RESUMEN
The aim of this work was to provide information about kinetin effects on chemical volatile profile of Curcuma zedoaria (Christm.) Roscoe after several days of plant dormancy release. Rhizomes of C. zedoaria were immersed in four kinetin concentrations (0, 50, 100, 150 mg ml-1, n = 12 by each concentration) for 30 min. After 240 h of treatment, root length (mm), bud break (%) and bud speed index (BSI) were measured, and three rhizomes at 24 h and 240 h were collected for chemical volatile profile analysis by application of headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Kinetin does not alter morphological aspects of the bud dormancy releasing, but drastically changes metabolic aspects of volatile production on C. zedoaria rhizomes, by the selection of several monoterpenes, such as camphene, sabinene, isoborneol, borneol, 1,8-cineole. We assume that kinetin application maintain monoterpene production as a consequence of its signaling over dormancy release.
Asunto(s)
Curcuma , Rizoma , Cromatografía de Gases y Espectrometría de Masas , Cinetina , Microextracción en Fase SólidaRESUMEN
This study aimed to analyse the allelopathic bioactivity of fresh and infused aqueous extracts of Brazilian cherry leaves on the germination of lettuce and the initial development of maize. Brazilian cherry leaves were used to prepare a fresh aqueous extract (200 g L-1) and an infused extract (100 g L-1), which were diluted to concentrations of 0.4, 0.8, 1.2, 1.6 or 2.0% w/v. The variables evaluated in lettuce were the germination rate (GR), germination time index (GTI), germination speed index (GSI) and root length (RL). To determine the effect on the initial development of maize, we measured the shoot (SL) and root (RL) length. The experimental design included a factorial 2 × 5 design (two extracts and five concentrations), in addition to a control treatment (no extract). In general, the allelopathic bioactivity differed between the fresh and infused extracts. The fresh extract was more phytotoxic for the GR and RL of lettuce. Some beneficial results were observed for the infused extract, including an increase in the RL of lettuce and SL of maize. These effects were dependent on the extract concentration. Thus, there is evidence that Brazilian cherry extracts have allelopathic bioactivity.
O presente trabalho tem por objetivo em analisar a bioatividade alelopática do extrato fresco e infuso de pitangueira sobre a germinação de alface e no desenvolvimento inicial de milho. Para tanto, utilizaram-se folhas frescas de pitangueira para preparação de extratos aquosos fresco (200 g L-1) e infuso (100 g L-1), diluídos em 0,4; 0,6; 1,2; 1,6 e 2,0% p/v de concentração. Os parâmetros avaliados em alface foram porcentagem (PG), tempo médio (TMG) e velocidade média de germinação (VMG) e comprimento de raiz (CR). Já no desenvolvimento inicial do milho, obteve-se o comprimento de raiz (CR) e parte aérea (CPA). Os experimentos foram conduzidos em esquema fatorial 2x5 + tratamento controle (ausência de extrato), com dois tipos de extratos e cinco concentrações. De modo geral, a bioatividade alelopática dos extratos frescos e infusos foi diferente, sendo que o extrato fresco mostrou-se fitotóxico sobre a PG e CR de alface. Alguns resultados benéficos foram observados com o extrato infuso como aumento no CR de alface e no CPA de milho. Os efeitos desses extratos dependem das concentrações onde são testados. Dessa forma, há evidência de que os extratos de pitangueira possuem bioatividade alelopática.