Comparative Study of Metabolomic Profile and Antioxidant Content of Adult and In Vitro Leaves of Aristotelia chilensis.

This work aimed to identify the bioactive compounds present in adult maqui (Aristotelia chilensis) leaves from different stages of development and seasons of the year and compare them with leaves obtained from maqui plants grown in vitro. The qualitative and quantitative analysis of maqui leaf extracts by HPLC-DAD-ESI-MSn showed the presence of different polyphenolic compounds classified into galloyl and caffeoyl quinic acids, ellagitannins and ellagic acid- and flavonoid-derivatives. In general, the total phenolic content of the in vitro samples was higher than that of ex vitro samples, whereas the total flavonoid content was higher in winter basal leaves. Additionally, the analysis by HPLC-MS showed that the extract from spring basal leaves was enriched in quercetin, catechin, kaempferol and 3-caffeoyl quinic acids, while in the in vitro leaves extract, quercetin was not present. As regards lipophilic compounds identified by GC/MS, the samples of in vitro leaves showed a high presence of α-tocopherol and ß-sitosterol. In contrast, the samples of adult leaves presented a hight level of linolenic and linoleic acids. These results suggest that maqui leaves could be an excellent source of antioxidants and lipophilic compounds for many industries, such as the nutraceutical and pharmaceutical industries.

Induction of defensive response in Eucalyptus globulus plants and its persistence in vegetative propagation.

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.

Light energy management in micropropagated plants of Castanea sativa, effects of photoinhibition.

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.

Reactivación de material vegetal élite de Pinus radiata D. Don. mediante microinjerto in vitro / Reactivation of elite Pinus radiata D. Don. plant tissue by in vitro micrografting

Se evaluaron dos protocolos de asepsia, tipos de púa (yemas y braquiblastos), épocas de recolección (otoño y verano) y posición de la púa (apical y basal) en el ortet, sobre el establecimiento y consolidación de microinjertos de Pinus radiata D. Don. Las púas se obtuvieron de clones adultos cultivados en vivero. Las asepsias consistieron en la inmersión en hipoclorito de sodio 2,5 por ciento v/v i.a, durante 15min (A1); o por 20min, seguido de la inmersión en una solución de benomyl+cisteína 50mg·l-1 c/u, hasta su utilización (A2). Como patrón se utilizaron hipocótilos provenientes de semillas germinadas in vitro en medio QL sin reguladores de crecimiento. Se realizaron microinjertos según la técnica apical de cuña. Estos se mantuvieron en tubos con medio QL + 0,1 mg·l-1 AIB y 1mg·l-1 BAP, a 25 ±2°C, intensidad lumínica de 80µmol·m-2·s-1 y fotoperíodo de 16h. Se utilizó un diseño completamente al azar en arreglo factorial (24), con 13 repeticiones. El establecimiento mostró diferencias significativas entre las interacciones tipo de asepsia/época del año y tipo de púa/época del año, resultando ser las yemas apicales recolectadas durante el otoño y la asepsia tipo A2, los mejores tratamientos para el establecimiento de los microinjertos de P. radiata. La consolidación estuvo influenciada por el tipo de púa y la época del año en que se realizaron los microinjertos, siendo nuevamente la yema apical (YA) el material más reactivo.

Inducción de callo embriogénico en eucalyptus globulus labill / Embryogenic callus induction in eucalyptus globulus labill

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