82 resultados para 1953
Resumo:
A generalized comprehensive scheme concerning the movement of materials into living cells and tissues is presented. It is designed for use by investigators and teachers who, is assumed, have a previous knowledge of the subject as well as familiarity with previously published literature on the subject. Footnotes to figure 2 X = a constituent component material, arising from extermal sources or through metabolism, capable of migration under favorable conditions. e, i, ec, ic, mc = subscripts indicating location. oC = oxidized cytoplasmic constituents specifically concerned in unidirectional (here invardly directed), diffetial translocation of a particular material X. rC = reduced cytoplasmic constituents specifically concerned. XF = specific free energy (2) of a constituent component in in external or internal phases or in cytoplasm. D = diffusion (4). EA = exchange adsorption (4). MA= metabolic accumulation (4), CI = differentially characteristic cytoplasmic interaction (4) between oC and X, determined by the genetic constitution of the biological species. ▬▬▬>= migration, where permeability to the material involved is relatively high; and ~~~~->, where relatively low. <▬▬▬>= chemical reactions. ▬▬▬>= energy changes of X; diffusion is characteristically with the direction in which the concentration or activity of the constituent decreases, exchange adsorption may be with or against the direction of concentration or activity decrease.
Resumo:
Studying the meiosis of two Hemiptera, mamely, Lybindus dichrous (Coreidae) and Euryophthalmus humilis (Pyrrhocoridae), the author has found new proofs in favor of the existence of a centromere at each end of the chromosomes of the insects belonging to that order. Following the behaviour of a pair of large autosomes of Lybindus, he was able to verify that in the first division of the spermatocytes, the tetrad they form divides transversely by the middle, giving rise to two V-shaped anaphase chromosomes that go to the poles with the vertex pointing forwardly. From the end of the first division till the metaphase of the second one, the centromeres occupying the vertex of the V go apart from one another, making the chiasmata existing there slip to the opposite extremities, what changes the V into an X. When the chiasmata reach the acentric ends, the X is again converted into a V. The V of the secondary metaphase, therefore, differs from the V of the primary anaphase, in being inverted that is, in having the centromeres in the extremity of its arms, and no longer in the vertex as in the latter. The opening out of the chromosomes starting at the centric extremities in order to recuperate the dumbbell shape they show in the secondary anaphase, just in the manner postulated by PIZA, is thus demonstrated. In Euryophthalmus humilis it was verified once more, that the heterochromosome, in the secondary spermatocytes, orients parallelly to the spindle axis, accompanying with its ends the anaphase plates as they move to the poles. The author is in disagreement with NORONHA-WAGNER & DUARTE DE CASTRO's interpretation of the behaviour of the chromosomes in meiosis of Luzula nemorosa.
Resumo:
Biology of Arsenura xanthopus (Walker, 1855) (Lep., Adelocephalidae), a pest of Luehea spp. (Tiliaceae), and notes on its natural enemies. In the beginning of 1950, one of the Authors made some observations about the biology of Arsenura xanthopus (Walker), in Piracicaba, State of S. Paulo, Brazil. From 1951 to 1953, both Authors continued the observations on such an important Adelocephalidae, the caterpillars of which represent a serious pest of Luehea spp. leaves. Actually, in some occasions, the caterpillars can destroy completely the leaves of the trees. The species is efficientely controlled by two natural enemies: an egg parasite (Tetrastichus sp., Hym., Eulophidae) and a fly attacking the last instar caterpillar (Winthemia tricolor (van der Wulp), Dip., Tachinidae). Tetrastichus sp. can destroy 100% of the eggs and the fly, 70 to 100% of the caterpillars. Indeed, facts as such are very interesting because we rarely know of a case of so complete a control of a pest by an insect. A. xanthopus had not yet been mentioned in our literature. Actually neither the systematic bibliography nor the economic one has treated of this species. However, a few other species of Arsenura are already known as living on Luehea spp. According to the Authors' observations, W. tricolor was also unknown by the Brazilian entomological literature. Arsenura xanthopus (Walker, 1855) After giving the sinonimy and a few historical data concerning the species, and its geographical distribution, the Authors discuss its placing in the genus Arsenura Duncan or Rhescyntis Huebner, finishing by considering Arsenura xanthopus as a valid name. The Authors put the species in the family Adelocephalidae, as it has been made by several entomologists. The host plant The species of Tiliaceae plants belonging to the genus Luehea are called "açoita-cavalo" and are well known for the usefulness of their largely utilized wood. The genus comprises exclusively American plants, including about 25 species distributed throughout the Latin America. Luehea divaricata Mart, is the best known species and the most commonly cultivated. Biology of Arsenura xanthopus Our observations show that the species passes by 6 larval stages. Eggs and egg-postures, all the 6 instars of the caterpillars as well as the chrysalid are described. The pupal period is the longest of the cycle, taking from 146 to 256 days. Data on the eclosion and habits of the caterpillars are also presented. A redescription of the adult is also given. Our specimens agreed with BOUVIER's description, except in the dimension between the extremities of the extended wings, which is a little shorter (107 mm according to BOUVlErVs paper against from 80 to 100mm in our individuals). Winthemia tricolor (van der Wulp, 1890) Historical data, geographical distribution and host are first related. W. tricolor had as yet a single known host-; Ar^-senura armida (Cramer). This chapter also contains some observations on the biolcn gy of the fly and on its behaviour when trying to lay eggs on the caterpillars' skin. The female of W. tricolor lays from 1 to 33 eggs on the skin of the last instar caterpillar. The mam region of the body where the eggs are laid are the membranous legs. Eggs are also very numerous oh the ventral surface of the thorax and abdomen. The. preference for such regions is easily cleared up considering the position assumed by the caterpillar when fixed motionless in a branch. In such an occasion, the fly approaches, the victim, puts the ovipositor out and lays the eggs on different parts of the body, mainly on the mentioned regions, which are much more easily reached. The eggs of the fly are firmly attached to the host's skin, being almost impossible to detach them, without having them broken. The minute larvae of the fly enter the body of, the host when it transforms into chrysalid. Chrysalids recentely formed and collected in nature f requentely show a few small larvae walking on its skin and looking for an adequate place to get into the body. A few larvae die by remaining in the skin of the caterpillar which is pushed away to some distance by the active movements of the chrysalid recentely formed. From 1 to 10 larvae completely grown may emerge from the attacked chrysalid about 8 days after their penetrating into the caterpillars' body and soon begin to look for an adequate substratum where they can transform themselves into pupae. In natural conditions, the metamorphosis occurs in the soil. The flies appear within 15 days. Tetrastichus sp. This microhymenoptera is economically the most interesting parasite, being commonly able to destroy the whole pos^ ture of the moth. Indeed, some days after the beginning of the infestation of the trees, it is almost impossible to obtain postures completely free of parasites. The active wasp introduces the ovipositor into the egg of the moth, laying its egg inside, from 80 to 120 seconds after having introduced it. A single adult wasp emerges from each egg. Sarcophaga lambens Wiedemann, 1830 During the observations carried out, the Authors obtained 10 flies from a chysalid that were recognized as belonging to the species above. S. lambens is a widely distributed Sarcophagidae, having a long list of hosts. It is commonly obtained from weak or died invertebrates, having no importance as one of their natural enemies. Sinonimy, list of hosts and distribution are presented in this paper. Control of Arsenura xanthopus A test has been carefully made in the laboratory just to find out the best insecticide for controlling A. xanthopus caterpillars. Four different products were experimented (DDT, Pa-rathion, BHC and Fenatox), the best results having been obtained with DDT at 0,25%. However, the Authors believe in spite of the initial damages of the trees, that the application of an insecticide may be harmful by destroying the natural agents of control. A biological desiquilibrium may in this way take place. The introduction of the parasites studied (Tetrastichus sp. and Winthemia tricolor) seems to be the most desirable measure to fight A. xanthopus.
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This paper deals with the preliminary results of a sand culture experiment carried out to obtain physiological bases to study the fertilization of cassava in the State of São Paulo. On the other hand, the authors are interested in the possible influence of mineral nutrients in the quantity and quality of starch. Cassava (Manihot utilissima Pohl.), "Branca de Sta. Catarina" variety, was grown under the following treatments: NO PO KO, NO P1 K1, N1 P0 Kl, NI P1K0, N2 p1 Kl N1 P2 K1 and N1 P1 K2. A striking response to phosphorus was observed among the treatments. However, once secured the necessary phosphoric level to the plant, the production becomes limited by nitrogen; in other words, increase in yield can be accomplished only by raising the nitrogenous level. The present results suggest that the remarkable effects of phosphates applied to cassava cultures in the State of São Paulo are due not only to the poor quality of our soils, as far phosphorus is concerned: we are facing a positive physiological response showed by the plant.
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The authors repport in this paper, the results of trials by means of which were determined the composition and nutritive value of Capim Jaraguá, Hyparrhenia rufa (Nees) Stop/, cultivated in Piracicaba, in State of São Paulo, Brazil. The experiments were made with hay, silage and also the grass at three different stages: before, during and after blooming. The digestion trials were carried out with sheep, following the technique of MEAD and GUILBERT. The chemical analysis of the forages were made by methods usually employd. The results are in the table XXIV e XXV of this paper.
Resumo:
The present paper relates a few experiments carried out to study the distribution of radiozinc in tomato seedlings as well its translocation in adult plants. 1 Tomato seedlings grown in nutrient solution were given during two weeks ca. 0.2 microcuries of Zn65C112; the seedlings were then harvested, and after careful washing of the roots with distiled water and diluted HC1, a radioautograph was taken (Fig. 1); this shows that the whole seedling, including the first cotyledon leaves are active; the Zn65 is preferentially concentrated, however, in the root system; this fact suggests that finding by ROSSITER (1953) that the roots of plants growing under natural conditions had a very high concentration of zinc is not due to soil contamination being ascribable to the physiology of such micronutrient. 2. The translocation of radiozinc was demonstrated by three different ways. In the first case, Zn65Cl2 was supplied to the nutrient solution during four weeks; three weeks after the addition of the radiozinc was discontinued, the newer leaves were detached and a radioautograph was taken (Fig. 2); the activity therein found shows that translocation occurred from the old leaves to the young ones. In the next experiment, identical procedure was followed but, instead of a radioautograph, different parts of the plant were ashed and counted; it was verified that 66.6 per cent of the activity supplied was absorbed; due to a great fixation within the roots only 5,6 per cent was translocated to the newer organs. In the third trial, Zn65C12 was directly applied to both upper and lower surfaces of medium aged leaves; counting the separated organs revealed that: 24.2 per cent of the activity applied hab been absorbed; however, 13.7 per cent translocated to the rest of the plant including to the roots. The author wishes to express his gratitude to Dr. P. R. Stout, Chairman, Dept. of Plant Nutrition, University of California, Berkeley and to Mr. A. B. Carlton for their help during part of this work. O autor agradece ao Laboratório de Isótopos da Universidade de São Paulo, na pessoa do Dr. T. Eston, o fornecimento do Zn65 usado neste trabalho.
Resumo:
The aim of this paper is the study of moon effects on ten different crops divided in four groups: 1) salad and cole crops (lettuce, endive, cabbage, cauliflower); 2) root crops (beet, carrot, radish, turnip); 3) bulb crops (onion); 4) solanaceous fruits (eggplant). The design of the experiment was randomized blocks, with four replications, the different treatments being the four phases of the moon. The analyses of variance are given in the work of Simão (1953) and the analises of the mean in tables 1 to 2. The main conclusions are: 1) No difference in production were found related to different moon phases, even it the crops supposed to be sensible to moon effects. 2) In a few cases, where some increase in production was observed, such increase could be atributed by other apents 3) The agents supposed to interfere with increase in production were temperature and photoperiodism, rather than moon phases. 4) The most sensible crops to low temperature, during the night, were: lettuce, endive, cauliflower, cabbage, carrots, turnips and radish. 5) The most sensible crops to both low temperature and photoperiodism were: onion and beet. 6) The moon phases supposed to have opposed effects, namely full-moon and half-moon, gave mixed results sometimes both giving the best yield simultaneously and sometimes giving the poorest crops. 7) As a final conclusion, no moon effects could be detectable in the present experiment.
Resumo:
Seven species of the nematode genus Mononchus Bastian, 1865, were found in the State of São Paulo, Brazil. Such are: M. subsimilis Cobb, 1917; M. ibitiensis Carvalho, 1951; M. piracicabae Lordello, 1953; M. risoceiae Carvalho, 1955; M. soutoi Carvalho, 1956; M. coronatus Carvalho, 1956; and M. jairi n. sp. Outside the State, the following species have been found: M. papillatus (Bastian, 1865) Cobb, 1916; M. monhystera Cobb, 1917; M. muscorum (Dujardin, 1845) Cobb, 1916; M. gymnolaimus (Cobb, 1893) Cobb, 1916; M. consimilis Cobb, 1917; M. trichurus Cobb, 1917; M. reversus Cobb, 1917; and M. dentatus Cobb, 1917 (LORDELLO, 1953). This field of investigation has scarcely been touched and additional collections will doubtless add new forms to the number of species known as yet. M. jairi n. sp. most closely resembling species is M. monhystera Cobb, 1917, from which it differs in having: a) labial region more expanded, set off from neck by a broad shallow depression; b) anterior portion of the pharynx-wall rather thinner and directed outward; and, c) smaller dimensions (788.0-924.0: 1,100.0 micros).
Resumo:
The authors discuss a formula for the determination of the most profitable level of fertilization (x*). This formula, presented by CAREY and ROBINSON (1953), can be written as: x*= (1/c) log cx u L10 + (1/c) log wu _______ ___ 1-10 x u t being c the growth factor in Mitscherlich's equation, x u a standard dressing of the nutrient, L 10 the Naeperian logarithm of 10, u the response to the standard dressing, w the unit price of the crop product, and i the unit price of the nutrient. This formula is a modification of one of the formulas of PIMENTEL GOMES (1953). One of its advantages is that is does not depend on A, the theoretical maximum harvest, which is not directly given by experimental data. But another advantage, proved in this. paper, is that the first term on the right hand side K= 1(/c) log cx u L 10 ____________ 1 - 10-cx u is practically independent of c, and approximately equivalent to (1/2) x u. So, we have approximately x* = (1/2) x u + (1/c) log wu . ____ x u t With experimental data we compute z = wu ____ x u t then using tables 1, 2 and 3, we may obtain Y - (1/c) log z and finally x* = (1/2) x u + Y. This is an easy way to determine the most profitable level of fertilization when experimental data on the response u to a dressing x u are available. Tables for the calculation of Y are included, for nitrogen, phosphorus, potash, and manure.
Resumo:
During 1952 and 1953 the author observed that radish, Raphanus sativus, L, developed rapidily in the warmer and damper period of the year and endured the lower temperatures. The yiel of leaves counted from 20 to 40% of the plant weigth.
Resumo:
The author carried out a study on the behavior of cabbage for a period of two years (1952 and 1953). From the results obtained it was concluded that, cabbage, Brassica oleraceae, var. capitata, developed better during the cooler season of the year, that is, from April to June and, the yield decresed from the beginning to the end of the sowing time, that is, from April to Ocotber.
Resumo:
At the 2nd. Department of Zootechny of the E. S. A. L. Q., in Piracicaba, between 1953 and 1955 an experiment of sugar cane varieties was carried out, with the objective of discovering varieties to substitute "Taquara" (the variety most widely used) and Co 290 (the most recommended). The former was condemned as being too susceptible to cane smut and the latter showes signs if degeneracy. In the experiment, 8 varieties were used with 3 replications in randomized blocks, in 3 rows each. The cane was crop not in the same period, but when they were at comparable ripeness (70 cm of apparent culm). They were crop twice during the year, with a sharp hoe near the soil. The summary of the results and the statistical analyses are shown in tables 1 to 3, showing the possibility of there being 3 groups: A superior one composed of Co 419, a median one, in decreasing order of production, composed of Kassoer, CB 40-69. Co 413, IAC 36-25 and POJ 161 and an inferior group composed of Co 290 and Taquara. There is a possibility that POJ 161 belongs to the last group. Nevertheless, this variety is not recommend because of its susceptibility to smut. As Kassoer is more healthy, vigorous and enduring than Co 419 and other varieties, it is shown recommendable. IAC 36-25 is being recommended presently for forage since its productions is lower than Kassoer, placing 5th productivity, although statistical significance was not detected. As our final conclusions, Co 419, Kassoer, CB 40-69, Co 413 and IAC 36-25 can be planted as forage while POJ 161, Co 290 and Taquara should not. The last two were exactly those used as forage reserve in the 2nd. Department at the beginning of the experiment.