Economic versus technical efficiency in using ASM combined with fungicides to elicit wheat varieties with different disease susceptibilities.

Despite the positive results of using elicitors to induce resistance against plant diseases, some factors have inhibited the popularization of their use in agriculture. There is an energetic cost related to the elicitors' induced response which can cause undesired effects on growth under low-pressure disease conditions. Elicitors can create phytotoxicity and show high variation in their efficiency between different genotypes within the same crop; in addition, the positive results related to the induced resistance may not repeat in field treatments, adding to the possibility that they are not economically viable. Thus, we carried out two experiments to investigate the technical and economic efficiency of acibenzolar-S-methyl (ASM) and its association with fungicides in the control of leaf diseases of susceptible and resistant wheat varieties, and as how it reflects on the photosynthetic and production performance of wheat. This study showed the limitations of incorporating ASM into foliar fungal disease control in economic terms. However, it was evident that ASM effectively induced plant resistance against Leaf Rust and Powdery Mildew in the field and can be considered a sustainable option for wheat cultivation. Even though its association with chemical control was not the best economic strategy the use of ASM is a tool that can be incorporated into wheat cultivation to minimize the emergence of fungicide-resistant pathogens due to the diversification of modes of action employed and reduce the toxic residue deposition to the environment and human health.

Infection by Moniliophthora perniciosa reprograms tomato Micro-Tom physiology, establishes a sink, and increases secondary cell wall synthesis.

Witches' broom disease of cacao is caused by the pathogenic fungus Moniliophthora perniciosa. By using tomato (Solanum lycopersicum) cultivar Micro-Tom (MT) as a model system, we investigated the physiological and metabolic consequences of M. perniciosa infection to determine whether symptoms result from sink establishment during infection. Infection of MT by M. perniciosa caused reductions in root biomass and fruit yield, a decrease in leaf gas exchange, and down-regulation of photosynthesis-related genes. The total leaf area and water potential decreased, while ABA levels, water conductance/conductivity, and ABA-related gene expression increased. Genes related to sugar metabolism and those involved in secondary cell wall deposition were up-regulated upon infection, and the concentrations of sugars, fumarate, and amino acids increased. 14C-glucose was mobilized towards infected MT stems, but not in inoculated stems of the MT line overexpressing CYTOKININ OXIDASE-2 (35S::AtCKX2), suggesting a role for cytokinin in establishing a sugar sink. The up-regulation of genes involved in cell wall deposition and phenylpropanoid metabolism in infected MT, but not in 35S::AtCKX2 plants, suggests establishment of a cytokinin-mediated sink that promotes tissue overgrowth with an increase in lignin. Possibly, M. perniciosa could benefit from the accumulation of secondary cell walls during its saprotrophic phase of infection.

Equipment and protocol for measurement of extracellular electrical signals, gas exchange and turgor pressure in plants.

We present a detailed protocol for measuring extracellular electrical signals in plants using the electrode insertion technique. Using this approach, it is possible to measure long-distance electrical signaling induced by several stimuli, including wounding, current application, irrigation, burning, and others. Additionally, we describe how to associate gas exchange measurements using an infra-red gas analyzer (IRGA, Model Li-6400, Li-Cor) and turgor pressure measurements using a patch clamp pressure probe (ZIM-probe, YARA ZIM-plant Technology) to measure extracellular electrical signals. • The method requires a complete electrical circuit that includes a measuring device (amplifier and voltmeter) and electrodes that provide a contact between the biological material and the equipment. • The infra-red gas analyzer (IRGA), needs to be grounded because it is an important source of noise for electrophysiological measurements. • The ZIM-probe did not cause any interference in electrical signal measure. • Our approach is useful for plant physiologists wishing to implement the technique of measuring electrical signals in plants, in association with other parameters of plant physiology. In addition, our text was written for agricultural and biological scientists who are not electronics specialists.

Medicinal plants used by "Passo da Ilha" rural community in the city of Pato Branco, southern Brazil

The scope of this work was to rescue and document the traditional knowledge regarding the medicinal plants used by Passo da Ilha rural community, in Pato Branco, Paraná State, Southern Brazil (26° 11' S, 52°36' W and 760 m high). Structured interviews were made in field research with 16 informants who had the traditional knowledge about medicinal plants. The research was carried out from October to December 2000. The plants were collected in the field, identified and their vouchers were housed at the Herbarium "Irina Delanova De Gemtchjnicov" (BOTU) of São Paulo State University, in Botucatu. A total of 47 botanical families and 114 species of medicinal plants were identified. These plants ere suitable for ore than 30 different edicinal uses. The residents are mainly of European descent, which justify the presence of many exotic plants. The knowledge on how to use medicinal plants properly is held mainly by the females, and decreases in the newer generations, denoting "cultural erosion" in progress.

O objetivo deste trabalho foi resgatar e documentar o conhecimento popular referente às plantas medicinais utilizadas na comunidade rural do Passo da Ilha, em Pato Branco-PR (26° 11' S, 52°36' W e 760 m de altitude). Optou-se por utilizar o modelo de entrevista estruturada com 16 informantes, os quais possuíam o conhecimento sobre o uso das plantas medicinais em suas famílias. O período da realização das entrevistas foi de outubro a dezembro de 2000. As plantas foram coletadas no campo, identificadas e "vouchers" foram depositados no Herbário "Irina Delanova De Gemtchjnicov" (BOTU) da Universidade Estadual Paulista, em Botucatu-SP. Foram identificadas 47 famílias botânicas e 114 espécies de plantas medicinais. Estas plantas foram indicadas para mais de 30 usos medicinais diferentes. A comunidade é composta na maioria por descendentes de europeus, justificando a presença de muitas plantas exóticas. O domínio do uso das plantas é feminino, porém o conhecimento é menor nas gerações mais novas, denotando um processo de erosão cultural.

Medicinal plants used by 'Passo da Ilha' rural community in the city of Pato Branco, southern Brazil.

The scope of this work was to rescue and document the traditional knowledge regarding the medicinal plants used by Passo da Ilha rural community, in Pato Branco, Paraná State, Southern Brazil (26 degrees 11' S, 52 degrees 36' W and 760 m high). Structured interviews were made in field research with 16 informants who had the traditional knowledge about medicinal plants. The research was carried out from October to December 2000. The plants were collected in the field, identified and their vouchers were housed at the Herbarium 'Irina Delanova De Gemtchjnicov' (BOTU) of São Paulo State University, in Botucatu. A total of 47 botanical families and 114 species of medicinal plants were identified. These plants ere suitable for ore than 30 different edicinal uses. The residents are mainly of European descent, which justify the presence of many exotic plants. The knowledge on how to use medicinal plants properly is held mainly by the females, and decreases in the newer generations, denoting 'cultural erosion' in progress.