Persistência de plantas medicinais em sistemas agroflorestais no município de São Bento do Sul, SC, Brasil / Persistence of medicinal plants in agroforestry systems in the city of São Bento do Sul, Santa Catarina, Brazil

No final da década de 90, a comunidade de Rio Natal, no município de São Bento do Sul, SC, passou a fazer parte de uma Área de Preservação Ambiental e desde então, muitas áreas de cultivo, paulatinamente, estão retomando o processo de formação florestal. Neste cenário, foi sugerido pela comunidade, a possibilidade de cultivo de plantas medicinais adaptadas às condições de sombreamento. Em atendimento a essa demanda foi realizada uma pesquisa participativa na comunidade, de 2005 a 2008, onde foram avaliadas 14 espécies de plantas medicinais com potencial de mercado, cultivadas em áreas sombreadas, em três propriedades familiares. Foram avaliados: taxa de sobrevivência das espécies, incidência de doenças e pragas, teor de massa seca e altura das plantas. Apresentaram persistência ao cultivo em áreas sombreadas as espécies: Curcuma longa L. (açafrão-da-índia); Arctium lappa L. (bardana); Pfaffia glomerata (Spreng) Pedersen (fáfia ou ginseng-brasileiro); Mikania glomerata Sprengel (guaco); Alternanthera brasiliana L. Kuntze (penicilina); Pogostemon cablin (Blanco) Benth (patchuli) e Maytenus ilicifolia Mart. Ex Reissek (espinheira-santa).

In the end of the 1990s, the Rio Natal community, located in the city of São Bento do Sul, in the Brazilian State of Santa Catarina, started to be part of an Environmental Protection Area. Since then, many cultivation areas have been increasingly having their forest restored. In this scenario, the community proposed to cultivate medicinal plants that were adapted to shaded conditions. To attend this demand, we carried out a participatory research in the community between 2005 and 2008. Fourteen species of medicinal plants having market potential were evaluated, and were cultivated in shaded areas, in three family properties. The survival of the species, the incidence of illnesses and pests, the dry matter value and the height of the plants were evaluated. The species that presented persistence to be cultivated in shaded areas were: Curcuma longa L.; Arctium lappa L.; Pfaffia glomerata (Spreng) Pedersen.; Mikania glomerata Sprengel.; Alternanthera sp.; Pogostemon cablin (Blanco) Benth. e Maytenus ilicifolia Mart. Ex Reissek.

A pulsed electron gun for ultrafast electron diffraction at surfaces.

The construction of a pulsed electron gun for ultrafast reflection high-energy electron diffraction experiments at surfaces is reported. Special emphasis is placed on the characterization of the electron source: a photocathode, consisting of a 10 nm thin Au film deposited onto a sapphire substrate. Electron pulses are generated by the illumination of the film with ultraviolet laser pulses of femtosecond duration. The photoelectrons are emitted homogeneously across the photocathode with an energy distribution of 0.1 eV width. After leaving the Au film, the electrons are accelerated to kinetic energies of up to 15 keV. Focusing is accomplished by an electrostatic lens. The temporal resolution of the experiment is determined by the probing time of the electrons traveling across the surface which is about 30 ps. However, the duration of the electron pulses can be reduced to less than 6 ps.