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     

AVAILABILITY TO PLANTS OF PARAQUAT ADSORBED ON SOIL OR SPRAYED ON VEGETATION*

Summary. Paraquat adsorbed on peat soils was available to plants in amounts as low as l/25th of their Strong Adsorption Capacity (SAG). In Begbroke soil the paraquat was available to plants only near the SAG. Paraquat sprayed at usual doses on the surface of peat soils and not incorporated reduced growth of seedlings of Lolium perenne L. placed on the surface. Seeds sown 6 mm below a sprayed surface were only affected in one soil at a high rate of application. Hypocotyl uptake of adsorbed paraquat took place only with applications of more than 82 kg/ha in a peat soil and 230 kg/ha in Begbroke soil. Paraquat on litter of sprayed plants was found to be available to plants through root uptake. Living leaves can also adsorb paraquat from sprayed leaves if they are in contact. Disponibilité our les plantes du paraquat adsorbé sur le sol ou appliqué sur la végitation Résumé. Le paraquat adsorbé sur des sols tourbeux fut disponible pour les plantes en quantités n'atteignant que 1/25 de leur capacité brute d'adsorption (GBA). Dans le sol de Begbroke, le paraquat ne fut disponible pour les plantes qu'au voisinage de la CBA. Le paraquat appliqué aux doses usuelles à la surface de sols toturbeux, et non incorporé, réduisit la croissance des plantules de ray-grass placées sur cette surface. Les semences semées á 6 mm de profondeur sous une surface traitée furent affectées dans un sol seulement et á une dose d'application élevée. L'absorption par I'hypocotyle de paraquat adsorbé se produisit seulement avec des applications à des doses supéieures à 82 kg/ha dans un sol tourbeux et 230 kg/ha dans un sol de Begbroke. Le paraquat sur une litiére de plantes traitées se montra disponible pour les plantes par absorption racinaire. Les feuilles vivantes peuvent aussi adsorber le paraquat de feuilles traitées si elles sont en contact avec elles. Pflanzenverfugbarkeit von im Boden adsorbiertem oder auf PJlanzen gespritztem Paraquat Zusammenfassung. Im Moorboden adsorbiertes Paraquat war fur Pflanzen verfügbar in Mengen um 1/25 der Kapazität zur festen Adsorption (Strong Adsorption Capacity, SAG). In Begbroke-Böden war Paraquat für Pflanzen nur ungefähr in der Höhe des SAG verfügbar. In normalen Aufwandmengen atif die Oberfläche von Moorboden gespritztes und nicht eingearbeitetes Paraquat verminderte das Wachstum von Keimpflanzen von atif der Oberfläche ausgesätem Lolium perenne L. Scchs Millimeter unterhalb der Ober-flache eingesáte Samen wurden nur in einem Boden bei hoher Herbizidkonzentration beeinflusst. Hypocotyle Aufnahme von adsorbiertem Paraquat erfolgte nur bei Aufwandmengen von mehr als 82 kg/ha in Moorböden und 230 kg/ha in Begbroke-Boden. Paraquat an Rückständen von behandelten Pflanzen war durch Wurzelaufnahmc für andere Pflanzen verfügbar. Ausserdem können lebende Blatter Paraquat von behandelten Blättern adsorbieren, sofern sie in Kontakt mit dicaen stehen.     

COMPARISION OF RATES OF PARAQUAT PRIOR TO DIRECT-DRILLING CEREALS

Summary. Trials were conducted in East Anglia to compare direct-drilling following paraquat at 1 and 2 lb/ac with normal cultivations for both winter wheat and spring barley. The three treatments were compared at two levels of nitrogen.
With direct-drilled winter wheat, yields were higher after using paraquat at 2 lb/ac and at this rate there was little difference between direct-drilling and normal cultivations when 100 units of nitrogen were applied in spring. When only 50 units were given the results were more variable, with direct-drilling significantly outyielding normal cultivations in one trial, being outyielded in another and showing no difference in the third.
Yields of spring barley were slightly higher after paraquat at 2 lb/ac as compared with 1 lb/ac, but not significantly so. The time of application of paraquat influenced yield; when applied in December yields from direct-drilling and normal cultivations were similar, but when applied in February higher yields were recorded with normal cultivations.
Comparaison des doses de paraquat a utiliser avant un semis direct de dreales     

THE TOXICITY OF PARAQUAT TO A RANGE OF SPECIES FOLLOWING UPTAKE BY THE ROOTS*

Summary. The sensitivity of eight species to paraquat taken up through the roots was tested in nutrient solution experiments. Ryegrass, lettuce and carrot, which were found to be the most sensitive, were assessed for response to paraquat in a peat soil. Lettuce and ryegrass were the most suitable of the eight species for soil bioassays. Toxicité du paraquat pour diverses espéces aprés absorption par les racines Résumé. La sensibilité de huit espéces au paraquat absorbé par les racines a étéétudiée dans des experiences en solutions nutritives. Le ray-grass, la laitue et la carotte qui se sont montrés les plus sensibles furent employés pour évaluer la réaction au paraquat dans un sol tourbeux. La laitue et le ray-grass furent, parmi les huit espéces, les plus appropriate aux essais biologiques. Phytotoxizitdt von Paraquat gegeniiber einer Anzahl von Arten nach Wurzelaufnahme Zusammenfassung. Die Empfindlichkeit von acht Arten gegenuber Paraquat nach Wurzel Aufnahme wurde in Wasserkulturversuchen untersucht. Weidelgras, Salat und Möhren hat ten sich als am empfindlichsten erwiesen und wurden auf ihre Reaktion gegenuber Paraquat in einem Lehmboden untersucht. Salat und Weidelgras erwiesen sich von den acht untersuchten Arten als die beiden geeigneuten für Bodenbiotests.     

STUDIES OF THE RESPONSE OF PLANTS TO ROOT-APPLIED HERBICIDES

Summary. Peas, barley and linseed were grown in water-cuture. Roots were divided into two portions and contained in separate vessels. The effect of herbicides applied to one-third of the roots was compared with their effect when applied to the whole root system.
Propham, chlorpropham, atratone and 2,3,6-TBA killed the plant whether application was to one-third or all of the roots. Roots in direct contact with propham, chlorpropham and 2,3,6-TBA were deformed or killed, while roots in uncontaminated solution remained healthy. The effect of atratone and high concentrations of chlorpropham on a portion of the roots was transmitted to roots not in the toxic solution.
Certain concentrations of MCPA and DNOC applied to the whole root system killed the plant while three times the concentration to one-third of the roots caused local damage but had little effect on the plant as a whole. Sufficient herbicide may be taken up by one- third of the roots from high concentrations to kill the whole plant.
TGA gave variable results with respect to the health of the aerial portion of the plant but had no obvious direct effect on root growth.
Propham, chlorpropham, atratone and 2,3,6-TBA reduced transpiration rates whether applied to part or whole root systems. MCPA and DNOC prevented water uptake by roots with which they Were in direct contact.
Etudes sur les réactions de certaines plantes à des herbicides appliqués aux racines I. Effet d'une application localisée     

STUDIES OF THE RESPONSE OF PLANTS TO ROOT-APPLIED HERBICIDES

Summary. Applications of several herbicides -were made to roots and to the bases of shoots of peas, cucumber, mustard and barley grown in soil, sand or water culture.
Localized applications (variation horizontal) of atratone and MCPA to roots of peas and barley in soil produced effects similar to those observed in water euluire, described in Pan I. Airatone killed the plants whether available to the whole or to only a portion of the root system whereas MCPA affected only the roots with which it was in direct contact, and growth continued when a portion of the root system was in herbicide-free environment.
In water culture, MCPA was more effective when applied to the lower (younger) roots with the upper (older) roots kept dry than when twice the concentration was applied evenly to the whole root system in water. When all the roots were kept wet the effect of application to the upper roots was greater than the effect of application to the lower roots. The response of plants to atratone was not appreciably altered whether applications were made to the upper or lower parts of the root system in water culture. Variations in water level had little effect.
Even when the herbicide solution was confined to the stem or hypocotyl, atratone and DNOC were little, if any, less effective than when applied to roots. MCPA, both as ester and sodium salt, was significantly less effective.
Partial replacement of solution in the root zone by sand and air did not reduce the activity of atratone at a given concentration. Similar replacement in the zone of the stem or hypocotyl greatly reduced the effectiveness of all herbicides. When sand of low water content was used, atratone and MCPA-sodium became quite ineffective via the stem, but DNOC and MCPA-ethyl ester remained active.
Études sur les réactions de certaines plantes á des herbicides appliqués aux racines II. Observations nouvelles sur l'effet de l'application localisée.     

FACTORS AFFECTING THE PHYTOTOXICITY OF PARAQUAT*

Summary. Temperatures of 5–6° C delayed leaf necrosis of glasshouse-grown oats (Avena sativa), winter peas (Pisum sativum), huisache (Acacia farnesiana), mesquite (Prosopis julijiora var. glandutosa), live oak (Quercus virginiana) and yaupon (Ilex vomitoria) for at least 48 hr after treatment with paraquat as compared with higher temperatures. After 96 hr, oats, winter peas, huisache and mesquite at 5° C usually showed as much necrosis as plants at 24–28° C. Similar results were obtained with live oak and yaupon, and with yaupon in the field, except that longer periods were sometimes required for plants at low temperatures to develop injury comparable with that at higher temperatures. Washing yaupon and live oak leaves 1 hr after application reduced the effectiveness of paraquat regardless of temperature, but washing winter peas 10 min after application had little or no effect on phytotoxicity. Field-grown mesquite showed extensive leaf necrosis when leaves were washed after 20 min, live oak leaves similarly treated and washed were not injured, while the response of winged elm (Ulmus alata) was intermediate. Percentage leaf necrosis of mesquite, winged elm, yaupon and live oak increased with increasing paraquat concentration; 6–9 μg/leaf on mesquite and 20 μg/leaf on winged elm gave 100% necrosis after 4 days. Complete leaf necrosis of live oak and yaupon was not attained during this period even with 80 μg/Ieaf. Nursery-grown mesquite, yaupon and greenbriar (Smilax bona-nox) and natural stands of yaupon were treated at two growth stages, in March and May. Paraquat was more effective on mesquite when applied in May, but there were no differences with the other species. Facteurs affectant la toxicité du paraquat     

抗TSWV转基因烟草植株的初步研究

 番茄斑萎病毒(Tomato spotted wilt virus,即TSWV)是一种寄生范围很广、世界性分布的植物病毒,能对多种作物(包括烟草)造成严重的危害。该项研究,是把TSWV的外壳蛋白基因转入烟草,获得了抗TSWV的转基因烟株,进一步检验其对TMV的抗性并检测其后代植株中的目的基因。     

转抗虫基因烟草植株对棉铃虫幼虫抗性能力的研究

作者等对转CpTI基因烟草植株进行了抗棉铃虫能力的评估。用死亡率、蜕皮指数、平均体重、生物总量和植株受害程度等5个指标,综合判断转基因植株的抗性水平。结果表明,检测的10株转基因植株中对棉铃虫表现为高抗、中抗的各占4株,低抗的占2株。高抗植株测试虫校正死亡率达90％以上,中抗植株测试虫校正死亡率达75％以上,差异显著,在高抗植株上生长的测试虫蜕皮指数低于标准的30％,总虫重仅为对照的1％,中抗植株上生长的测试虫蜕皮指数是标准的30％～40％,总虫重为对照的3％～7％。综合分析结果表明,高、中抗植株对棉铃虫的抗性明显。     

THE INFLUENCE OF SIZE OF SPRAY DROPLETS ON THE HERBICIDAL ACTIVITY OF DIQUAT AND PARAQUAT

Summary. Single droplets ranging in size from 250 to 1000 μ diameter and concentrations of diquat and paraquat over the range 0–09–0.75% ion were examined for herbicidal activity. Size of droplet and concentration of herbicide in the droplet were shown to have a marked influence on activity. An increase in droplet size above 250 μ increased herbicidal efficiency. An optimum was reached between 400 and 500 μ while activity fell off with a further increase to 1000 μ.     

稻瘟病抗性自然诱发鉴定及其效果的探讨

 本文对如何进行抗瘟育种,尤其对如何进行稻瘟病自然诱发鉴定提出了一些见解和建议,如不主张重氮施肥,不主张长期灌水等,对指导今后工作有一定值价。     

THE REACTION OF WHEAT TO 2,4-D ETHYL ESTER APPLIED IN DIFFERENT DILUENTS

Summary. In experiments at two sites in Western Australia, 2,4-D ethyl ester was applied to Gabo wheat at the early tillering, advanced tillering and boot stages. A standard dose of 6 oz/ac a.e. was sprayed in diesel oil (4 pints/ac), water (4 pints/ac) and water (8 gal/ac), and half of each plot received a double application, to give twice the dose and twice the volume. The weed populations were negligible and differences obtained were attributable to the direct effects of the treatments on the wheat.
The most satisfactory treatment was 6 oz/ac applied in 8 gal/ac water at the early tillering stage. Contrary to previous evidence, application at the advanced tillering stage resulted in yield reduction, and it is supposed that the reaction of the wheat was affected by insufficient soil moisture during the later stages of growth. Application in 4 pints/ac water gave lower yields than application in 8 gal/ac, while with 4 pints/ac oil, yields were rather less than with 4 pints/ac water. Although there were some statistically significant effects on the germination and unit weight of the grain, these were not considered to be of practical importance.
Réaction du bléà l'ester éthylique du 2,4-D appliqué dans divers diluants     

棉株体内几种生化物质与抗枯萎病之间关系的初步研究

 棉花抗枯萎病品种86-1、陕1155,感病品种岱15、徐州142。在棉幼苗三叶期用采自河南王屯的棉枯萎菌7号小种接种,接种后12小时,各抗病品种的葡萄糖、核糖含量显著增加,而感病品种则相反。接种后抗病品种的苯丙氨酸解氨酶(PAL)活性峰出现早于感病品种,相对酶活值也高于感病品种。接种后抗病品种蛋白质含量出现先低后高趋势,感病品种则始终保持较高水平。木质素含量的增加与棉花品种抗病性存在正相关性。伴随着PAL活性的增加,木质素含量也迅速增加。结果表明,棉花品种对枯萎病的抗性与PAL活性有密切关系,并通过代谢最终产物之一的木质素的增加得到表达。     

地产蛭石在干旱地区直接施用的研究

本试验利用地产混合蛭石直接施入土壤,观察蛭石的不同用量对土壤主要物理性状,土壤持水力、土壤水分常数,根区速效养分,作物生理功能及产量等综合影响的结果表明:每放施用地产混合蛭石240kg,120kg与对照比较,不仅分别增产15.5%、13.43%,而且还可改善种子品质。     

DIRECT-DRILLING OF CEREALS AFTER USE OF PARAQUAT

Summary. Cereal crops were grown at Jealott's Hill in 1962 and 1963 without cultivations, following the use, before drilling, of paraquat to kill unwanted vegetation. This investigation was extended with a series of trials at outside centres. Three trials with winter wheat were drilled in the autumn of 1963, two into pasture and one into stubble. Three barley trials were drilled into stubble in spring 1964.
All the autumn trials and one spring trial compared direct-drilling with normal cultivations at two levels of nitrogen. The other two spring trials compared rates and times of application of paraquat without any plough comparison.
Individual trials showed significant yield differences between direct-drilling and ploughing, but there was no consistent advantage in favour of either technique.
Spraying in advance of drilling generally resulted in similar yields to spraying and drilling on the same day. Winter wheat drilled into pastures showed some retardation of spring growth when spraying and drilling had been carried out on the same day.
When averaged over times of application, yields after spraying paraquat at 2 lb/ac were significantly higher than after 1 lb/ac.
In the trials where two levels of nitrogen were included crops responded to an increase from 60 to 120 units nitrogen/ac as top dressing for winter wheat and from 60 to 90 units nitrogen/ac combine-drilled for spring barley; the response was not always significant.
Semis direct de céréales après application de paraquat     

四个小麦品种的慢白粉病抗性研究

 小麦品种里勃留拉、咸农4号和阿勃为慢白粉病品种,它们的AUDPC、单菌落面积、单菌落日产孢量和最终病情指数,都显著低于对照品种山前;小偃6号属中慢品种,它的最终病情指数和AUDPC与对照间的差异,分别为极显著和显著。用8个白粉菌小种接种表明,这4个抗病品种属非专化抗性。试验和分析表明,只需在倒2叶上测定最终病情指数和菌落大小,即可鉴定小麦品种的慢白粉病抗性。     

四个小麦品种的慢白粉病抗性研究

小麦品种里勃留拉、咸农4号和阿勃为慢白粉病品种,它们的AUDPC、单菌落面积、单菌落日产孢量和最终病情指数,都显著低于对照品种山前;小偃6号属中慢品种,它的最终病情指数和AUDPC与对照间的差异,分别为极显著和显著。用8个白粉菌小种接种表明,这4个抗病品种属非专化抗性。试验和分析表明,只需在倒2叶上测定最终病情指数和菌落大小,即可鉴定小麦品种的慢白粉病抗性。     

棉花对棉铃虫为害的补偿能力及防治策略的探讨

1983—1986年在河北邯郸通过不同处理(虫量、土壤肥力、品种)的田间试验分析,系统研究了棉花对于棉铃虫为害的补偿能力及其影响因素,并在此基础上提出了华北棉区棉铃虫防治新策略的建议。     

转基因抗病毒工程烟草的田间抗性试验

方荣祥等将烟草花叶病毒(TMV)和黄瓜花叶病毒(CMV)的外壳蛋白(CP)基因转入我国烟草主栽品种NC89后,经过连续两年3代的田间选择鉴定,于1990年秋在河南获得了几个纯合的转基因抗花叶病烟草株系（待发表）。