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| Registros recuperados: 218 | |
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| Jor,S. de Toledo Piza. |
| In a previous, publication (3) the author described the behaviour of the sex-chromosomes, of Dysdercus mendesi Blöte Following conversation with Dr. Luiz O. T. Mendes, the author was simulated to reexamine the, slides and to study another new series of slides" As a result of these observations the¹ writer now concludes that in the division of the 2nd spermatocytes the sex-chromosomes pass undivided to one pole. Thus half of the spermatids receives a single compound element and half receives none. This is believed to be; similar to the conclusions reached by. Dr.. Luiz O. T. Mendes. Further studies will be made with respect to the nature of the compound element. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1947 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051947000900004 |
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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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| Mendes,Antônio J. T.. |
| O tratamento de sementes de Coffea canephora (2n=22), C. Dewevrei (2n=22) e C. arabica (2n=44), por soluções de colchicina de 0,15% a 0,60% produziu plantas com número duplo de cromossômios (2n=44 em C. canephora e C. Dewevrei e 2n=88 em C. arabica). O tratamento de gemas foliares por pasta de lanolina contendo 0,10 a 0,60% de colchicina não produziu resultado nessas mesmas 3 espécies. Elaborou-se um novo método de tratamento de ramos que pode ser aplicado para os casos em que a planta que se deseja "duplicar" seja estéril. É o caso dos híbridos entre C. canephora e C. arabica (2n=33) e da forma di-haplóide (monosperma) de C. arabica (2n=22), os quais nâo produzem sementes, ou, melhor, cujas raras sementes têm em geral um embrião com número variado de... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1947 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051947000800002 |
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| Registros recuperados: 218 | |
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