RESUMO
The expression of defensive compounds derived from secondary metabolism in plants of Eucalyptus globulus Labill, and the persistence of these in vegetative propagation was evaluated by gas chromatography with flame ionization (GC-FID) and mass spectrometry (MS). The plants were induced by attack from the insect Ctenarytaina eucalypti ("blue gum psyllid") and by mechanical damage. Defense responses were activated in plants for the different types of tested induction. We identified four defensive compounds present in the leaves of plants induced in entomological form (beta-terpineol, aromadendrene, caryophyllene-oxide and eremophilene); all remained in the vegetative propagation. After mechanical induction, we identified three compounds (beta-terpineol, aromadendrene and ledol), of which ledol and aromadendrene persisted in the vegetative propagation. Virtually all the compounds detected, in addition to persisting in the vegetative propagation, showed specificity for the induction type, whether entomological or mechanical, except for aromadendrene, which was expressed in both types of induction.
Assuntos
Eucalyptus/química , Azulenos/química , Cromatografia Gasosa , Eucalyptus/fisiologia , Ionização de Chama , Sesquiterpenos Policíclicos , Sesquiterpenos/químicaRESUMO
The limited development of photoprotective mechanisms, specifically heat dissipation capacity, found in micropropagated plants may be the result of low xanthophyll cycle pigment content and reduced de-epoxidation capacity making them highly susceptible to photodamage. The effects of gradual or sudden increase of light on Castanea sativa in vitro cultured and during their ex vitro transference was evaluated. The results were compared with those determined in nursery-grown plants. In vitro plants responded poorly to gradual increase in irradiance, exhibiting a low electron transport rate (ETR) agreeing with low non-photochemical quenching (NPQ) and a limited de-epoxidation capacity, not synthesizing detectable amounts of zeaxanthin (Z). Regarding a sudden increase in light (photoinhibition treatment, PhT); post-PhT as in vitro as well nursery plants showed a significant decrease in their maximal efficiency of PSII (F(v)/F(m)), but in vitro the decrease was very drastic (around 0.2) different from that observed in nursery (around 0.69). In vitro, NPQ was mainly determined by the slow relaxing component, NPQ(s) (80.8%), concomitant with a pronounced decrease of D1 protein post-PhT, and a lack of de-epoxidation capacity. During ex vitro transfer, PhT lead to death of some plants, specifically during root induction. The photoprotective mechanisms were activated over time in ex vitro conditions, indicating that micropropagated Castanea sativa display a potential for light acclimation, adjusting their photosynthetic apparatus to the ambient growth irradiance. Understanding the mechanisms that micropropagated plants deployed and how they face high light intensity events, will allow us to search for strategies to improve performance to possible light fluctuations that normally occur in ex vitro conditions during plant acclimation.
Assuntos
Aclimatação , Metabolismo Energético , Fagaceae/efeitos da radiação , Luz , Clorofila/análise , Proteínas de Cloroplastos/análise , Proteínas de Cloroplastos/química , Transporte de Elétrons , Fagaceae/química , Fagaceae/crescimento & desenvolvimento , Oxirredução , Processos Fotoquímicos/efeitos da radiação , Complexo de Proteína do Fotossistema II/química , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/efeitos da radiação , Raízes de Plantas/química , Raízes de Plantas/crescimento & desenvolvimento , Tilacoides/química , Xantofilas/química , Zeaxantinas , beta Caroteno/análise , beta Caroteno/químicaRESUMO
Quillaja saponaria (Quillay), an evergreen tree found in Chile, is one of the main sources of saponins. Quillaja saponins have hypocholesterolaemic, anticarcinogenic, antioxidant and pesticidal properties, and are used as adjuvants for vaccines. Samples of Quillay growing at three zones in O'Higgins Region, Chile (Coastal, Central and Mountain zones) were analyzed for content of saponins and physiological status. The results revealed differences in the content of saponins depending on the zone of sample collection. The highest contents were found in samples from the Mountain zone, where the highest saponin contents were accompanied by the lowest foliar nitrogen contents, the highest antioxidant activity and the highest carotenoid contents. The results suggest a physiological and adaptive mechanism of saponins in plants to survive under unfavourable environmental conditions. The results have important implications for a theoretical basis for the design of a reasonable harvest, to avoid the cost of poor quality material, and also to provide a sustainable use and conservation of this important species. Further research on the effects of stress will improve our understanding of the saponins production and their physiological functions in plants, whereas they have generally been studied for their biological and chemical applications.
Assuntos
Ecossistema , Quillaja/química , Saponinas/isolamento & purificação , Antioxidantes/análise , Plantas Medicinais/química , Plantas Medicinais/fisiologia , Quillaja/fisiologiaRESUMO
Quantification of deoxynucleosides using micellar high-performance capillary electrophoresis (HPCE) is an efficient, fast and inexpensive evaluation method of genomic DNA methylation. This approach has been demonstrated to be more sensitive and specific than other methods for the quantification of DNA methylation content. However, effective detection and quantification of 5-methyl-2'-deoxycytidine depend of the sample characteristics. Previous works have revealed that in most woody species, the quality and quantity of RNA-free DNA extracted that is suitable for analysis by means of HPCE varies among species of the same gender, among tissues taken from the same tree, and vary in the same tissue depending on the different seasons of the year. The aim of this work is to establish a quantification method of genomic DNA methylation that lends itself to use in different Castanea sativa Mill. materials, and in other angiosperm and gymnosperm woody species. Using a DNA extraction kit based in silica membrane has increased the resolutive capacity of the method. Under these conditions, it can be analyzed different organs or tissues of angiosperms and gymnosperms, regardless of their state of development. We emphasized the importance of samples free of nucleosides, although, in the contrary case, the method ensures the effective separation of deoxynucleosides and identification of 5-methyl-2'-deoxycytidine.
Assuntos
Metilação de DNA , DNA/química , Desoxicitidina/análogos & derivados , Eletroforese Capilar/métodos , Fagaceae/genética , DNA de Plantas/química , Desoxicitidina/química , Fagaceae/metabolismoRESUMO
Se estudió la inducción de callo embriogénico a partir de tres explantos provenientes de semillas maduras (embriones cigóticos maduros, hipocótilos y cotiledones). Los resultados indicaron que el medio I3 (B5 + ANA 0,5mgúl-1 + BAP 1,0mgúl¹1) produjo los mayores porcentajes de formación de callo en todos los explantes. La micromorfología evidenció presencia de células embriogénicas en todos los explantes, pero en hipocótilos y cotiledones se encontraron estados globulares en fases iniciales. Posteriormente, en la fase de diferenciación, se obtuvo como máximo 25 estados globulares por callo reactivo, en un medio B5 suplementado con maltosa (2 por ciento p/v) al utilizar embriones cigóticos maduros. El estudio histológico indicó una diferenciación interna de los estados globulares, caracterizada por una formación concéntrica de haces vasculares, células de tipo parenquimático hacia la periferia y finalmente una protodermis, formada por células isodiamétricas