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| Registros recuperados: 14 | |
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| Medina,J. C.. |
| Sisal (Agave sisalana Perrine) accounts for about one half of the world's production of hard fibers. In spite os its economic importance pratically no research work has been carried out on this plant. Very little is known about the agronomic problems of its cultivation, while the physiological and genetic problems are nearly unknown. This is perhaps due to the fact that A. sisalana is a perennial plant with a life cycle of 5-8 years and the carrying out of field research work requires a great deal of time and is very expensive. This paper, the first of a series to be published on the agronomic problems of sisal cultivation, presents the data obtained from field trials on distance of planting and its relation to weight and number of leaves produced. The... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1948 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051948000100007 |
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| Medina,J. C.. |
| Sisal (Agave sisalana Perrine) growing in various localities of the State of São Paulo is often heavely damaged by "leaf basal necrose", whose symptoms are identical with the "leaf foot disease" reported from Java, East Africa and Belgian Congo. The affected leaves show in the initial stages small spots of black, slightly shrivelled tissue on the lower part of the leaf. These gradually spread out. During the later stages the affected leaves bent over at this point. Only approximately mature leaves of plants between 18 to 30 months old are affected. This disturbance was first observed in Anapolis, Araraquara and Campinas. It was thought to be due to K deficiency in the soil. In order to prove this a small fertilizer experiment was established at Campinas... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1943 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051943000400002 |
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| Medina,J. C.; Aguirre Júnior,J. M.; Correia,F. A.. |
| In spite of the polymorphism of Phormium has long been known, no systematic attempt has been made until now to study comparatively the agricultural value and fiber quality of the varieties. This paper is concerned with preliminary results about leaf yield, fiber-content, und general growth of six varieties, of Phormium tenax Forster including a detailed fiber analysis. It is concluded that the varieties have shown strong differences in plant development and fiber qualities, suggesting that some of them would be much more suitable for the improvement of existing areas, and the establishment of new ones on a commercial basis. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1947 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051947000900001 |
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| Medina,J. C.; Jensen,G. O.; Neri,J. P.. |
| A study was made of the chemical composition of samples of the ribbons taken from the rami stalks at successive stages of growth with the object of determining the percentage oí lignin, cellulose, pectin, pentosans and of some substances not belonging to the cell wall. After an initial decrease, the percentage of ash increased as the plant grew and matured. The maximum (17,5%) was reached when the plant was 105 days old. The percentage of cellulose increased regularly and reached a maximum (38,2%) when the plant was 75 days old. Subsequently there was a decrease as the plant grew older. After an initial increase, the percentage of lignin decreased somewhat and again increased as the plant matured. The maximum (14,5%), however, was observed when the plant... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1942 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051942001100001 |
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| Medina,J. C.; Correia,F. A.. |
| In this paper it is presented a detailed fiber analysis of leaves of twenty mature sisal plants taken from four positions on the plant: 1) first developped leaves (75°); 2) leaves usually cut for fiber extraction (50°) ; 3) leaves adjacent to the central bud (25°) ; and 4) young leaves not yet unfolded from the central bud (0°). The results herein reported are against the prevailing opinion that the sisal leaf only matures after it has unfolded from the central bud. Neither the physical nor the chemical fiber characteristics were adversely affected even if cutting was carried out up to the very young leaves. This practice, however, cannot yet be advised, as it desirability also depends on the effects of the severe cutting upon the subsequent rate of growth... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1947 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051947000800001 |
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| Medina,J. C.. |
| The present paper deals with the influence of different rates of spacing on the poling of sisal plants (Agave sisalana Perrine). The results were obtained from spacing trials (four randomized blocks of nine treatments) carried out at the Ribeirão Preto and Pindorama Experimental Stations. The percentages of poling plants, up to the 5th leaf cutting, were 20,0% and 91,7% for the narrowest (1,2 x 2,0 m) and widest (2,0 x 3,0 m) spacings tried in Pindorama, while in Ribeirão Preto they were 12,5% and 02,5%, respectivelly. According to these results it may be concluded that the narrow spaced plants were less liable to early poling than the wide spacing ones. The trial at Ribeirão Preto also indicated that among the plants, grown under the same conditions,... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1946 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051946000300001 |
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| Medina,J. C.. |
| O A. apresenta nêste artigo os resultados obtidos em uma experiência de corte das folhas do sisal (Agave sisalana Perrine), na qual se procurou comparar os efeitos da combinação de diversas freqüências e severidades de corte sobre o desenvolvimento, produção e longevidade da planta, assim como sôbre as características tecnológicas da fibra. Ficou provado que, com cortes freqüentes e severos, o ciclo de vida das plantas fica bastante prolongado, ao mesmo tempo que a produção de fibras por unidade de área decai sensivelmente, em conseqüência da redução de tamanho das fôlhas e menor conteúdo de fibras nas fôlhas das plantas submetidas a êsse sistema de corte. Os exames de laboratório demonstraram que, enquanto as características químicas das fibras não eram... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1954 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051954000100003 |
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| Registros recuperados: 14 | |
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