摘要:

Summary:E. crassopes requires specific conditions for germination. The best laboratory germination was in clay soil, rich in organic matter, under less than 3 cm depth of water, in light. There are interactions with water depths, soil type, organic deposits, light and temperature.Storage conditions of seeds before germination affect the results. Wetting, drying and re‐wetting gave quickest, and complete germination. After 2 years dry‐storage, 78% of the seeds were still via

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00383.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Summary:Plants of Ulex europaeus were grown from cuttings and studies made of the absorption of 14C‐picloram applied with unlabelled 2,4,5‐T. In vivo experiments in a growth chamber showed that absorption ceased after 10 h, but was resumed on wetting. In in vitro experiments the Q10 and the activation energy for uptake decreased with increasing temperature. Absorption was increased by addition of non‐ionic surfactants, by lowering the pH and by removal of cuticular wax. Gorse shoots were shown to have a high wax content but scanning electron microscopy revealed no obvious wax structures and the contact angle of spray droplets was less than 900, indicating that the surfaces were not difficult t

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00384.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Summary:Quantitative determinations of chlorophyll showed thatCuscuta hyalina and Striga hermonthica possesschlorophyll. No trace of chlorophyll was found in Orobanche ramosa. Autoradiographic evidence showed that both radiocarbon and radiophosphorous moved from host to parasite in alt three species. Photosynthesis occurs in S. hermonthica when the parasite is isolated from its host. The adventitious roots of S. hermonthica and O. ramosa appear to be functional in absorbing a proportion of the required inorganic substances and water. S. hermonthica is a hemiparasite,O. ramosais a holoparasite butC. hyalinais best described as a partial parasite.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00385.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Zusammenfassung:Das Herbizid 2‐Chlor‐3‐(4‐chlorphenyl)propionsauremethylester (Chlorphenprop‐methyl) wurde in Sand‐und Lehmboden bei 21°C innerhalb weniger Stunden hydrolysiert. Das Hydrolyseprodukt 2‐Chlor‐3‐(4‐chlorphenyl)propionsäure (CPP) wurde in beiden Böden bei 22.0 ppm Anfangskonzentration mit einer Halbwertszeit von 4 bis 8 Tagen. bei 4.4 ppm Anfangskonzenlralion mit einer Halbwertszeit von knapp einem Tag abgebaut. Als Zwischenprodukt des CPP‐Abbaus in Boden wurde 4‐Chlorbenzoesaure, in Mischkulturen von Bodenmikroorganismen ausserdem 4‐Chlorzimtsäure identifiziert. Tn autoklaviertem und mit NaN3sterilisiertem Boden unterblieb der Abbau von CPP. Die Anreicherung und Isolierung von Mikroorganismen, die den ersten Schritt des CPP‐Abbaus vollziehen, war nicht möglich. Zwei aus den VersuchsbÖden isolierte und vorläufig den GattungenFlavobacterium bzw. Brevibacteriumzugeordnete Bakterienstämme bauten den Metaboliten 4‐Chlorzimtsäure zu 4‐ Chlorbenzoesäure ab, zwei de r Gattung Arthrobacter Zugeordnete Bakterienstämme wuchsen auf der 4‐Chlorbenzoesäure als alleiniger Kohlenstoffquelle. Die Ergebnisse sprechen insgesaml dafär, dass Chlorphenprop‐methyl im Boden zunächst zu CPP hydrolysiert wird, welches anschliessend über 4‐Chlorzimtsäure zu 4‐Chlorbenzoesäure abgebaut wird. Von der 4‐Chlorbenz

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00386.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Résumé:On a éludié l'adsorption et la désorption de la pyrazone sur des colloïdes organiques et minéraux et sur des résines échangeuses d'ions saturées par les ions H+, Na+, K+, Ca++et Mg++. Pour ce qui concerne les adsorbants‐H, on a trouvé l'ordre d'adsorption suivant: Amberlite‐H>Dowex‐H>humus‐H>montmorillonite‐Al,H>illite‐Al,H>kaolinite‐ Al,H. Cette adsorption, qui semble etre due à des liaisons physiques et non à des mécanismes de protonation, est plus grande que celle trouvée avec des systèmes‐K, ‐Na, ‐Ca, et ‐Mg. Avec des systèmes‐Ca on a obtenu le même ordre d'adsorption: Dowex‐Ca>montmorillonite‐Ca>illite‐ Ca>kaolinite‐Ca. Contrairement à ce que nous avons trouvé pour la résine Dowex, avec la montmorillonite et l'illite, le cation saturant semble avoir un effet sur l'adsorption de la pyrazone; en effet nous avons obtenu l'ordre suivant: Ca++>Mg++>K+>Na+. Pour tons les systèmes que nous avons examinés

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00387.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Summary:The extent to which alien plants have spread from an old roadside into three sclerophyll forest communities was measured at a new dam site in Victoria, Australia. The data are discussed in terms of the possible spread of weeds at sites disturbed by the dam construction and subsequent tourist activities.The frequency of alien plants in the forests declines with increasing distance from the road, and was correlated with the reduction in diffuse light. Wetter communities were more heavily colonized than drier communities.Rubus procerusP. J. Muell. andHypochoeris radicataL. were the most successful colonizers.R. procerus, which has become a major weed in the area, was most common near wet sites such as gullies and old water races formerly used for gold mining.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00388.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Summary:The metabolism of cyanazine (2‐chloro‐4‐(1‐cyano‐1‐methyl‐ethylamino)‐6‐ethylamino‐ 1,3,5‐triazine) by corn (Zea mays, L.), fall panicum (Panicum dichotomiflorumMichx.), and green foxtail (Setaria viridisL.) was compared. Cyanazine metabolism by plants at the four‐leaf stage was examined by thin‐layer chromatography following foliar or root treatments with14C‐cyanazine. Five days following foliar14C‐cyanazine applicalion, fall panicum and green foxtail contained a larger number of water‐ and chloroform‐soluble metabolites than corn, whereas, following root treatment, the opposite was true. Corn rapidly hydrolysed the nitrile group and hydroxylated the two‐position on the triazine ring. Accumulation of the dealkylated cyanazine was evident in green foxtail, the most susceptible of the species studied. Metabolism of cyanazine supplied to the roots appeared to differ from foliar treatments in the weed species as more unchanged cyanazine was recovered. Rapid metabolism of cyanazine by corn roots provided evidence for an active cyanazine

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00389.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Summary:The chlorophyll production of wheat (Triticum vulgareL. cv. Mericopa), corn (Zea maysL. cv. Everta), and alfalfa (Medicago sativaL. cv. Saranac), treated with the herbicide 4‐chloro‐5‐methylamino‐2‐(3‐trifluoro‐methylphenyl)pyridazin‐ 3‐one (norflurazon) and grown under high light intensity (10 760 lux) was markedly reduced. Corn and wheat seedlings germinated and grown for 7 days in an agar medium containing 1 mg/1 norflurazon were almost completely bleached. Alfalfa was even more sensitive to norflurazon, 0.1 mg/1 causing almost complete chlorosis. Under low light intensity (10.76 lux) the influence of norflurazon on chlorophyll production was greatly reduced. It is thought that norflurazon inhibits carotenoid synthesis leaving the chlorophyll of the plant subject to photooxidation. Electron micrographs of chloroplasts from green, partially bleached, and bleached areas of corn leaves treated with norflurazon indicate that the herbicide causes progressive deterioration of th

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00390.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Summary:The persistence of TCA in soil was examined using the pyridine‐alkali colorimetric procedure. Loss of TCA was essenlially similar when determined by colorimetry, chloride release or bioassay.Persistence of TCA when incubated with soil at 25°C or sprayed on the soil surface in the field was slightly influenced by soil type.Degradation of TCA occurs largely by microbial action after a lag phase. Soils treated with TCA acquire the ability to degrade further additions of ihe compound without a lag phase. The three soils examined still possessed this ability to differing extents 32 months after they had been sprayed once with TCA at the rate of 22.4 kg/ha. In one experiment the persistence of TCA was shortened appreciably in a plot that had twice previously been sprayed with T

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00391.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Summary:The absorption and loss of four chloro‐s‐triazines was investigated in excised roots of four Setaria taxa. Different taxa absorbed the various triazines at different rates. In general, triazine absorption was greater at 2°C than at 22.5°C, and absorption rates were linear functions of external concentrations.Efflux studies showed marked differences in the rate of loss of14C‐atrazine,14C‐simazine, and14C‐propazine from root sections of robust white foxtail (Setaria viridis var. robustaalbaSchreiber). The roots lost14C‐atrazine very quickly, and the loss was similar in either water or12C‐atrazine. Atrazine appears to be restricted to the apoplast of the root.14C‐atrazine was lost more rapidly than either14C‐simazine or14C‐propazine to water or to solutions containing the unlabelled herbicide. Efflux of14C‐simazine was greater than that of14C‐propazine to solutions of CaCl2. From the pattern of efflux, it was concluded that14C‐simazine and14C‐propazine accumulated in the root symplast. Furthermore, the decreases in chloro‐s‐triazine absorption in the presence of metabolic inhibitors (dinitrophenol, sodium arsenite) may suggest that14C‐simazine and14C‐propazine entered the sy

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1976.tb00392.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY