Bragantia, Volume: 10, Issue: 3, Published: 1950
  • Adubação do repôlho: Parte I - Experiências preliminares

    Camargo, L. de Sousa

    Abstract in English:

    Cabbage is an important vegetable crop in the State of São Paulo. The present study relates primarilly to the effect of fertilizer applications on the production of cabbage. The tests were carried out both at Tupi and at Campinas Experiment Stations. Under the condition of the these tests very good results were obtained from the following mineral fertilizer application : NPK (5:13:5), applied at the rate of 1,800 kilograms per hectare. (22,000 plants) The best results in terms of cabbage production were obtained by application of a combination of organic and inorganic fertilizers, organic fertilizer being applied in the form of banayard manure (3 000 g) or cotton seed meal (300 g) per plant, and the NPK (7:10:8)being applied at the rate of 1,260 kilograms per hectare.
  • Observações citológicas em Coffea: XV - Microsporogênese em Coffea arabica L.

    Mendes, A. J. T.

    Abstract in Portuguese:

    No presente trabalho são apresentadas as observações realizadas sôbre a microsporogênese nas variedades semperflorens e caturra, de Coffea arabica L. Notou-se que, no início da prófase, os cromossômios se colorem muito mal, não permitindo observações sôbre a sua morfologia; em paquitene, os cromossômios se apresentam com várias secções heteropicnóticas separadas por secções muito finas, que se colorem mal; o centrômero é bastante nítido e se acha ladeado de zonas bem heteropicnóticas; as extremidades dos braços dos cromossômios se colorem mal e se perdem no meio do citoplasma ; o nucléolo é bastante visível e a êle se acham ligados alguns cromossômios. É difícil determinar o número exato de cromossômios ligados ao nucléolo, tendo-se encontrado de 1 a 4. De paquitene a metáfase I, as fases se sucedem rapidamente. Em diplotene, os cromossômios são curtos, não mais se percebendo o centrômero. Em diaquinese os 22 pares de cromossômios se repelem pela sua parte mais colorida, onde se encontra o centrômero, e se unem pela parte clara, onde se notam os quiasmas ; o número de quiasmas, por célula, varia de 29 a 43 ; a média por bivalente é de 1,67, em semperjlorens, e 1,75, em caturra. Em metáfase I, o número médio de quiasmas, por bivalente,. é de 1,69, em semperjlorens, e 1,67, em caturra. Em anáfase I, os 22 pares de cromossômios se separam normalmente. Em telófase I, os cromossômios se colorem mal. Não há, praticamente, intercinese; os cromossômios contraem-se de novo e entram em anáfase II. A formação dos micrósporos é normal. Depois de soltos, ocorre a divisão nuclear, dando origem a dois núcleos com 22 cromossômios. Isto ocorre três a quatro dias antes da abertura das flores; o núcleo vegetativo é grande, esférico e homogêneo, colo-rindo-se mal; o núcleo reprodutivo é menor, reticulado, colore-se bem e se localiza na periferia da célula; ao seu redor se destaca uma porção de citoplasma, de forma lenticular. A divisão do núcleo reprodutivo geralmente se dá no tubo polínico. Tanto o núcleo vegetativo como o reprodutivo pode ser encontrado na extremidade do tubo polínico. Poucas irregularidades foram observadas na distribuição dos cromossômios, tendo, a grande maioria dos gâmetas, n=22 cromossômios.

    Abstract in English:

    This paper presents results of cytological observations on microsporogenesis of the semperflorens and caturra varieties of the species Coffea arabica L. In general meiosis was found to be normal, the gametes having n = 22 chromosomes. Only minor irregularities were observed and these were limited to distribution of the chromosomes. In the early prophase of meiosis the chromosomes did not stain well. In the pachytene stage the chromosomes stained comparatively well and showed several hetero-piknotic regions separated by very fine sections which stained faintly. The centromere was readily seen and was located between two heteropiknotic sections. The extremities of the arms of the chromosomes stained very poorly and were lost to view in the cytoplasm. The nucleolus was easily visible and some of the chromosomes appeared to be attached to it. The exact number of chromosomes that were attached to the nucleolus appear to vary from one to four. From the pachytene stage the chromosomes passed very rapidly to metaphase I. In the diplotene stage the chromosomes were observed to be very short and the centromeres could not be seen. In the diakinesis stage the darkest colored parts of the 22 pairs of chromosomes, especially where the centromeres were located, were well separated indicating that they repelled each other. In contrast the slightly stained regions of the chromosomes were intimately associated and showed chiasmata. The number of chiasmata per cell varied from 29 to 43, the average per bivalents being 1.67 in semperflorens and 1.75 in caturra. In metaphase I the average number of chiasmata per bivalent was determinated as 1.69, in semperflorens and 1.67 in caturra. In anaphase I the 22 pairs of chromosomes were normally separated and in telophase I the chromosomes did not stain well, again making detailed observations difficult. Practically no interkinesis was observed. Following telophase I the chromosomes were observed to contract and entered into anaphase II, that was observed to be normal. The formation of microspores appeared to be normal. After separation of the microspores there occured a division of the nucleus giving origin to two nuclei with 22 chromosomes each. This was observed ot occur three to four days before opening of the flowers. The vegetative nucleus was observed to be large, round, homogeneous, and stain only faintly. The reproductive nucleus was observed to be small, reticulated ; it stained well, and was located at the periphery of the cell. The reproductive nucleus was usually found to be surrounded by a small amount of cytoplasm in a lenticular shape. The division of the reproductive nucleus usually takes place in the pollen tube. Both vegetative and reproductive nuclei were observed to occur in the extremity of pollen tube.
  • Estudo do sistema radicular do arroz

    Germek, Emílio B.; Inforzato, Romeu; Franco, Coaraci M.

    Abstract in English:

    The development of the root system on five varieties of rice grown under upland conditions, has been studied. It has been found, with the rice varieties used and under the conditions tested, that 66 percent of the roots occured within 5 centimeters and 95 percent within 15 centimeters of the surface of the ground. A few roots were found to reach a depth of 1 meter, and occasionally to a depth of 1.35 meter. The Iguape-catete variety of rice showed a tendency to develop a somewhat deeper root system than the other varieties studied. Recognition of the fact that development of the roots of the rice plant is largely within the plowed layer of soil, suggests that deep plowing prior to planting with frequent and shallow cultivation following planting, to eliminate weed competition, would be desirable.
  • O milho como planta-teste para o vírus do mosaico da cana de açúcar

    Costa, A. S.; Penteado, M. P.
  • Mosaico do pimentão

    Costa, A. S.; Alves, Sebastião
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