Efeitos de terpenoides sobre a germinação, crescimento inicial, fotossíntese, fliorescência e microscopia de Glycine max, Ipomoea grandifolia e Euphorbia heterophylla

• Autor(a) principal: Reis, Bruno
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1133
• topic: Alelopatia; Fisiologia vegetal; Fotossíntese; Germinação; Crescimento; Bioherbicida; Monoterpeno; Citronelol; Citronelal; Geraniol; Mitocrondrias x Microscopia; Brasil.; Essential oil; Citronellal; Citronellol; Geraniol; Cymbopogon winterianus; Eucalyptus cinerea; Allelopathy; Bioherbicide; Brazil.; Ciências Agrárias; Agronomia

The goal of this study was to verify the bioherbicide activity of Cymbopogon winterianus essential oil, Eucalyptus cinerea essential oil, citronellal, geraniol and citronellol on germination, growth, biomass and early post-emergence of Euphorbia heterophylla, Ipomoea grandyblia control, and Glicine max . The seeds were placed in petri dishes and pots and submitted to different concentrations of C. winteriunus essential oil, E. cinerea essential oil, citronellol, geraniol and citronellal, and mixtures thereof (0 to 6%, 1.5 to 2% DMSO v/v). The petri dishes were placed in BOD at 25°C for 7 days and 12 hours photoperiod. The experiments in vases were conducted in greenhouse. For the evaluation of the gaseous exchange and fluorescence, two plants of E. heterophylla in pots (1.5 L) were sprayed with 10 mL per pot of the following treatments: citronellal, citronellol and geraniol in concentrations from 0_l to 0.6% (v/v) and water and DMSO (2% v/v) used as controls. The terpenes were diluted in 2% DMSO (v/V). For the experiments fluorescence microscopy and transmission electron microscopy (TEM) fifty seeds were placed in Petri dishes containing 10 mL of following treatments: control consisting of DMSO 20000 μL L-1, citronellal 1000 μL L-1, citronellol 350 μL L-1, geraniol 450 μL L-1, essential oil of citronella 1800 μL L-1 and essential oil of EUCGU/PTUS cinerea 4400 μL L-1. The plates were placed in BOD germination chamber with photoperiod of 12 hours and temperature set to 25°C. We determined the following variables: DL50 (median lethal dose), germination percentage (PGER), average germination time (VMV), average germination speed (VMG), germination speed index (IVG), shoot length (CPA), root system length (CSR), total length (CT), ratio of shoot length/root length (RPA/SR), shoot fresh mass (MFPA), root fresh mass (MFSR), total fresh mass (MFT), shoot dry mass (MSPA), root dry mass (MSSR), total dry mass (TDM), water content of the shoot (CAPA), water content of the root (CAR), content Total water (CAT), percentage of live plants (PVlVAS%), percentage of control (CONTROL%), percentage of viable plants (% PVIAVEIS), CO2 net assimilation (A), stomatal conductance (gs), transpiration (E) and intercellular CO2 concentration (Ci), instantaneous CO2 assimilation (A/C), intrinsic efficiency of water use (A/gs), water use efficiency (A/E) ratio sweating/stomatal conductance (E/gs), minimal fluorescence (Fo), maximal fluorescence (Fm), potential quantum efficiency of photosystem Il (FV/Fm), minimum fluorescence in a state adapted to light (Fo'), maximum fluorescence in a state adapted to light (Fm'), effective quantum efficiency of PSll (Yield). Data were submitted to ANOVA and quantitative variables analyzed by polynomial regression and Scott-Knott test at 5% probability. All variables were significantly affected with increasing treatments doses. Variables were affected germination with increasing doses of the treatments as well as biometric variables. Observed antagonistic effect between citronellal and geraniol in mixture over the germination variables. The accumulation of fresh and dry biomass was reduced with increasing doses of the treatments. In greenhouse the treatments were sprayed in early post-emergence, dose escalation of citronellol caused leaf chlorosis and necrosis in E. heterophylla, significantly affecting %PIVAS, %PVIAEIS and %CONTROL. In general, terpenes significantly affected all variables, inhibiting the germination, growth and biomass accumulation of weeds in post-emergence in pot, gas exchange variables, drastically reducing CO2 net assimilation, fluorescence and indicating cell damage and mitochondrial changes. Thus, the C. winterianus essential oil, E. cinerea essential oil and the monoterpenes citronellal, geraniol and citronellol have great potential to be used as bioherbicide. However, there is need for more detailed in metabolic level and field level so that definitive conclusions can be obtained from studies.