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     

EFFECT OF TRANSPIRATION RATE OF BEAN PLANTS ON INHIBITION OF PHOTOSYNTHESIS BY SOME ROOT-APPLIED HERBICIDES

Summary. The inhibition of photosynthesis of bean plants (Phaseolus vulgaris L.) by root-applied herbicides was determined at different rates of transpiration, obtained by varying air humidity, light intensity and temperature. The plants were treated with 5×10^?6M of simazine, simeton, lenacil, isocil, diuron and fenuron in the nutrient solution. CO₂ uptake and transpiration of intact bean plants were measured continuously. The decrease in photosynthesis was more rapid at higher transpiration rates. For each herbicide the total transpiration to the 50% inhibition level of photosynthesis was almost constant at different rates of transpiration, indicating that the degree of inhibition is determined by the transpiration stream in the plants. Treatments with lenacil and diuron resulted in a lower degree of photosynthesis inhibition than did the other herbicides. The results are discussed in relation to uptake studies, herbicidal effects and adsorption phenomena of these and similar herbicides. They are also related to the field performance of such herbicides. Effet de la uitesse de la transpiration des haricots sur l'inhibition de la Photosynthèse par quelques herbicides administerés par les racines Résumé. L'inhibition de la Photosynthèse des haricots (Phaseolus vulgaris L.) par des herbicides administerés par les racines a été déterminèe à des taux différents de transpiration, obtenus en faisant varier l'humidité de I'air, l'intensité de la lumière et la température. Les plantes ont été traitées avec une concentration de 5 × 10^?6 M de simazine, de simétone, de lénacile, d'isocile, de diuron et de fenuron dans la solution nutritive. L'absorption du CO₂ et la transpiration des plantes intactes ont été mesurées en continu. La diminution de la Photosynthèse fut plus rapide pour un taux de transpiration élevé. Pour chaque herbicide, la transpiration totale jusqu'au niveau de 50% d'inhibition dc la Photosynthèse fut assez constante aux différents taux de transpiration, ce qui indique que le degré d'inhibition est déterminé par le courant de la transpiration dans les plantes. Le lénacile et le diuron ont moins influenceé la Photosynthèse que les autres herbicides. Les résultats ont été discutés par rapport à I'assimilation, aux effets phytotoxiques et aux phénomines de l'adsorption de ces herbicides et d'autres produits similaires, Les résultats ont été considerés aussi en relation avec l'effet de ces herbicides au champ. Einfluss der Transpìratìonsìntensität von Bohnen Pflanzen auf die Photosynthesekemmung nach Application einiger Herbizide über die Wurzel Zusammenfassung. Die Photosynthesekemmung von Bohnenpflanzen (Phaseolus vulgaris L.) durch einige üer die Wurzeln applizierte Herbizide wurde unter verschiedenen Transpirationsbedingungen, die durch Änderung der Luftfeuchtigkeit, Lichtintensität und Temperatur erhalten wurden, bestimmt. Die Pflanzen wurden mit 5 × 10^?6 M Simazin, Simeton, Lenacil, Isocil, Diuron und Fenuron in der Nährlösung behandelt. CO₂-Aufnahme und Transpiration intakter Pflanzen wurden kontinuierlich gemessen. Die Abnahme der Photosynthese war bei höherer Transpirationsintensität stärker. Für jedes Herbizid war die Gesamt transpiration bis zur Stufe der 50%-Hemmung bei verschiedenen Transpirationsintensitäten weitgehend konstant. Dieses Verhaiten zeigt, dass der Grad der Hemmung durch den Transpirationsstrom in der Pflanze bestimmt wird. Die Behandlung mit Lenacil und Diuron ergaben einen geringeren Hemmungsgrad als bei den übrigen Herbiziden. Die Ergebnisse werden im Hinblick auf Aufnahme, Herbizidwirkung und Adsorphánosphanomene dieser Herbizide besprochen. Sie werden auch auf die Wirkung dieser Herbizide im Freiland bezogen.     

VERTICAL DISTRIBUTION OF HERBICIDES IN SOIL AND THEIR AVAILABILITY TO PLANTS: TREATMENT OF DIFFERENT PROPORTIONS OF THE TOTAL ROOT SYSTEM

Summary. Uptake of atrazine and linuron by wheat seedlings was measured from different initial distributions of herbicide in the soil. Uptake of both compounds was proportional to the fraction of the total root system exposed to herbicide-treated soil. It was calculated that under the conditions of the experiments, this factor would offset the reduction in concentration of herbicide in the soil following incorporation of 1 kg/ha to 3, 6 or 9 cm, so that after the same time, the concentrations of herbicide in the plants in the different treatments would be similar.
La distribution verticale des herbicides dans le sol et leur disponibilité pour tes plantes: traitement de différentes fractions de l'ensemble du système racinaire total     

三种磺酰脲类除草剂的光解和水解作用

磺酰脲类除草剂属高效除草剂,即用量少,除草活性高。其残留期因药剂而异,据报道,它们的主要降解方式是水解、微生物降解及水溶性光分解作用,在田间土壤含水量与药剂的降解速度成正比。作者研究了氯磺隆(Chlorsulfuron)、氯嘧磺隆(Chlorimuronethyl)、吡嘧磺隆(Pyrarosulfuron-ethyl)3种磺酰脲类除草剂水溶液的水溶性光分解作用和水解作用,对了解该类除草剂的降解作用有重要意义。     

STUDIES ON THE EFFECTS OF HERBICIDES ON SOIL NITRIFICATION*

Summary. A perfusion technique was used to examine effects of selected herbicides (concentration range 50–1000 ppm) on the rate of oxidation of ammonia to nitrate in garden loam soil. Effects on the nitrification rate of soil, previously enriched with nitrifying organisms, were used to estimate direct action on the processes of ammonia oxidation. The kinetics of nitrification in fresh soil were used to estimate effects on bacterial growth and to detect possible adaptations to herbicide toxicity. The herbicides used could be ranged in the following order of increasing effectiveness as inhibitors of ammonia oxidation: dichlobenil < paraquat < picloram < 2,3,6-TBA = chlorthiamid < bromoxynil < chlorflurazole < ioxynil < propanil. Endothal only stimulated ammonia oxidation, even up to 1000 ppm. Endothal, paraquat and 2,3,6-TBA had no apparent effects on bacterial proliferation; the inhibitory effects of the remaining herbicides were in the order: picloram < dichlobenil = bromoxynil < ioxynil < chlorthiamid = chlorflurazole = propanil. With the exception of paraquat and endothal all herbicides seemed to become less toxic during perfusion of fresh soil, i.e. over the enrichment period of 26–28 days. In the case of propanil and chlorthiamid this could have been due to the destruction of the herbicide by soil micro-organisms. With picloram and 2,3,6-TBA it is probable that there was an adaptive loss of sensitivity of the nitrifying organisms to the toxic action of the herbicides. The evidence available suggests that Nitrosomonas is more sensitive than Nitrobacter to herbicide action. Recherches sur les effets des herbicides sur la nitrification Résumé. Une technique de perfusion a été utilisée pour examiner les effets d'une série d'herbicides (á des concentrations de 50 á 1000 ppm) sur le taux d'oxydation de l'ammoniac en nitrate dans un sol de jardin limoneux. Les effets sur le taux de nitrification du sol, préaiablement enrichi avec des organismea nitrifiants, ont été utilisés pour évaluer l'action directe sur les processus d'oxydation de l'ammoniac. Les données cinétiques de la nitrification dans un sol frais ont été utilisées pour évaluer les effets sur la croissance des bactéries et pour déceler les adaptations possible h la toxicité de l'herbicide. Les herbicides utilisés purent être classés comme suit dans i'ordre croissant d'activité inhibitrice de I'oxydation de I'ammoniac: dichlobénil<paraquat<piclorame<2,3,6- TBA = chlorthiamide<bromoxynil<chlorflurazole<ioxynii<propanil. Scul l'endothal provoqua une stimulation de I'oxydation de I'ammoniac jusquà 1000 ppm. L'endothal, le paraquat et le 2,3,6-TBA ne présentèrent pas d'activité apparente sur la proiifération bactérienne; les effets inhibiteurs des autres herbicides furent, dans I'ordrc: piclorame < dichlobenil = bromoxynil<ioxynil<chlorthiamide = chlorflurazole = propanil. A l'exception du paraquat et de l'endothal, tous les herbicides parurent devenir moins toxiques pendant la perfusion sur un sol frais, c'est-à-dire au deli delà période d'enrichissemenl de 26 à 28 jours. Dans le cas du dichlobénil et du chlorthiamide, ceci pourrait avoir été provoqué par la destruction de l'herbicide par lea micro-organismes. Avec le piclorame et le 2,3,6-TBA, il est probable qu'il y eut une adaptation consistanten une perte dela sensibilité des organismes nitrifiants vis-à-vis de i'action toxique des herbicides. Les résultats obtenus suggèrent que les Nitrosomonas sont plus sensibles que les JVitrobacter kà l'action des herbicides. Untersuchungen zum Einfluss von Herbiziden auf die Nitrifikation des Bodens Zusammenfassung. Mit Hilfe einer Perfusionsmethode wurde der Einfluss von bestimmten Herbiziden (Konzentration zwischen 50 und IOO ppm) auf die Oxydationsrate von Ammonium zu Nitrat in Garteniehmboden untersucht. Der Einfluss auf die Nitrifikationsrate des Bodens, der zuvor mit nitrifizierenden Organismen angereichert worden war, wurde als Mass fur die direkte Wirkung der Herbizide auf die Prozesse der Ammoniumoxydation verwendet. Die Kinetik der Nltrifikation in frischem Boden wurde als Mass für die Beeinflussung des Bakterienwaehstums und zur Feststellung einer moglicherweise auftretenden Adaptation an die Herbizidtoxizität verwendet. Für untersuehte Herbizide ergab sich, geordnet nach zunehnnender Hemmung der Ammoniumoxydation, folgende Reihenfolge: Diehlobenil<Paraquat<Pieloram<2,3,6-TBA = Chlorthiamid<Bromoxynil<Chlorflurazole<Ioxynil<Propanil. Endothal stimulierte die Ammoniumoxydation selbst in Konzentration bis zu 1000 ppm. Endothal, Paraquat und 2,3,6-TBA hatten keinen augenscheinlich Efifekt auf die bakterielle Proliferation; fur die Hemmwirkung der ubrigen Herbizide ergab sich folgende Reihenfolge: Picloram < Dichlobenil = Bromoxynil < Ioxynil < Chlorthiamid = Chlorflurazole = Propanil. Mit Ausnahme von Paraquat und Endothal wurden alle Herbizide wahrend der Perfusion dureh frisehen Boden, d.h. wahrend einer Enrichmentperiode von 26–28 Tagen, of Tensichtlich weniger toxiseh. Im Falle von Propanil und Chlorthiamid kann dies auf den Abbau der Herbizide durch die Bodenmikroorganismen zurüekzuführen sein. Bei Piclorani und 2,3,6-TBA handelte es sich wahrscheinlich um einen adaptiven Verlust der Empfindlichkeit der nitrifizierenden Organismen gegenuber der toxisehen Wirkung der Herbizide. Die Ergebnisse lassen den Sehluss zu, dass Nitrosomonas gegenüber Herbizide empfindlicher ist als Nitrobakter.     

二硝基苯胺除草剂对大豆生育影响的研究

作者于1981～1983年所作的系统田间与盆栽试验证明,二硝基苯胺类除草剂中的氟乐灵、二甲戊乐灵对大豆苗期生育有明显抑制作用,表现为:(1)出苗延迟,幼芽下胚轴肿胀、脆弱、矮化,子叶革质状,单位面积用药量对幼芽矮化的影响比混土深浅大;(2)侧根显著受抑制,这种抑制作用局限于药土层,混土深度对大豆侧根的抑制比用药量高低的影响更显著;(3)根瘤菌形成受抑制,根瘤数减少,叶面积减小。随着大豆生长,上述抑制作用逐步消失,对大豆产量无显著影响。在供试3种除草剂中,丁乐灵对大豆生育无影响。从安全、经济、高效考虑,氟乐灵与二甲戊乐灵的适宜用量为1.0公斤,丁乐灵为1.5公斤/公顷,将药剂施于大豆种子之上的土层为宜,亦即施药后耙地不宜过深,将药剂混拌于0～6厘米土层为佳。     

水稻类普矮病的研究Ⅰ.类普矮病——水稻上的一种新的病毒病

 水稻类普矮病在闽西、闽北和闽南均有发生,其为害性不可忽视。病害症状因品种不同而表现为两种基本类型——普矮型和草丛型。将类普矮病和普矮病接种在同一稻苗上.可先后产生各自的症状。
病害仅能通过黑尾叶蝉和二点黑尾叶蝉传播。电光叶蝉、白翅叶蝉、褐飞虱和缢管蚜均不传病。     

花卉杂色花的研究

 在云南昆明、玉溪、楚雄、曲靖等地区,我们发现四种花卉有杂色花。所谓杂色花是由病毒侵染而引起的一种特殊花,它鲜艳美丽比无病的花还好看。这种花早在十六世纪于荷兰种植的郁金香上发现,即在花瓣上产生一种白色花斑或条纹,比一般的单色花更加美丽,于是身价倍增,当时人们互相争购,因此把此时期称为"郁金香疯狂时代(Tulipomania)",后来经病毒接种试验证明是由郁金香碎色病毒(TBV)引起的。     

THE FATE OF PARAQUAT APPLIED TO PLANTS

Summary. Paraquat dichloride was applied to maize, tomato and broad bean plants as droplets of an aqueous solution and analysed al intervals. It was shown to be degraded under some conditions, but the amount of degradation was least under conditions which would have been most favourable for metabolism of the chemical. The analytical results and results from cation-exchange paper chromatography and thin layer chromatography showed that the degradation was caused by photochemical decomposition on the surface of the leaves of the plants, not by metabolism. The degradation was not observed in the dark, and only occurred to a significant extent in daylight in the summer.
Two photochemical degradation products from methyl-labelled paraquat-¹⁴C dichloride, viz., 4-carboxy-l-(methyl-¹⁴C)-pyridinium chloride and methylamine-¹⁴C hydrochloride, were isolated from plants sprayed with the herbicide.
Le devenir du paraquat dans les plantes traitées     

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。     

VERTICAL DISTRIBUTION OF HERBICIDES IN SOIL AND THEIR AVAILABILITY TO PLANTS: SHOOT COMPARED WITH ROOT UPTAKE

Summary. Turnip, lettuce and ryegrass seedlings showed toxicity symptoms following shoot exposure to atrazine, linuron and aziprotryne at soil concentrations less than would be obtained from normal field applications. Responses following shoot exposure to simazine and lenacil were much less. Root exposure to all five herbicides caused seedling death at concentrations lower than those required for 'shoot-zone' toxicity. Pronamide and chlorpropham were tested against ryegrass only and at the concentrations examined were toxic only when localized in the shoot zone. Root exposure suppressed root growth, but the shoots were able to grow normally if the soil was kept sufficiently moist. Shoots contained more ¹⁴C-atrazine at emergence after shoot exposure compared with root exposure, but there was little subsequent uptake from the shoot zone. There was extensive uptake from the root zone after emergence. In the shoot-zone treatments, concentrations in the plant were high at emergence but were rapidly diluted by plant growth, whereas with root exposure, they increased throughout the experiments. The possible significance of these results to herbicide bebaviour under field conditions is discussed.
La distribution verticale des herbicides dans le sol et leur disponibilité pour les plantes: absorption comparée par la partie aèrienne et par les radnes     

THE RESPONSE OF TOBACCO TO SEEDBED APPLICATION OF DIPHENAMID

Summary. Seeds of three tobacco Nicotiana tabacum L.) varieties were soaked in water for 0, 1, 3 or 5 days and treated, after sowing in glasshouse flats, with NN -dimethyl-αα-diphenylacetamide (diphenamid) at 4·5 kg/ha 1, 3 or 5 days after sowing or at the cotyledonary stage. Unsprayed series were included as controls. Diphenamid caused thinning of seedlings in all varieties, but one (Maryland Catterton) showed some tolerance. All varieties showed stunting and malformations from diphenamid, particularly when seeds soaked for 5 days were treated either 1 or 5 days after sowing.     

THE DEVELOPMENT OF HERBICIDES FOR POTATOES

Summary. Since 1961 the Weed Research Organization has been testing and developing herbicides for weed control in potatoes. Inthe three experiments which are reported, herbicides were compared with other forms of weed control. The first experimentin 1961 was exploratory and compared yields following hand-weeding versus no weed control versus several promising herbicides. The highest yield was produced by the hand-weeded crop. Several herbicide treatments applied before crop emergence gave useful selective weed control.
Assuming weed control to be necessary, selected herbicides were then compared in 1962 and 1963 with conventional mechanical cultivations. In both years successful weed control by herbicide resulted in a higher yield of potatoes than did mechanical cultivation although the soil-acting chemical used in 1962 caused some crop damage. The 1963 experiment included triangular planting patterns, at normal and high plant densities. Increases both in gross and marketable yield were obtained at normal plant density with the triangular arrangement as compared with the row crop. The high plant population resulted in the largest gross yield but a lower yield per plant and smaller average tuber size.     

青海高原农田野燕麦发生特点及除草剂应用技术的初步探讨

本文对青海高原农田野燕麦的发生特点,如出苗、生长发育、繁殖和传播、种籽抗逆性等进行了初步试验。为认识野燕麦的危害性和制定防除措施提供了依据。在化学除草方面,试验了十几种除草剂和不同的应用条件,初步认为“深埋药”、“狠抓水”、“防耗损”、“促生长”是保证药效的重要环节。对旱地除草剂的应用有一定参考意义。     

QTL作图在植物数量抗病性遗传研究中的应用

 本文综述了近年来在植物数量抗病性遗传研究方面的进展及发展动态。列举了利用DNA分子标记定位和估计植物数量抗性座位或基因(QRL)的18个实例,从中归纳总结了控制植物数量抗病性的QRL数目、类别、效应及其基因与基因和基因与环境、植株生育期、病菌生理小种(或致病类型)间的互作关系。展望了QTL作图对复杂的数量抗病性的标记辅助选育和数量抗性基因图位克隆的发展前景。     

RESPONSE OF YELLOW NUTSEDGE,FLORIDA PUSLEY,AND PEANUTS TO THIOCARBAMATE HERBICIDES AS AFFECTED BY METHOD OF PLACEMENT IN SOIL*

Summary. Thiocarbamate herbicides were applied with incorporation devices and new subsurface application equipment on loamy sand at Tifton, Georgia, U.S.A. Subsurface-applied ethyl N,N-dipropylthiolcarbamate (EPTC), S-propyl bulylethylthiocarbamate (pebulate), and S-propyl dipropylthiocarbamate (vernolate) generally gave better control of Cyperus esculentus L. and Richardia scabra St Hil, but injured peanuts more than applications made on the soil surface and then incorporated into the soil. For soil incorporation, the power-driven rotary hoe was generally better than a disc harrow. Depth of subsurface placement critically affected herbicidal activity, especially on Cyperus esculentus; placement 1·5 in. below the soil surface gave more effective control than placement at 5·5 in. Réactions de Cyperus esculentus, de Richardia scabra et de l'arachide mix herbicides à base de thiocarbamate, en relation avec la methode de placement dans le sol     

THE RESPONSE TO VARIATIONS IN NITROGEN LEVEL OF SOME WEED SPECIES OF THE SUDAN

Summary. Five weed species, Argemone mexicana, Calotropis procera, Cynodon dactylon, Cyperus rotundus and Dactylocleniwn aegyptium , and two crop plants, Gossypium barbadense and Sorghum vulgare , were grown at five nitrogen levels (3, 9, 27, 81 and 243 ppm N) in sand-culture. The response of the species was noted in terms of total dry-weight yield, percentage dry-weight and mm; shout ratio.
Cynodon dactylon and Calotropis procera both showed a strong linear relationship between dry-weight yield and nitrogen level, yield increasing with increase in nitrogen concentration. This response was at a higher overall level and higher rate in the former species. Argemone mexicana , and the two crop plants, yielded best at 81 ppm, yield being depressed by the highest nitrogen level. Dactyloctenium aegyptium showed a somewhat similar response to Argemone mexicana . Cyperus rotundus exhibited yield peaks at 9 and 81 ppm N. Percentage dry-weight values were highly variable but in most cases highest yield was accompanied by the highest shoot : root ratio.
The responses of the species are discussed in relation to the soil factors prevailing in the habitats in which they are usually found. Adaptation on the part of some weed species is suggested where the yield response is similar to that of some of the crop plants with which they are usually associated.
The ability to reproduce similar reactions to variations in nitrogen level on the part of three weed species, on two separate occasions, indicates that real and reliable responses can be demonstrated in work of this kind.
Réaction de quelques espèces de mauvaises herbes du Soudan à diverses concentrations d'azote     

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。