Uptake, translocation and metabolism of fluazifop-butyl in Setaria viridis

The uptake and translocation of fluazifop-butyl was investigated in Setaria viridis. Young plants (three to four leaves) with a portion of the second, third or fourth leaf covered, were sprayed with a dose equivalent to 0.25 kg a.i. ha-¹. ¹⁴C-fluazifop-butyl was subsequently applied to the unsprayed area and the treatment resulted in plant death within 2 wk. Uptake by leaf 3 was rapid, with less than 5% of the applied dose remaining on the leaf surface after 24 h. The highest proportion of ^14C-activity was retained in the treated portion of the leaf. Only 2% of the applied dose was translocated from leaf 3 and 0. 76% accumulated in the apical meristem. Uptake by the younger leaf 4 was more rapid and the pattern of translocation differed in that more ¹⁴-^-activity accumulated in apical meristematic tissue. 6–30% of the applied dose was undetected and this was greatest when foliar uptake was slow. Artificial leaf surface experiments indicated that this undetected activity may have been due to volatility of fluazifop-butyl or degradation to volatile products. ^14C-activity extracted from treated leaves was identified as fluazifop-butyl, fluazifop acid and polar conjugates. The major ¹⁴C-activity extracted from the apical meristem was fluazifop acid and no fluazifop-butyl was detected in this extract.     

Corsets,Culture and Contingency: Reflections on Joan Lindsay's Picnic at Hanging Rock1

This article turns an anthropological sensitivity onto a literary text from its own society. It takes Joan Lindsay's novel ‘Picnic at Hanging Rock’ and ‘reads’ it in the light of ideas prominent in recent anthropological writings (the ideas of Lévi-Strauss are particularly used): it also articulates an interpretation by using notions current in modern literary and cultural analysis. The article points out that Lindsay's text has most commonly been interpreted as being about mysterious natural forces injurious to man. Whilst the text explores the disjunction between nature and culture, the article interprets the text as exploring the nature of cultural institutions and cultural processes.     

Poliomyelitis vaccine; a report on field trials in Southern Alameda County in 1954

Southern Alameda County was the only area in California to take part in the 1954 nationwide field trials for testing poliomyelitis vaccine. Besides the contribution made in evaluating the vaccine, other benefits were:1. Participation contributed to the control of a serious communicable disease.2. Inoculations of vaccine during the field trials in all probability prevented some cases of paralytic poliomyelitis among children in southern Alameda County.3. The community became better informed about poliomyelitis and more interested in the local health department.4. Local physicians had an opportunity to contribute to important research and to give a valuable community service.5. The staff of the Alameda County Health Department became better informed and better prepared for any future responsibilities in poliomyelitis immunization programs.Other conclusions reached as a result of participation in the 1954 field trials are that the initial planning of the study was hasty and not sufficiently representative of medical and administrative thinking. If the trials had been planned for 1955 instead of 1954 there would have been sufficient time for research to be completed, professional information to be assured and for sound design of study.     

The causes of colour and colour change in caterpillars of the poplar and eyed hawkmoths (Laothoe populi and Smerinthus ocellata)

Caterpillars of the poplar and eyed hawkmoths (Laothoe populi and Smerinthus ocellata respectively) were reared under different conditions in order to determine why final instar caterpillars vary in colour. Poplar hawkmoth caterpillars normally rest on the undersides of leaves. Dull green and redspotted caterpillars are genetically determined polymorphisms. Caterpillars that are not dull green, however, can become white when fed on Populus alba or yellow-green when fed on Salix fragilis. Experiments showed that it is the reflective qualities of the leaves that determines which colour the caterpillar develops: if the young larva sees white then it becomes white, but if it sees green, grey or black then it becomes yellow-green. Young eyed hawkmoth larvae always developed into grey-green final instar caterpillars under our rather poorly-illuminated rearing conditions, but when reared on wild plants in white muslin sleeves they became whitish-green. In this species also it appears that colour of the final instar is determined by the reflectance of the substrate perceived by the young caterpillar.     

The distribution of Naididae (Oligochaeta) in the littoral zone of selected lakes in North Wales and Shropshire

SUMMARY. The distribution of twenty species of Naididae found in seventeen lakes in North Wales and Shropshire is described. Fewer species were observed in the mountain lakes in Snowdonia in comparison to the more productive lakes of Anglesey and Shropshire.
Substrate was an important factor influencing the distribution of naids within lakes, A small number of sexually mature individuals was found in more productive lakes in the summer and autumn months. Sexually mature individuals of Stylaria lacustris were cultured in the laboratory; the population doubled its numbers, by asexual reproduction, in 12 days at 15°C. In Llyn Coron a natural population of S. lacustris doubled its numbers in 40 days. The gut contents of S. lacustris consisted of periphyton.     

Phosphoenolpyruvate Carboxylase from the Crassulacean PlantBryophyllum fedtschenkoiHametet Perrier: ACTIVITY CHANGES AND KINETIC BEHAVIOUR IN CRUDE EXTRACTS

The total activity (capacity) of phosphoenolpyruvate carboxylasein crude extracts of leaves of Bryophyllum fedtschenkoi, measuredon a fresh weight basis, varies considerably with leaf positionand with photoperiodic treatment. No diurnal variation in capacitywas detected under long – day or short – day conditions.The enzyme in freshly prepared crude extracts is about 50 timesmore sensitive to inhibition by malate at pH 7 than that inaged extracts, or in the fully purified state. Desensitizationin extracts proceeds rapidly unless protective measures aretaken, and appears to be irreversible. A pH-dependence studyshows that the effect of desensitization on the kinetic parametersof malate inhibition is identical to that of increasing thepH by 2.0 units over a wide range, but the maximum velocityat pH 7.8 is virtually unaffected. The significance of the resultsfor both the experimental determination of cyclic changes inenzyme capacity, and the theories concerning the mechanism ofa circadian rhythm of phosphoenolpyruvate carboxylase activityin vivo are discussed.     

Ultrastructure of the Eyespot and its Possible Significance in Phototaxis of Tetracystis excentrica*†

SYNOPSIS. The eyespot of the zoospore of Tetracystis excentrica (a green alga) has been studied by light and electron microscopy. In Tetracystis the eyespot consists of about 110 osmiophilic granules which form a plate in the anterior third of the cell. The granules are about 80 Å in diameter and are found in the outermost portion of the chloroplast; they commonly show hexagonal close packing and a hexagonal shape. The granules are confined positionally by the chloroplast envelope and an inner thylakoid. The plasmalemma over the eyespot is thickened and is separated from the chloroplast envelope by a 50 mμ space. The eyespot of Tetracystis is compared with others reported in the literature and the possible functional significance of these studies is discussed. The possibility that the eyespot plate in Tetracystis serves as a shading device rather than the primary photoreceptor is considered.