Eyrisphe garminis f.sp.tritici)过去一般年份主要在西南地区的云、贵、川等山区发生侵染和危害。     

THE MOVEMENT OF LABELLED 2,4-D IN YOUNG BARLEY PLANTS

Summary. After the 4- or 5-leaf stage in young barley plants, there is a decrease in the translocation of 2,4-D from the leaves to the root system. It is shown that there is no relation between this phenomenon and ear initiation, which occurs at this stage of development. Movement of 2,4-D out of leaves of the tiller in the axils of the 1st and 2nd leaves was also shown to be very small. There is some evidence for a'block'in the movement of 2,4-D in established grass plants.
La migration du 2,4-D marqué dans l'orge     

毛乌素沙区土壤养分含量特征及其生产性能反应——以乌审旗为例

对乌审旗土壤养分测定结果表明,水成土和半水成土(沼泽土、草甸土),有机质含量高,潜在肥力强,速效养分差;地带性土壤(栗钙土)、初育土(黄绵土、风沙土),有机质含量低,但速效养分较高。产生上述现象的原因,决定于环境因素和土壤资源利用的管理水平,特别是水热条件的作用很大。 通过乌审旗土壤养分分析,可以看出毛乌素沙区,土壤养分含量较低。除沼泽土和草甸土有机质含量可作为一级肥力外,分布面积广阔的风沙土,黄绵土,肥力水平均属二级以下,必然影响农作物和牧草的产量。     

毒麦及其变种籽实的成熟结构与内生真菌之间的关系

毒麦的籽实具有毒性,这是早已証实了的。因此,毒麦籽实中菌絲的发現,常被认为与毒性有关。有人肯定其毒性是由于真菌的存在,积存有麻醉性的毒麦碱的緣故。大多数人认为毒麦之有毒,可能与真菌的存在有关,但还不能予以証实。早在1897年曾有人鑑定毒麦籽实中的“有毒真菌”为“Endoconidium temulentum Prill.etDelacr.”;1933年,Günnewig鑑定其菌为“Chaetomium kungeanum Zopf.”;又有人定名为“Stromatinia temulenta Prill.et Del.”。     

CHLORTHAL DEGRADATION IN SOILS AND ITS UPTAKE BY PINE SEEDLINGS

Summary. Similar chlorthal (dimethyl 2,3,.5,6-tetrachloroterephthalate) degradation patterns were found in pot cultures of white pine and Monterey pine grown in a sandy soil and in fallow cultures of the same soil. After 120 days, the content of chlorthal plus its degradation products (as measured by ¹⁴C-activity) had decreased to 37% in the fallow and white pine cultures. A somewhat slower rate of degradation in soil (average 45%*C-activity remaining) was observed for the Monterey pine cultures. Thus in 120 days, 55–63% of the added chlorthal had been lost from the soil system. A negligible amount of this could be accounted for by plant uptake. After 60 days of growth the rate of degradation in soil was greatly curtailed suggesting that the accumulated degradation produces were able to inhibit the further degradation of the herbicide.
Analysis of *C-labelled extracts from the pine tissue showed that uptake of chlorthal varied from 0–25 to 1–2% of the total amount of the chemical added to the soil. Degraded, as well as intact chlorthal, were found in both Monterey and white pine tissue. Very limited mobility of chlorthal in the plant was observed and the concentration in the shoots was less than 10 pm. About 80% of the absorbed chlorthal remained in the root systems. Plant growth led to a rapid dilution of absorbed chlorthal. The growth of both species of pine was rapid and apparently healthy in chlorthal-treated soil and comparable to that of the control plants.     

褐飞虱利它素及其与水稻品种的关系

本文主要研究了稻虱缨小蜂(Anagrus nilaparvatae Pang et Wang)寄主褐飞虱(Nilaparvata lugens(St(?)l))利它素的存在部位、抽提方法以及水稻品种对其蜜露中利它素活性的影响。结果表明:在褐飞虱的各虫态、蜜露及脱皮壳中均存在能引起稻虱缨小蜂触角搜索行为的接触性利它素;干燥蜜露中的利它素活性极显著地低于新鲜和湿润蜜露中的。用二氯甲烷、正己烷、乙醚、甲醇和丙酮均能有效地从褐飞虱若虫和雌成虫中提取利它素。水稻品种能对褐飞虱蜜露中的利它素活性产生明显影响。在测试的6个水稻品种中,取食浙852的褐飞虱蜜露中的利它素活性分别显著和极显著地比取食TN1和Nabeshi的褐飞虱蜜露中的高。     

亚洲玉米螟为害棉花及其卵量与为害数量关系的研究

江苏省棉区亚洲玉米螟1年发生3代,各代均可为害棉花。由于耕作制度的不同,各代在棉田内发生为害程度不一。夏玉米—棉花混作区棉田一代发生量大,二、三代很少为害棉花;春玉米—棉花区主要以二、三代为害棉花;邻近玉米区的稻棉区棉田各代均发生为害,发生轻重与距玉米区远近有关,愈近发生愈重。一代幼虫为害棉花形成的被害数与其卵块在棉田内的密度呈线性关系,而二、三代的为害棉花各受害部位数量与卵块密度呈非线性关系。此外,被害量还与卵块在棉田内的分布有关,在一定的面积上,同样的卵块密度分布集中所引起的为害要轻于分布疏的。     

GROWTH AND SPRAY RETENTION OF WILD OAT AND FLAX IN RELATION TO HERBICIDAL SELECTIVITY*

Summary. The growth of wild oat (Avena fatua L.) was accompanied by an increase in the amount of spray retained per plant and per unit weight of plant, probably because the projected area (plan view) increased as the plant became larger. Flax (Linum usitatissimum L.) retained a fairly constant volume of spray per plant from the 8-leaf to the 35–40-leaf stages, so that the spray retained per unit plant weight decreased considerably as the plants grew. This was related to the decrease in projected area as a proportion of the whole. There was also a difference in retentivity between the cotyledons and true leaves; the cotyledons retained ten to twenty times more spray per unit weight. These results suggest that maximum selectivity would be achieved by spraying at an advanced stage of growth. Wild oat at the 3-leaf stage retained more than half the aqueous spray in the two leaf axils, while flax retained most on the cotyledons. Distribution was shown to be a probable reason for selectivity. Addition of a surfactant greatly increased retention by both species, but although the effect of a spray on wild oat might thereby be increased, under certain conditions injury to flax might be increased and the margin of selectivity reduced. Croissance et retention des bouillies herbicides par la folle-avoine et le lin en rapport avec la sélectivité