RESUMO
RESUMO O gênero Aloe, originário principalmente da África, tem atualmente uma ampla distribuição no mundo. No entanto, são poucas as regiões que têm realizado estudos quanto ao sistema reprodutivo. O objetivo do presente trabalho foi analisar as características e o comportamento reprodutivo de Aloe saponaria em Florianópolis, Santa Catarina. Foram conduzidos estudos sobre sua morfologia e biologia floral, visitantes florais e sistema reprodutivo. Esta espécie apresentou uma inflorescência por planta, com um comprimento de 105 ± 0,1 cm e 267 ± 92,7 flores. A razão pólen/óvulo sugere que a espécie é xenogâmica. O volume e concentração de sólidos solúveis totais do néctar potencial foi 16,6 ± 6,3 μL e 22 ± 2,4 °Brix respectivamente. O néctar instantâneo não apresentou diferenças significativas nos períodos avaliados (9:00h e 15:00h) e o estigma permaneceu receptivo até o segundo dia após a antese. Foram coletados 110 insetos visitantes florais, dos quais 61,8% foram indivíduos de Trigona spinipes. Entretanto, nos testes de polinização não foi observada frutificação efetiva, indicando que a propagação vegetativa é o principal tipo de reprodução usado nessa população. Isto pode estar relacionado a um mecanismo de autoincompatibilidade esporofítica, a anormalidades cromossômicas durante a formação do pólen, as condições climáticas, e a escassa variabilidade genética no local de estudo.
ABSTRACT The Aloe genus, originating mainly from Africa, currently has a wide distribution in the world. However, in few regions studies about the reproductive system have been carried on. The aim e of this study was to analyze the characteristics and reproductive performance of the Aloesaponaria in Florianópolis, Santa Catarina. The morphology, floral biology, flower visitors and the reproductive system were determined. The plants presented an inflorescence per plant, with 105 ± 0,1 cm in length and 267 ± 92.7 flowers. The pollen/ovule ratio suggested that the species is xenogamic. The volume and concentration of total soluble solids in the potential nectar were 16.6 ± 6.3 μL and 22 ± 2.4°Brix, respectively. The instant nectar showed no significant differences between the evaluated periods (9:00h and 15:00h) and the stigma remained receptive until the second day the after anthesis. 110 insects were collected, from which 61.8% were from theTrigona spinipesspecies. However, in the pollination tests the fruit set was not observation, indicating that vegetative propagation is the main type of reproduction used by this population. This may be related to a mechanism of sporophytic self-incompatibility, to chromosomal abnormalities during the formation of pollen, to weather conditions, and to the low genetic variability at the study site.
Assuntos
Comportamento Reprodutivo/classificação , Aloe/classificação , Polinização , InflorescênciaRESUMO
BACKGROUND AND AIMS: The thin cell layer (TCL) technique is based on the use of very small explants and has allowed enhanced in vitro morphogenesis in several plant species. The present study evaluated the TCL technique as a procedure for somatic embryo production and plantlet regeneration of peach palm. METHODS: TCL explants from different positions in the shoot apex and leaf sheath of peach palm were cultivated in MS culture medium supplemented with 0-600 microM Picloram in the presence of activated charcoal. The production of primary calli and embryogenic calli was evaluated in these different conditions. Histological and amplified fragment length polymorphism (AFLP) analyses were conducted to study in vitro morphogenetic responses and genetic stability, respectively, of the regenerated plantlets. KEY RESULTS: Abundant primary callus induction was observed from TCLs of the shoot meristem in culture media supplemented with 150-600 microM Picloram (83-97%, respectively). The production of embryogenic calli depends on Picloram concentration and explant position. The best response observed was 43% embryogenic callus production from shoot meristem TCL on 300 microM Picloram. In maturation conditions, 34+/-4 somatic embryos per embryogenic callus were obtained, and 45.0+/-3.4% of these fully developed somatic embryos were converted, resulting in plantlets ready for acclimatization, of which 80% survived. Histological studies revealed that the first cellular division events occurred in cells adjacent to vascular tissue, resulting in primary calli, whose growth was ensured by a meristematic zone. A multicellular origin of the resulting somatic embryos arising from the meristematic zone is suggested. During maturation, histological analyses revealed bipolarization of the somatic embryos, as well as the development of new somatic embryos. AFLP analyses revealed that 92% of the regenerated plantlets were true to type. The use of TCL explants considerably improves the number of calli and somatic embryos produced in comparison with previously described protocols for in vitro regeneration of peach palm. CONCLUSIONS: The present study suggests that the TCL somatic embryogenesis protocol developed is feasible, although it still requires further optimization for in vitro multiplication of peach palm, especially the use of similar explants obtained from adult palm trees.
Assuntos
Arecaceae/embriologia , Clonagem de Organismos/métodos , Desenvolvimento Embrionário/fisiologia , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Arecaceae/citologia , Arecaceae/genética , Desenvolvimento Embrionário/efeitos dos fármacos , Meristema/citologia , Meristema/embriologia , Meristema/genética , Picloram/administração & dosagem , Picloram/farmacologia , Brotos de Planta/citologia , Brotos de Planta/embriologia , Brotos de Planta/genéticaRESUMO
The potential risks of GMOs, their impact on human and animal health, and on the environment, as well as their socioeconomic effects, have generated a worldwide discussion which is far from drawing to a close for lack of sufficient information. Part of this information supports risk-hypotheses previously put forward. Thus the presence of transgenic plant genes in other plants and in other organisms has been confirmed in several occasions. Therefore, gene dissemination to plants of the same species as well as to widely different species is already regarded as an actual risk. The principle of substantial equivalence has opened the way for the liberation of transgenic plants for commercial crops, despite short-term tests, which are quantitatively and qualitatively insufficient to certify that the foods deriving from those plants are healthy and safe. Thus, the adoption of the so-called precautionary principle (PP) has turned out to be the most adequate safety measure to date, or else until scientific data should be able to demonstrate the actual impact of transgenic plants on human and animal health, and on the environment.
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Plantas Geneticamente Modificadas , Risco , Agricultura/métodos , Agricultura/tendências , Indústria Alimentícia/história , Indústria Alimentícia/métodos , Indústria Alimentícia/tendências , História do Século XX , Plantas Geneticamente Modificadas/efeitos adversosRESUMO
PIP: 70% of AIDS victims are homosexuals and 20% are iv drug abusers. In Spain and Italy more than 50% of AIDS victims are drug abusers. According to the work group on AIDS in Portugal in January 1990 there were 348 cases diagnosed: 159 were homosexuals and bisexuals, 36 were drug addicts, 74 were heterosexuals, 19 were hemophiliacs, 17 had had blood transfusions, 1 was a mother-child infection, and 42 were unknown routes of infection. The typical profile of a drug addict includes a low threshold of frustration, irresponsibility, lack of remorse, and inability to follow a life plan. The work group on AIDS and WHO proposed the use of sterile syringes and condoms for drug addicts, however, practical implementation is difficult. A 1989 study in Buenos Aires showed that about 34% of drug addicts became HIV seropositive via the iv route. A 1989 prison population study indicated that 61% of 113 imprisoned drug addicts were seropositive. Preventive behavior modification is difficult to achieve in an isolated way. A global intervention strategy is needed for AIDS prevention involving all professionals combating its spread in order to break the cycle of self-destruction and aggression of drug addicts who are ostracized, rejected, and punished by society.^ieng
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Síndrome da Imunodeficiência Adquirida , Infecções por HIV , Homossexualidade , Prisioneiros , Transtornos Relacionados ao Uso de Substâncias , América , Argentina , Comportamento , Países Desenvolvidos , Países em Desenvolvimento , Doença , Europa (Continente) , Itália , América Latina , Comportamento Sexual , Problemas Sociais , América do Sul , Espanha , VirosesRESUMO
The induction of somatic embryogenesis in embryo cultures of Euterpe edulis is described. The basal medium was composed of LS salts and Morel & Wetmore vitamins. Activated charcoal was added to prevent explant oxidation. 2,4-D higher than 50 mg/l was necessary for inducing embryogenesis which occurs 45-180 days after the start of cultures. Embryos arise directly from surface proliferating tissues on the matrix structure , without callus formation. The transfer of tissues with embryo clusters to medium with NAA plus 2iP, or without growth regulators, induces embryo development into plantlets.
RESUMO
Leaf, stem and root explants of Mandevilla velutina were cultured in vitro and produced vigorous callus in LS basal medium containing one auxin (2,4-D or NAA) plus BAP. Calli can be subcultured indefinitely with vigorous growth. Subculture of calli to NAA (1.0 mg/l) plus BAP (5.0 mg/l) caused profuse regeneration of shoots. Isolated shoots were rooted in basal medium plus NAA (5.0 mg/l) or IBA (8.0 mg/l). Rapidly growing cell suspensions can be easily obtained from friable callus cultured in liquid medium.