Inhibition of ethylene response by 1-methylcyclopropene in potted ornamental pepper / Inibição das respostas ao etileno por 1-methylcyclopropeno em pimenta ornamental de vaso

In the face of great potential of 1-MCP in blocking ethylene action, this study aimed to evaluate the efficacy of 1-MCP on ethylene action and extend the post-production of ornamental peppers Capsicum annuum potted plants. Ornamental pepper cultivar Calypso shows complete abscission of leaves when exposed to 10µL L-1 ethylene. By exposing plants to ethylene, significant drops on a, b and total chlorophyll were found at the end of the treatment. Nevertheless, no changes on leaf total carotenoid were observed after the treatment with ethylene. When the plants were treated with 1-methylcyclopropene (1-MCP), followed or not by treatment with ethylene, contents of a, b, total chlorophyll and carotenoid remained unchanged. Control plants showed no changes in chlorophylls or carotenoid contents after 48 hours from moving the pots from greenhouse to indoor conditions illuminated with white fluorescent light. The 1-MCP was able to prolong the post production shelf life, by inhibiting the abscission of leaves. Plants treated with 1-MCP, followed by ethylene had 38% accumulated leaf abscission, after 18 days of post production life, similar to control plants. After the same period, plants treated only with 1-MCP had 22% leaf abscission. The 1-MCP partially blocked ethylene and induced leaf abscission. Regardless which treatment was applied during post production life, there was a continuous decrease on leaf chlorophyll content beyond 18th day. Thus, 1-MCP was effective in preventing leaf abscission even in the presence of ethylene, avoiding deleterious effects of ethylene by blocking its receptor sites.(AU)

Em face do grande potencial de utilização do 1-MCP no bloqueio da ação do etileno, este trabalho teve como objetivo avaliar a eficiência do 1-MCP em bloquear a ação do etileno e estender a vida pós-produção de plantas de pimenta ornamental da espécie Capsicum annuum. A pimenta ornamental, cultivar Calypso, apresenta abscisão completa das folhas quando exposta a 10µL L-1 de etileno. Nas plantas expostas ao etileno, houve reduções significativas dos teores de clorofila a, b e total ao final do tratamento. Nenhuma alteração no conteúdo de carotenoides total das folhas foi observada após o tratamento com etileno. Quando as plantas foram tratadas com 1-metilciclopropeno (1-MCP), seguido ou não pelo tratamento com etileno, os teores de clorofila a, b, total e carotenoides permaneceram inalterados. As plantas controle não apresentaram alterações nas clorofilas ou carotenoides, após 48 horas da remoção dos vasos da estufa para recinto fechado iluminado com luz branca fluorescente. O 1-MCP foi capaz de prolongar a vida de prateleira semelhante às plantas controle. No mesmo período, plantas tratadas somente com 1-MCP tiveram 22% de abscisão foliar. O tratamento com 1-MCP bloqueou parcialmente a queda das folhas induzida por etileno. Independentemente do tratamento aplicado, houve diminuição contínua do teor de clorofila das folhas após o 18º dia. A fumigação com 1-MCP foi eficaz na pós-produção, inibindo a abscisão das folhas. Plantas tratadas com 1-MCP, seguido por etileno, tiveram 38% de abscisão foliar acumulada, após 18 dias de vida em pós-produção, prevenção da queda de folhas, mesmo na presença de etileno, evitando os efeitos deletérios de etileno, através do bloqueio dos sítios receptores de etileno.(AU)

AgNO3: a potential regulator of ethylene activity and plant growth modulator

The aim of this review is to critically analyze the role of silver nitrate (AgNO3) in modulating plant growth and development. In recent years, basic studies on ethylene regulation opened new vistas for applied research in the area of micro-propagation, somatic embryogenesis, in vitro flowering, growth promotion, fruit ripening, and sex expression. Silver nitrate has proved to be a very potent inhibitor of ethylene action and is widely used in plant tissue culture. Few properties of silver nitrate such as easy availability, solubility in water, specificity and stability make it very useful for various applications in exploiting plant growth regulation and morphogenesis in vivo and in vitro. Silver ion mediated responses seem to be involved in polyamines, ethylene- and calcium- mediated pathways, and play a crucial role in regulating physiological process including morphogenesis. The molecular basis for regulation of morphogenesis under the influence of silver nitrate is completely lacking. This review compiles published reports of silver nitrate-mediated in vitro and in vivo studies and focuses on fundamental and applied aspects of plant growth modulation under the influence of silver nitrate.