Changes in levels of abscisic acid (ABA) and cytokinin activity in the xylem sap of willow (Salix viminalis, L) were folHowed throughout two growth cydes.Growth in spring was preceded by decreasing levels of ABA and an increase in cytokinin activity. The onset of dormancy was associated with low levels of cytokinins and high contents of ABA. A second peak of ABA was found in July which was not related to the dry weight of the sap. The main cytokinin activity in the sap was due to a zeatin ribosidelike compound.

Abstract.Brazil accounts for about 20% of the world production of cocoa, and about 95% of cocoa produced in Brazil is from the southeastern part of Bahia State. Traditionally, cacao is grown in monoculture (though under the shade of various other species). But various crop combinations involving cacao have recently been undertaken by the farmers with encouragement from Brazilian government.As a part of the crop diversification programme in the traditional cacao growing areas and their surroundings, extensive areas are being planted to other plantation crops, mainly clove and rubber and, to some extent, coconut too. Crop combinations have been adopted in some of these new plantings and cacao is an important component of most of such combinations. Whereas several other crops are combined with clove trees, cacao is usually the only species grown with mature rubber trees. Young rubber trees are, however, interplanted with a number of other species. Productive coconut areas are found mostly in sandy soils along the coast so that there is little intercropping. However, scattered farms are found where coconuts are underplanted with guarana, black pepper, cacao, cashew, etc. as done commonly in other parts of Northeast Brazil.The paper presents some data on the performance of some of the combinations involving cacao and other plantation crops based on field survey, and discusses the potentials and constraints of extending the system to more areas in the region.

Resumo A participação feminina na atividade pesqueira representa uma alternativa de subsistência, fonte de trabalho e renda para inúmeras famílias em todo o país. Todavia, a atuação da mulher neste universo ocorre, com algumas exceções, num contexto de invisibilidade e desvalorização do seu trabalho, entendido, muitas vezes, como extensão das tarefas domésticas, e não como pesca propriamente. Contrariando este contexto, destaca-se um grupo de pescadoras da comunidade Ilha do Beto, localizada no município de Itaporanga D’Ajuda, Sergipe, Brasil. O presente trabalho é um estudo de caso e tem por finalidade revelar as distintas atribuições dessas mulheres e as características de sua atuação na pesca artesanal. Para alcançar o objetivo proposto, a metodologia utilizada fundamenta-se na abordagem qualitativa. Foram também adicionados à estrutura metodológica pressupostos da história oral e aspectos da abordagem etnográfica. A elaboração deste estudo permitiu apreender que o papel desempenhado por essas pescadoras na aludida comunidade assume uma conotação diferenciada, uma vez que a importância do seu trabalho é reconhecida e assumida por elas. Ademais, foram observadas outras surpreendentes características peculiares ao grupo, tais como dependência masculina em relação à mulher para realização da atividade pesqueira; inexistência de atribuições ocupacionais distintas entre os gêneros, constatadas a partir da presença da mulher nas embarcações, desempenhando funções também no mar, entre outras.

Introduction Proper storage conditions and maintenance of viable biological material plays an important role in microbiological research, allowing for the opportunity to conduct future studies. Objective To evaluate the viability of Streptococcus mutans strains that were previously grown and stored under different temperatures for approximately eight years. Material and method In this study, we evaluated 393 bacterial isolates that were stored in a freezer at -80°C (G1) and 200 isolates stored in a freezer at -20°C (G2). Aliquots of each sample were plated on blood agar and mitis-salivarius bacitracin sucrose agar-solidified medium. After incubating under microaerophilic conditions in an incubator at 37°C for 72 hours, the presence, morphology and purity of bacterial growth was observed. The data were analyzed by means of descriptive statistics. Result Microbial viability was observed in almost all samples (99.7%) in G1, whereas all isolates stored at -20°C were considered inviable. Conclusion The viability of S. mutans is influenced by the storage temperature of the samples, and the strains remain viable when stored under ideal temperature conditions (-80°C), even when stored for a long period of time.

A series of growth room experiments was carried out aiming to establish the role of abscisic acid on dormancy of Salix viminalis L. The inhibitor content and abscisic acid levels of extracts from roots, sap, leaves, and apical tissues of willow were measured using biological assay and gasliquid chromatography.No evidence was obtained that photoperiodically mediated dormancy is associated with changes in abscisic acid levels or fl-inhibitor activity.Short photoperiods can induce cessation of extension growth, apex abortion, leaf senescence, and the formation of resting structures in willow (1).The involvement of growth hormones in photoperiodically induced dormancy in willow has been recently demonstrated. Higher inhibitory activity and lower levels of auxin and gibberellin-like substances were detected by the wheat coleoptile, oat mesocotyl, and lettuce hypocotyl bioassays in acidic extracts of willow growing points when plants were transferred from long to short days (4). The effect of photoperiod on the inhibitor content of willow has also been investigated in the phloem sap by a number of workers (4, 5, 9), through bioassaying extracts of the "honeydew" exuded from the aphid Tuberolachnus salignus (Gmelin), a higher inhibitory activity being found in short day plants. ABA was shown to be one of the inhibitory substances found in the aphid exudate (1 1).Various attempts to demonstrate changes in inhibitor levels in response to daylength treatments were made in the course of the present work, using the wheat coleoptile bioassay for the estimation of inhibitory activity and GLC for the quantification of ABA in particular.MATERIALS AND METHODS Plant Material. Willow (Salix viminalis L.) rooted cuttings were used throughout this work. Shoot growing points, partially expanded and mature leaves, xylem sap, phloem exudate and also roots from plants given different daylength treatments were analyzed. Shoot growing tips included the apical meristems and all of the enfolding partially expanded leaves, with their internodes, down to the first horizontal leaf of the shoot. Xylem sap was extracted by the method of Bollard (3), from stem segments 80 to 100 cm in length growing either in soil or in tap water. Aphid ' This paper represents part of the Ph.D. dissertation of R. A., whose work was supported by CEPLAC (Brazil), by the "Conselho Nacional de Pesquisas" (Brazil), and by the Ministry of Overseas Development (Great Britain).exudates were collected in aluminum foil, over successive 24-h intervals, from 100-cm cuttings planted obliquely in the soil. Roots were excised from 50-cm leafy cuttings growing in tap water. All plant material had been previously subjected to approximately 2 weeks of long photoperiods (17 h) at 20 C before daylength treatments were applied.Photoperiodic Treatments. The long day treatments always consisted of supplementing the high intensity illumination periods applied in the short day growth cabinets with low intensity light provided by two fluorescent tubes (6.5 lumen/M2 at the shoot ti...

Levels of abscisic acid were followed in the xylem sap, mature leaves, and apices of field-grown willow (Salix vihnalis L.) during the summer months, under natural and artificially extended photoperiods. Although the long day treatment prevented the general onset of dormancy, the plants grown under natural daylengths showed lower concentration of abscisic acid than those kept under long days.Correlations between high ABA levels and the dormant period in woody plants have recently been found in the xylem sap of peach (4) and in buds of apple (6) and birch (5). Marked seasonal fluctuations in ABA content of xylem sap of willow (Salix viminalis L.) which could also be associated with the stage of dormancy were reported by Alvim et al. (2). The concentration found in July, 4 weeks before plants stopped elongating, represents about 10 times that found in spring. Leaf buds opened well after ABA levels started to decrease at the end of December.It is tempting and pertinent to question whether the changes in ABA levels in the summer were caused by the shortening of daylength. It may be relevant that the levels of inhibitory substances in the sap extracts began to increase shortly after the longest day (June 21). Despite the fact that several experiments carried out under controlled environments (1, 3) did not show any evidence of an effect of short photoperiods on the ABA content of willow rooted cuttings, it was decided to attempt to detect possible effects of photoperiodic changes under field conditions. MATERIALS AND METHODSDaylength was artificially extended in part of the same row of trees used in the previous year in the first part of this work (2). A minimum of 17 hr of daily illumination was applied in this treatment, using two fluorescent tubes (6.5 lumen/m at the shoot tip level) standing 20 to 50 cm above the plants.ABA levels from both long-day-treated and control plants were periodically determined by GLC in extracts of the apices, mature leaves, and sap of willow (S. viminalis L.). Xylem sap was obtained by the method described in the first paper in this series (2). Mature 'This paper represents part of the Ph.D. dissertation of R. A

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