摘要:

Summary.Seedlings of Galinsoga parviflora and Polygonum convolvulus were cultured in nutrient solution and soil with C‐1983‐14C. Uptake and translocation of herbicide was followed by measuring radioactivity in roots, stems and leaves as a function of time. The capacity of the two plants to take up C‐1983 from nutrient solution and to translocate it into stems and leaves was found to be strikingly different. The difference in herbicidal effect of C‐1983 on the two species parallels the concentration of radioactivity translocated into leaves. Uptake of C‐1983 from nutrient solution as well as subsequent translocation to top parts by lowering temperature increasing humidity and transfering the plants from light to darkness.In soil cultures, the two plants were found to take up and to translocate smaller quantities of C‐1983 than was to be expected from the calculated soil solution concentration.The mechanisms regulating the rate of uptake C‐1983 from nutrient cultures and soils are discussed. The strong adsorption of C‐1983 in tissues appears to be a decisive factor in controlling movement of the herbicide in plants.Le comportement de la N'‐(4‐chlorophenoxy)‐phenyl‐NN‐dimethyluric (C‐1983) dans les terres et dans les plantes II. Absorption e

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00235.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

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 ap

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00236.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00237.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.The variation in the percentage of dormant corms ofHomeria breynianabetween sites and years was shown for a 3‐year period. The highest dormancy count of 61 % was obtained at Wagin in 1959 while the lowest count of 1% was also obtained in 1959 at Muchea. It was demonstrated that soil surface cover plays an important part in corm dormancy. In 1961 the removal of the surface cover by burning almost eliminated dormancy. Removing the cover at three dates during the summer did not affect the germination of corms during the late autumn. Moreover, corms left in the soil throughout the summer exhibited no physiological dormancy in April. In laboratory tests the percentage germination steadily decreased as the test temperatures were reduced from 25 to 5° C. Soil temperatures follow a similar decline in Western Australia during April and May. Light rains of 12 and 14 points (100 points = 1 in.) gave a significant increase in soil moisture where the surface was bare. Sufficient moisture penetrated to cause a general germination of corms and this resulted inH. breynianaemerging on bare soil some 3 weeks earlier than where surface cover was present. The diurnal temperature range at this time was 54–68° F. The break of the season (the beginning of the growing season) did not occur until 17 days later, and the diurnal soil temperature range had dropped to 49–54° F. Corms subjected to germination tests at these two temperature ranges gave a 90% and 70% sprouting respectively.La dormance des bulbes deHomeria breyniana

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00238.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.Five weed species,Argemone mexicana, Calotropis procera, Cynodon dactylon, Cyperus rotundusandDactylocleniwn aegyptium, and two crop plants,Gossypium barbadenseandSorghum 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 dactylonandCalotropis proceraboth 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 aegyptiumshowed a somewhat similar response toArgemone mexicana.Cyperus rotundusexhibited 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 concentra

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00239.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.The effect of sub‐lethal doses of MCPA‐sodium and 2,3,6‐TBA‐sodium on young cucumber plants was studied in three replicated experiments. The materials were applied either to the leaves of plants in pots or as a soil drench. Epinastic and formative effects were observed. Formative effects included leaf inrolling and blistering, stem and petiole proliferation, and root modification. The symptom pattern resulting from application of each material was described.Les effets du MCPA et du 2,3,6‐TBA sur Us concombres cultiv

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00240.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.Large‐scale field testing of herbicides nccessitales the use of small experimental plots. Most of the available small‐plot experimental sprayers do not have any mechanical control of the speed of the spray boom and thus depend on the speed of the operator or an pushed by or mounted on various types of vehicles. Inability to attain a desired speed of the spray boom over a short distance by mechanical means has hindered the development of a precise small‐plot sprayer. This problem was resolved by the attainment of the desired speeds prior to the release of the spray boom. The principal parts of the unit are: (1) speed control and drive mechanism with an endless cable running at speeds of 1, 2 and 3 miles/hour; (2) boom‐carrier which may be locked to the continuously running cable; (3) rotary gear pump; (4) pressure regulator; and (5) spray boom with two ‘even spray Teejet’ nozzles. The entire machine is 6 ft wide and 13 ft in length and sprays a plot 5 ft wide and 10 ft long. The unit is mounted on four wheels for transport from plot to plot. During its initial trials in the field, the unit has shown precision, accuracy and repeatability in small‐plot spraying, seldom attained by small‐plot sprayers. In addition the unit is simple in design and can be easily assembled by an experienced mechanic.Un pulverisateur de précision pour petites parcell

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00241.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00242.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00243.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1963.tb00244.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY