Estudos sobre o «vermelhão» do algodoeiro (III)

In several cotton crops areas of the State of S. Paulo it was observed, during the years of 1948, 1949, and 1951, the appearance of a purple color of the leaves; the color appears in the opening of the bolls and was correlated with a decrease of production. The opinions concerning the cause of such abnormality were very different and sometimes contradictory; certain investigators attributed the disease to insect attack, others to bad climatic conditions whereas others to a potassium deficiency now called "fome de potássio" (potash hunger); our ideas on the subject is another one. We think that the disease is caused by lack of a suitable supply of magnesium. This opinion is largely based on the syntomatology found in the literature. To study the problem, several experiments were carried out, namely: 1. pot experiments using soil collected in areas where the disorder had appeared; 2. pot experiments controlling the water supply; 3. sand culture experiments omitting either potassium or magnesium; 4. leaf analysis of plant matrial collected troughout the Piracicaba County; 5. plot experiments with the varieties Texas, Express, and I.A. 817 Campinas. The first four experiments were discussed elsewhere. To study the point 5 an experiment was carried out, with the following treatments : 1 - NPKCaMg (no K added) - Mg supplied as MgSO4 (a soluble form); 2 -NPKCa (no Mg added); 3 -NPKCaMg (complete) - Mg supplied as MgSO4; 4 - NPKCaMg (complete) - Mg supplied as dolomitic limestone (a slightly soluble form) as a rate 2.5 higher than in the treatment 1 and 3. Organic matter as cottonseed meal was applied in the proportion of 500 kg per hectare. The experimental design was randomized blocks with 4 replications and the results can be summarized as follows: 1 the I.A 817 variety was the most strongly affected by the physiological disorder, with severe decrease in yield; 2. the disease occurred more frequently in the minus magnesium treatment; 3. dolomitic limestone is so effective as magnesium sulfate in the control of the disease as well in the raising of the yield; 4. in the minus K treatment it was observed a marked occurrence of the typical symptoms of potassium deficiency (cotton rust); 5. magnesium was actually, in the experimental conditions the responsible for the purple color (vermelhão) of the cotton leaves.

Estudos sôbre a alimentação mineral da mandioca (Manihot utilissima Pohl.)

1. The present work was carried out to study the effects of mineral nutrients in the yield as well as in the composition of cassava roots. The variety "Branca de Sta. Catarina" was grown by the sand culture method, the following treatments being used: N0 P0 K0, N0 P1 Kl, N1 P0 K1, N2 P1 K0, N2 P1 K1, N1 P2 K1, and N1 P1 K2, where the figures 0, 1, and 2 denote the relative proportion of a given element. The nutrients were given as follows: N = 35 grams of ammonium nitrate per pot loaded with 120 pounds of washed sand; P1 = 35 grams of monocalcium phosphate; Kl = 28 grams of sulfate of potash. Besides those fertilizers, each pot received 26 grams of magnesium sulfate and weekly doses of micronutrients as indicated by HOAGLAND and ARNON (1939). To apply the macronutrients the total doses were divided in three parts evenly distributed during the life cycle of cassava. 2. As far yield of roots and foliage are concerned, there are a few points to be considered: 2.1. the most striking effect on yield was verified when P was omitted from the fertilization; this treatment gave the poorest yields of the whole experiment; the need of that element for the phosphorylation of the starchy reserves explains such result; 2.2. phosphorus and nitrogen, under the experimental conditions, showed to be the most important nutrients for cassava; the effect of potassium in the weight of the roots produced was much less marked; it is noteworthy to mention, that in absence of potassium, the roots yield decreased whereas the foliage increased; as potassium is essential for the translocation of carbohydrates it is reasonable to admit that sugars produced in the leaves instead of going down and accumulate as starch in the roots were consumed in the production of more green matter. 3. Chemical analyses of roots revealed the following interesting points: 3.1. the lack of phosphorus brought about the most drastic reduction in the starch content of the roots; while the treatment N1 P1 K1 gave 32 per cent of starch, with NI PO Kl the amount found was 25 per cent; this result can be explained by the requirement of P for the enzymatic synthesis of starch; it has to be mentioned that the decrease in the starch content was associated with the remarkable drop in yield observed when P was omitted from the nutrient medium; 3.2. the double dosis of nitrogen in the treatment N2 P1 K1, gave the highest yields; however the increase in yield did not produce any industrial gain: whereas the treatment N1 P1 K1 gave 32 per cent of starch, by raising the N level to N2, the starch content fell to 24 per cent; now, considering the total amount of starch present in the roots, one can see, that the increase in roots yield did not compensate for the marked decrease in the starch content; that is, the amount of starch obtained with N1 P1 K1 does not differ statistically from the quantity obtained with N2 P1 K1; as far we know facts similar to this had been observed in sugar beets and sugar cane, as a result of the interaction between nitrogen and sugar produced; the biochemical aspect of the problem is very interesting: by raising the amount of assimilable nitrogen, instead of the carbohydrates polymerize to starch, they do combine to the amino groups to give proteinaceous materials; actually, it did happen that the protein content increased from 2.91 to 5.14 per cent.

Nitrificação e aproveitamento de alguns adubos nitrogenados

The rate of nitrification of several nitrogenous fertilizers (ammonium sulfate, nitre-chalk, ureia, and cottonseed meal) was studied in three soils, namely, "terra roxa legítima", a red soil derived from basalt, "terra roxa misturada", a soil also derived from basalt but with a higher proportion of sand, and "areito Corumbataí", a sandy soil. The effects of the following treatments on nitrification were considered: addition of limestone of micronutrients (Fe, Cu, Zn, Mn, and Mo), and inoculation with a suspension of spores of Aspergillus wentii, a heterotrophic nitrifier. The results showed that: in "terra roxa legítima" limestone had no influence on the nitrification rate, whereas the micronutrients estimulated the oxidation of nitre-chalk, cottonseed meal and urea; inoculation with A. wentii helped only the nitrification of ammonium sulfate and of the cottonseed meal; the latter, in all the treatments employed gave use to a smaller amount of nitrates; in "terra roxa misturada", all the fertilizers depending upon the treatments they were subjected to, presented maximum values for nitrification; limestone estimulated the oxidation of ammonium sulfate as well as the mineralization of the cottonseed meal; the addition of micronutrients helped the nitrification of all the fertilizers, except that of urea; inoculation showed a benefical influence on the nitrification of ammonium sulfate and cottonseed meal; in "arenito de Corumbatai", the amounts of nitrates produced was roughly the same for all the fertilizers investigated; limestone estimulated the nitrification of nitro-chalk, ammonium sulfate and cottonseed meal whilst the addition of micronutrients benefited only the latter two; the inoculation with A. wentii helped the oxidation of all the fertilizers. In order to study the availability of the various fertilizers above discussed, two plant growing experiments were carried cut, one in pots, using the three soil types and another one in the field, with "terra roxa misturada". In "arenito de Corumbatai" there was no significant difference in the yield both of straw and rice grains for none of the fertilizers: Chilean nitrate of soda was used as a control; ho marked agreement could be detected between the data concerning nitrification and the yield results. In "terra roxa legítima", ammonium sulfate won the competition and there was a good parallelism between nitrification and yield. In "terra roxa misturada", there was no statistical difference among the various fertilizers; the agreement between nitrification and yields was reasonable. In the field (corn), Chilean nitrate, ammonium sulfate and nitro-chalk were clearly beter than urea and cottonseed meal which did not differ from the minus nitrogen plots.

A raspa de mandioca como sucedâneo dos farelos de trigo na alimentação de pintos

In a feeding trial cassava root meal was used as a substitute for wheat bran and wheat middling (mixed) in several ranges: 10, 15, 20 and 30% of a ration. Five groups of 32 seven day old Rhode I. Red chicks were used during 6 weeks of the trial. The results are shown in the Tables (Quadros) I, II and III. Table I shows an high mortality in R4, receiving 30% of cassava root meal and no wheat by product. It was observed a depression of the development of the chicks that was so much high as the proportion of the cassava meal increased in the ration consumed. The A. suggests cassava root meal might have an antagonistic factor acting as a "toxic", that he imagine could be corrected by a higher vitaminic and mineral proportion. This hipothesis must be investigated.

Crescilin (suplemento de penicilina G procaína cristalina) na alimentação de leitões

The A. studied the use of "crescilin", a residual byproduct of penicillin manufacture. It has been recommended the proportion of 1 per cent and proclaimed to supply 400,000 U. O. per kg. The results obtained permited to conclude that 1 per cent of crescilin did not increase the growth of pigs.

Emprego de fezes de pintos na alimentação de leitões

The author studied the application of chick's feces from battery brooder in the feeding of weaning pigs. He employed a basal ration and substituted 5%, 10% and 15% of that basal ration with similar proportions of chicks' feces. He did not observe statistical significance among the treatments. The results measured in terms of average daily gain and feed conversion indicated that the substitution of 5% to 10% by equal proportions of chicks' feces produced satisfactory results, the 5% proportion being the most advantageous.

Aspectos da biologia reprodutiva de Bothrops jararaca em cativeiro (Serpentes, Viperidae)

The reproduction of Bothrops jararaca (Wied, 1824) in captivity in ordened to determine the intercourse period, births, number of neonates, proportion of males and females per litter were performed between 1989 and 1999. Fifty eight females were observed, 16 intercourses in captivity, 45 females arrived already fertilized from nature and 53 litters, resulting on the birth of 426 live neonates, 67 infertile egg masses, 18 stillborn neonates and 4 abnormal neonates. The intercourse period was from february to december and the births happened between february and may. From the two gestacional periods observed, the shortest one was 152 days and the longest 239. The average amount of live neonates per litter was 8,04. Among 323 neonates, 47,68% were males and 52,32% were females. During the first year of life, 75,71% of the females and 71,54% of the males died, and 2,31% of the females and 0,81% of the males reached the fifth year of life.

Resistencia a la enfermedad de cría yesificada por colonias de Apis mellifera con eficiente comportamiento higiénico (Hymenoptera, Apidae)

In an apiary composed of 14 hygienic and 7 non-hygienic colonies of Apis mellifera Linnaeus, 1758 the presence of visible and capped mummies was recorded, one hygienic and 4 non-hygienic colonies showed symptoms of chalkbrood. Twenty-eight days after a massive contamination of the colonies with pollen patties containing Ascosphaera apis Olive & Spiltoir, 1955, the situation was almost identical to that at the beginning: the same 4 non-hygienic colonies still were infected and one hygienic colony that was healthy became infected. The high proportion of hygienic colonies that eliminated the disease symptoms suggests that they could maintain themselves healthy in spite of the presence of colonies with chalkbrood in the apiary.

Abundância de microartrópodes do solo em fragmentos de mata com araucária no sul do Brasil

The abundance of soil microarthropods from seven fragments of Araucaria Forest, Muitos Capões, Rio Grande do Sul, Brazil, was compared. The size of the fragments ranged from 0.25 ha to 35 ha, the two largest fragments are situated within the Aracuri Ecological Station and the remaining five are situated in a cattle ranching farm. In June 2000, three plots (10 m x 10 m) were established in the central area of each patch, and three soil cores (7 cm diameter x 6 cm deep) were taken per plot. The abundance of microarthropods in the upper six centimeters (soil + litter) varied between 63209 and 102704 ind.m-2, with oribatid mites (Acari, Cryptostigmata) being dominant in all fragments (between 46.9 % and 61.3 % of total individuals). Most microarthropod groups presented a decrease in abundance with decreasing fragment area, with a statistically significant difference between smaller and larger fragments. The proportion of oribatids also decreased with decreasing fragment area. The results suggest that the growing fragmentation process of Araucaria forests in southern Brazil, associated to a tendency for reducing the size of remnant fragments, can affect the abundance of soil microarthropods, and therefore, the quality and health of this ecosystem.

Buccal apparatus and gastrointestinal tract dimensions associated to the diet of early life stages of Centropomus undecimalis (Centropomidae, Actinopterygii)

The present study aims to compare the buccal apparatus and gastrointestinal tract of early life stages of Centropomus undecimalis (Bloch, 1792), and relate them to its diet. A total of 190 individuals collected with a channel net in the Catuama estuary (07º40'9.9''S, 34º50'36.7''W), northern coast of the state of Pernambuco, were examined. Morphometrical and meristic data were analyzed for the two initial developmental periods (larval and juvenile). Their digestive tube was morphologically characterized and its content identified. The longest transverse axis of food items was measured, and compared to the standard length (SL) and mouth gape size (D) of the individuals. Body measurement regressions differed significantly (p<0.001) between larvae and juveniles. The stomachs with food content (n=118 individuals) presented a proportion of 62% full and 30% empty (being 8% damaged). They differed in relation to the fullness level and presented a coiled shape when empty. The number of food items in relation to SL and D did not present an evident correlation. Larvae (SL<10 mm) feed on small copepods, while juveniles (SL=11.1 to 64.7 mm) ingest larvae of various decapod species, showing a distinct diet between these initial developmental stages.

Effects of anthropogenic impacts on benthic macroinvertebrates assemblages in subtropical mountain streams

The nature of the riparian and surrounding landscape has been modified by anthropogenic activities, which may subsequently alter the composition and functional structure of macroinvertebrate assemblages. The effect of these changes on function of benthic fauna is difficult to assess due to the scarce knowledge on functional structures in tropical streams. In this study we evaluate whether sites impacted and unimpacted by anthropogenic alterations differed in assemblage composition and density, richness and diversity of each functional feeding group. The selection of the sites was related to their distinct riparian characteristics, following the QBRy riparian quality index. Collector-gatherer was the dominant functional feeding group, comprising 91% of total density, whereas the proportion of shredders was very low, representing less of 0.5% of total density. Asemblage composition of macroinvertebrates differed between impacted and unimpacted sites. Predators were dominant in taxa number, representing about 60% of total taxa richness. In addition, the diversity and richness of collector-gatherers differed significantly between degraded and unimpacted sites, reflecting the sensitivity of this group to environmental changes and the utility to be used in the assessment of anthropogenic modifications. The results of this study reinforce the idea that riparian corridor management is critical for the distribution of macroinvertebrate assemblages as well as functional organization of lotic streams.

The diet of the black widow spider Latrodectus mirabilis (Theridiidae) in two cereal crops of central Argentina

The spider Latrodectus mirabilis (Holmberg, 1876) is commonly found in cereals crops of central Argentina. We studied its diet composition at the field and capture rate on leaf-cutting ants based on laboratory experiments. This study comprises the first approach that documents the diet of L. mirabilis in wheat and oat fields of central Argentina. We identified 1,004 prey items collected from its webs during the last phenological stages of both cereal crops. The prey composition was variable but the spiders prey mainly on ants (Formicidae, Hymenoptera), who represented more than 86% of the total. Meanwhile, in the capture rate experiences we registered a high proportion of ants captured by spiders at the beginning of experiences, capturing the half of the ants from total in the first four hours. Summarizing, we reported a polyphagous diet of this spider species in wheat and oat fields. Ants were the most important prey item of this spider, as found in other Latrodectus spiders around the world.

Population biology of the crab Armases angustipes (Crustacea, Decapoda, Sesarmidae) at Brazilian tropical coast

The semi terrestrial crabs are important elements of the fauna of coastal regions. The aim of this study was to analyze the population structure of Armases angustipes (Dana, 1852) at estuaries of the Ariquindá River, considered a non impacted area, and Mamucabas River, considered a few impacted area, on the south coast of state of Pernambuco, Brazil. The species occurred in all months of the year. The number of individuals per month varied, being higher in the months of transition between the seasons. This is probably due to significant seasonal variations of air and burrow temperature and burrow salinity. There was no sexual dimorphism in size of A. angustipes in the mangrove of Ariquindá River, but males were larger than females in the mangrove of Mamucabas River. In both estuaries, the sex ratio did not differ from Mendelian proportion, but showed a deviation for females. The analysis of temporal variation in sex ratio showed significant differences in some months of the year. These variations are due to cyclical events that act distinctly on each sex. In both estuaries, size classes of carapace width were equally represented by both sexes. The ovigerous females of A. angustipes occurred only in some months of the year, especially in summer, in both estuaries. Probably the high phytoplankton productivity observed in summer favors the reproductive activity, since these algae serve as food for the larvae. Specimens of the population of Rio Ariquindá are largest and wider than those of Mamucabas River. This fact, associated with the low abundance of crabs and the lower frequency of ovigerous females observed in Mamucabas River, is an indication that this population may be influenced by the environmental impacts that this estuary has received.

Climate and land-use changes effects on the distribution of a regional endemism: Melanophryniscus sanmartini (Amphibia, Bufonidae)

ABSTRACT Amphibians are the most threatened vertebrate group according to the IUCN. Land-use and land cover change (LULCC) and climate change (CC) are two of the main factors related to declining amphibian populations. Given the vulnerability of threatened and rare species, the study of their response to these impacts is a conservation priority. The aim of this work was to analyze the combined impact of LULCC and CC on the regionally endemic species Melanophryniscus sanmartini Klappenbach, 1968. This species is currently categorized as near threatened by the IUCN, and previous studies suggest negative effects of projected changes in climate. Using maximum entropy methods we modeled the effects of CC on the current and mid-century distribution of M. sanmartini under two IPCC scenarios - A2 (severe) and B2 (moderate). The effects of LULCC were studied by superimposing the potential distribution with current land use, while future distribution models were evaluated under the scenario of maximum expansion of soybean and afforestation in Uruguay. The results suggest that M. sanmartini is distributed in eastern Uruguay and the south of Brazil, mainly related to hilly and grasslands systems. Currently more than 10% of this species' distribution is superimposed by agricultural crops and exotic forest plantations. Contrasting with a recent modelling study our models suggest an expansion of the distribution of M. sanmartini by mid-century under both climate scenarios. However, despite the rise in climatically suitable areas for the species in the future, LULCC projections indicate that the proportion of modified habitats will occupy up to 25% of the distribution of M. sanmartini. Future change in climate conditions could represent an opportunity for M. sanmartini, but management measures are needed to mitigate the effects of habitat modification in order to ensure its survival and allow the eventual expansion of its distribution.

Sobre o preparo dos parasitas da malária em distensões espessas, especialmente em amostras supersecas

I) the A. presents a method developed for the preparation of thick blood films, specially old desiccated smears. The observations are based on the experience of more than 53000 blood samples collected in the laboratory of the “Serviço de Malaria do Nordeste” as well as in the research department of the “Serviço de Malaria da Baixada Fluminenese”. II) As in introductory matter, he emphasizes the value of the obstacles presented by overdrying of the thick blood films occurring systematically in great malaria control organizations in which the laboratory receives materials from more or less remote localities, particularly in the Brazilian northeast, in regions invaded by Anopheles gambiae. III) An analysis of the causes of failure of the methods of Chorine and Knowles recorded in the literature for such purposes is given, as well as its adaptability for the simultaneous preparation of large numbers of samples. IV) The method is based the protective action of a previous fixation by a dilute solution of formalin, which, without preventing further dehemoglobinization, prevents morphological alterations in the parasites by the action of Knowles solution which is retained in this metod without modification. V) For washing out the acids of the dehemoglobinizating solution as well as for diluting the Giemsa stain, the A. proposes a very simple technique, extremely convenient for such purpose, which consists in adding acetic acid to the distilled water in the proportion of 1 drop for each 10cc of water, and then increasing the hydrogeni-on concentration to pH 7.2 with a 2% sol. of sodium carbonate. As indicator a 0.02% solution purple-bromcresol prepared in accordante to Medalia, is used. In this reaction there is the formation of the acetic acid ↔ sodium acetate, buffer system very suitable for giving a convenient pH and for preventing the precipitation of the dye, which can be used for two or three batches of 700 or 800 slides each, without changing the staining solution. VI) – The method can be summarized as follow: For a small number of samples, Coplin’s or any other staining jar can be used. Large number of slides must be placed in groups of 10 or 15 units each, the slides being separated by a piece of cardboard, according to Barber & Komp. A) Fix in dilute formalin (2%), during 5 minutes. b) Without washing, put in Knowles solution (see the formula in the text), no more than 20 minutes. c)Two successive washings in distilled water, buffered as explained above (which can be used several times). d) Dry and stain with Giemsa solution, prepared by using 1 drop of the stain for each c. c. of buffered distilled water. Time: 1 hour. E) Was in distilled water and dry.