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 β-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.

El éxito de programas de restauración por medio del establecimiento de una cubierta vegetal en áreas que han sido alteradas, se relaciona directamente con atributos morfo-fisiológicos de las plantas que se establecen en condiciones de campo. Estos atributos han sido estudiados principalmente para diversas especies forestales a nivel nacional e internacional, no obstante, para especies nativas la investigación aun es incipiente. El objetivo de este estudio es determinar el efecto de diferentes concentraciones de fósforo y calcio en la etapa de endurecimiento en vivero, sobre atributos morfológicos (longitud de tallo, diámetro de cuello, área foliar), fisiológicos (estatus nutricional) y potencial de crecimiento radical (largo y número de raíces nuevas) de plantas de olivillo (Aextoxicon punctatum) producidas a raíz cubierta. Se definieron nueve esquemas nutricionales que variaron fósforo y calcio en tres concentraciones cada uno (0, 150 y 300 mg L-1). Luego de 13 semanas, periodo de endurecimiento, no se observaron diferencias significativas entre los tratamientos para las variables morfológicas y de potencial de crecimiento raíces. Sin embargo, tratamientos con aplicaciones de 300 mg L-1 de fósforo generaron las mayores concentraciones a nivel foliar de nitrógeno y las menores de calcio. Dosis de 300 mg L-1 de calcio aplicadas en el medio determinaron una mayor concentración foliar del mismo elemento, y un mayor número de raíces y más largas.

The success of restoration programs through the establishment of a vegetable cover on altered areas is directly related to morpho-physiological attributes of plants established on field conditions. These attributes have been mainly studied on many species at national and international level, while research on native species is still incipient. The objective of this research is to determine the effect of different concentrations of phosphorous and calcium during nursery hardening stage, on morphological attributes (stem length, stem diameter, leaf area), physiological (nutritional status) and root growth potential (number and length of new roots) in olivillo (Aextoxicon punctatum) plants produced by covered root. Nine fertilization schemes were designed with three different concentrations of phosphorous and calcium each (0, 150 and 300 mg L-1). After 13 weeks, corresponding to the hardening period, no significant differences were observed among treatments for morphological variables. However, treatments with applications of 300 mg L-1 of phosphorous induced higher nitrogen and lower calcium foliar concentrations. Higher calcium concentrations (300 mg L-1) induced higher foliar concentrations of this element and higher number and length of new roots.

Nothofagus species behave like early successional species that recolonize open sites after of regular and large-scale disturbances. This study analyzed the effects of light regimes on patterns of advanced regeneration dynamics, growth in diameter and height of Nothofagus dombeyi (Mirb.) Oerst. (Density of 240 trees ha(-1), basal area of 56.7 m(2) ha(-1)). Systematic sampling every 50 m in three stands (7.5 ha) was used. At each point and with the same center, two concentric circular plots were established, 9.0 m and 1.8 m radius. For estimate solar radiation transmissivity in plots, a solariscope hemispheric photographic camera was used. Diameters at breast height and basal areas (BA), heights (H) were measured and then counted and measured N. dombeyi seedlings and saplings. 13 saplings of advanced regeneration were harvested from all gaps to obtain age (E), total height (TH), absolute radial growth (ARG), and absolute height growth (AHG). As results, solar radiation varied between 3 and 40%. ARG varied between 1.20 and 2.22 mm yr(-1) and AHG between 0.15 and 0.43 m yr(-1). We found correlation for ARG and AHG with direct and global solar radiation transmissivity, but not with diffuse solar radiation transmissivity. The plant age and transmittance of direct and global solar radiation explains the increases in diameter and height. However, in our study stated that in the Andean region of south-central Chile, N. dombeyi stands is affected by small-scale disturbances. Therefore, transmissivity radiation solar inside the forest, explaining natural regeneration patterns and growth of N. dombeyi.

Several studies have quantified the responses of Eucalyptus globulus Labill. plantations to weed control on its early development (2–3 years after establishment). However, long-term results of competing vegetation effects have not been included into growth and yield models that incorporate treatments of competing vegetation control, and its interaction with site resource availability. In this article, we compared several models predicting stand volume yield of E. globulus plantations established across an environmental gradient, growing under different intensity levels of competing vegetation control. Four sites were selected encompassing a gradient in rainfall and amount of competing vegetation. Treatments were applied at stand establishment and were monitored periodically until age 9 years. Competing vegetation control intensity levels considered 0, 5, 20, 44, and 100% weed-free cover around individual E. globulus cuttings. Maximum competing vegetation biomass production during the first growing season were 2.9, 6.5, 2.2, and 12.9 Mg ha−1, for sites ranging from low to high annual rainfall. As expected, reductions in volume yield at age 9 years were observed as competing vegetation control intensity decreased during the first growing season. A strong relationship was established between stem volume yield loss and the intensity of competing vegetation control, the amount of competing vegetation biomass produced during the first growing season and mean annual rainfall. The slope of the relationship was different among sites and was related mainly to water and light limitations. Our results suggest that the biomass of competing vegetation (intensity of competition), affecting site resource availability, contribute to observed long-term effects on E. globulus plantations productivity. The site with the lowest mean annual rainfall showed the highest volume yield loss at age 9 years. Sites with highest rainfall showed contrasting results related to the amount of competing vegetation biomass.

Quillaja saponaria es una especie arbórea endémica de cuatro países de América del Sur. De su corteza, se extraen saponinas, moléculas de importancia económica utilizadas con fines farmacéuticos, industriales y agronómicos. En el presente estudio se evaluó el efecto de componentes hormonales sobre la capacidad morfogénica de Q. saponaria, a partir de segmentos caulinares provenientes de árboles adultos. Se empleó el medio de cultivo Murashige y Skoog (MS) suplementado con nueve concentraciones de ácido indol 3-butírico (AIB) y 6-bencilaminopurina (BAP). Se utilizó un diseño completamente al azar balanceado con cinco repeticiones; la unidad experimental fue un frasco de vidrio con cuatro explantes. El material se mantuvo en una cámara de crecimiento a 25±1 °C en el día y 22±1 °C en la noche, a una intensidad lumínica de 3000 lux y una humedad relativa de 60 %. Se determinaron efectos significativos (P = 0.01) de los tratamientos sobre las variables número de brotes y elongación caulinar. La prueba estadística de rangos múltiples de Duncan ratificó que los tratamientos con diferencias significativas fueron 1.0 mgL-1 de AIB y 2.0 mgL-1 de BAP, para número de brotes por explante y 1.5 mg L-1 de AIB y 0.5 mg L-1 de BAP para la elongación caulinar. El análisis histológico evidenció la proliferación de estructuras meristemáticas a partir de tejido subepidérmico. Estos resultados respaldan los cimientos científicos de la competencia morfogénica de árboles adultos como fuentes de germoplasma para la propagación clonal, clave en un programa de masificación de individuos elite.

A comparative study of in vitro growth of three species of ectomycorrhizal fungi (ECMF) (Rhizopogon luteolus, Suillus granulatus and Suillus luteus) was performed. Fungal material was collected in adult Pinus radiata plantations. Isolation and purification of the strains were performed on potato-dextrose-agar medium and the evaluation of the radial growth rate and the increase in mycelial biomass, under different culture conditions, was performed on the Modified Melin Norkrans growth medium. The effects of temperature (24, 28 and 32 ºC) and pH (4.8, 5.3, 5.8, 6.3 and 6.8) of the growth medium were tested for the three fungal species in two independent assays. The results indicate that the temperature had a significant effect on the radial growth rate (RG) and mycelial biomass increase (MB) in all of the evaluated fungal species. The highest RGR and MBI were recorded in R. luteolus, and the lowest values for these variables were registered in S. luteus. Rhizopogon luteolus had the highest sensitivity to pH changes. Meanwhile, there was no pattern in S. granulatus and S. luteus growth response under different pH conditions. When cultivated in vitro, the three studied species of ECMF presented adaptation, exponential, declining and stationary growth phases. The in vitro growth responses recorded in the present study showed the great potential of R. luteolus to be used in future programs using mycorrhizal inoculation in the production of Pinus radiata trees in nurseries in Chile.

Castanea sativa Mill. is a specie of agroforestry interest widely grown in Europe, its current production it is mainly focused on the extraction of a quality brown fruit, highly demanded in the gourmet industry. In Chile, this specie might be successfully grown due to the climate and lack of diseases that may affect it. However, there is not a propagation system that can provide a plant massification for the establishment of fruit orchards. Given this situation, the micropropagation is a possible alternative to apply since this method is extensively studied in this species. The propagation in vitro of Castanea sativa has created successful results in terms of introduction and multiplication. Nevertheless, the propagation in vitro of direct-producer varieties of brown fruit is still poorly studied and for this situation, in order to stablish a production system of a variety of plants of great interest is necessary to evaluate the effects of some variables that affects the in vitro culture of woody as it is the genotype and cytokine source. For this, six varieties of chestnut from Italy and France and two types of cytokines were studied to evaluate their effects on the parameters in vitro establishment as survival, contamination, formation of basal callus, axillary bud break, etc. The results indicate that in the same culture conditions the varieties with better response is Marrone Citta di Castello (CC) and Marrone Chiusa di Pesio (CP), in relation to the formation of basal callus and morphological reaction capacity, where the percentage of explants was greater than 80% and 85%, respectively, independent of the type of cytokinin used. Moreover, the amount of explants with axillary bud break was higher in the treatment with 0.5 mg L-1 of 6-benzylaminopurine (BAP) with 100% in CC and 55% in CP, being there significant differences with the obtained response in the treatment with 0.5 mg L-1 of Thidiazuron (TDZ), where 10% and 15% of explants with axillary bud break were observed, respectively. These results indicate that the genotype and cytokine source have influence on the response of in vitro establishment of nodal segments of chestnut variety, therefore, to establish a propagation system it is necessary to adjust a specific protocol for each variety.

Orchids require symbiotic fungi and/or specific conditions to germinate. Asymbiotic techniques have been shown successful for orchid germination. In Chile, Chloraea include many endemic, and potentially ornamental, terrestrial orchid species. In this study, individuals of Chloraea crispa, C. gavilu and C. virescens were manually autopollinated. The resulting capsules were sterilized and seeds were aseptically obtained. We evaluated asymbiotic germination in: Agar Water (AW), Knudson C (KC), Banana Culture Media (CMB), Tomato Culture Media (CMT), Malmgren Modified (MM), Murashige and Skoog (MS), and MS modified (MS1/2). Seeds were incubated in the dark at 24±1 ºC for 2 weeks. Then they were put in 16/8 h light/dark cycles for 14 weeks. We registered germination and embryo development in the different culture media. After 8 weeks, all tested Chloraea species germinated in most culture media. After 16 weeks, embryos in MM showed an evident shoot. In AW only the pre-germination stage was achieved. In C. gavilu germination was over 90% in MM, CMT, and CMB. In KC, a lower germination was obtained in all tested species compared to the other culture media, except for AW. Asymbiotic germination of endemic Chilean orchids could be a viable strategy for their conservation and propagation as ornamental species.

Castanea sativa Mill. es una especie de interés agroforestal ampliamente cultivada en Europa, cuya producción actual está principalmente enfocada en la obtención de fruto calidad marrón, apetecido en la industria gourmet. En Chile, esta especie puede ser cultivada exitosamente debido al clima y a la ausencia de enfermedades que la afecten. Sin embargo, no existe un sistema de propagación que permita la masificación de plantas para el establecimiento de huertos frutales. Ante esto, la micropropagación se presenta como una alternativa posible de aplicar, ya que es un método muy estudiado en esta especie. La propagación in vitro de Castanea sativa ha generado resultados exitosos en cuanto su introducción y multiplicación, sin embargo la propagación in vitro de variedades productoras de fruto marrón, es aún escasamente estudiada. Ante esta situación, para establecer un sistema de producción de plantas variedades de interés es necesario evaluar los efectos de algunas variables que influyen en el cultivo in vitro de leñosas, como son el genotipo y la fuente de citoquinina. Para esto, se estudiaron seis variedades de castaño provenientes de Italia y Francia y dos tipos de citoquininas, evaluándose su efecto en parámetros de inicio de establecimiento in vitro, tales como sobrevivencia, contaminación, formación de callo basal, apertura de yema axilar, entre otros. Los resultados muestran que en iguales condiciones de cultivo las variedades con mejor respuesta son Marrone Citta di Castello (CC) y Marrone Chiusa di Pesio (CP), en relación a la formación de callo basal y capacidad de reacción morfológica, donde el porcentaje de explantos fue superior al 80 y 85%, respectivamente, independiente del tipo de citoquinina utilizada. Por otra parte, la cantidad de explantos con yemas brotadas fue superior en el tratamiento con 0,5 mg L-1 de 6-bencilaminopurina (BAP) con un 100% en CC y 55% en CP, existiendo diferencia significativas con la respuesta obtenida en el tratamiento con 0,5 mg L-1 de Thidiazuron (TDZ), donde se observó un 10 y 15% de explantos con yemas brotadas, respectivamente. Estos resultados nos indican que el genotipo y la fuente de citoquinina influyen en la respuesta al establecimiento in vitro de segmentos nodales de variedades de castaño; por lo tanto, para establecer un programa de propagación es necesario ajustar un protocolo específico para cada variedad.

In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice.In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radiata.However, the capability of produce adventitious roots in gymnosperms decreases with aging.While it is true that some efforts have been made to identify markers or/and regulators of the aging process and adventitious rooting, molecular mechanisms that regulate both processes are scarcely known, especially at protein level.This research evaluated qualitative and quantitative changes in protein accumulation during the adventitious rooting process of P. radiata stem cuttings, with different rooting capabilities.Beside, an analysis of morpho-anatomical changes was performed in stem cuttings with high and low rooting capabilities, during the adventitious rooting process.It was observed that juvenile 1-year-old stem cuttings rooted in a 100%, while aged stem cuttings (3-year-old) presented only a 20% of rooting.According to the results of differential protein accumulation, univariate and multivariate analysis indicated that in total, 114 and 89 proteins were differentially accumulated in juvenile and aged cuttings, respectively.Also, identification of such proteins showed the presence of proteins related to cell wall organization and the presence of a protein related with proper distribution of auxin PIN transporter, both key in the new meristem formation process during adventitious rooting.

El entendimiento de los cambios bioquímicos que ocurren durante las distintas fases del enraizamiento hace posible obtener mayor porcentaje de enraizamiento de microbrotes en especies leñosas. Para diferenciar ambas especies y encontrar un marcador de la capacidad rizogénica, en el presente estudio se pretende caracterizar perfiles cinéticos de Ácido Indol Acético (AIA), Fenoles totales y Carbohidratos totales. Para esto se evaluaron microtallos de las especies Eucalyptus nitens (H. Deane & Maiden) Maiden y Eucalyptus globulus Labill. las cuales fueron tratadas con el método de la inducción lenta del enraizamiento en medio de cultivo Murashige & Skoog (1962) (MS) con las sales a la mitad, 30 g/L de sacarosa, suplementado con Ácido Naftalen Acético (ANA) durante 7 días en oscuridad. Posteriormente transferidos a sustrato vermiculita estéril con riego de medio de cultivo MS sin reguladores del crecimiento. Se recolectó material vegetal los días 0, 2, 7 y 20 días desde la inducción, se tomaron muestras de base de estacas para los análisis fitoquímicos. El AIA en los días 0 y 2 presentó altos valores que disminuyeron drásticamente durante las siguientes fases del enraizamiento días 7 y 20. Los compuestos fenólicos presentaron diferencias entre las dos especies en el tiempo evaluado, con valores significativamente más altos en Eucalyptus nitens (136 ug/gPS) que en E. globulus (29 ug/gPS). Los carbohidratos totales no mostraron diferencias entre las especies y se mantienen altos durante todo el tiempo en las dos especies de Eucalyptus. De acuerdo a lo obtenido, los compuestos fenólicos son buenos marcadores de la capacidad de enraizamiento adventicio ya que se diferenciaron significativamente en las dos especies de Eucalyptus.

The understanding of the biochemical changes that occur during the different phases of rooting makes it possible to obtain higher percentage microshoots rooting in woody species. To differentiate the two species and find a marker rhizogenic capacity in the present study is to characterize kinetic profile of Indole Acetic Acid content (AIA), total phenols and total carbohydrates. To this microshoots species Eucalyptus nitens (H. Deane & Maiden) Maiden and Eucalyptus globulus Labill. which were evaluated were treated with the method of the slow induction of rooting on Murashige & Skoog (1962) (MS) with the salts in half, supplemented with auxin naphthaleneacetic acid (NAA) for 7 days in darkness. Subsequently transferred to sterile vermiculite substrate irrigated crop MS medium without hormones. Plant materials on days 0, 2, 7 and 20 days from the induction manifolds, core samples were taken cuttings for analysis phytochemicals. The AIA on days 0 and 2, showed high values decreased dramatically during the next phases of rooting days 7 and 20. Phenolic compounds showed differences between the two species evaluated in time, with significantly higher values in Eucalyptus nitens (136 ug/gPS) in E. globulus (29 ug/gPS), total carbohydrates showed no differences between species and stay high all the time The AIA is essential for induction of rooting and is not subsequently required, as carbohydrates are not candidates for markers rhizogenic capacity not because they differ in the two species of Eucalyptus. According to the obtained phenolic compounds are good markers of the capacity of adventitious rooting since differed significantly in the two species of Eucalyptus.

A major problem in forest clonal productivity is the loss of morphogenetic capability with the increasing age of plants.However, despite of the importance of loss of morphogenetic competence, very little research has been done about the underlying mechanisms involved in this process.For this reason, a gene expression analysis using dot blot technique was performed in needles and stems of 1-and 3-year old Pinus radiata rootstock plants with a proved decrease in morphogenetic competence.Needles of one year old rootstock plants showed a higher number of up-regulated in genes mainly corresponding to photosynthesis and protein synthesis, degradation and modification, reflecting a higher number of active pathways in younger hedges, contrary to the older ones.Gene expression profiles found in stems are in agreement with those found in needles, indicating more active pathways in younger rootstock plants than in older ones.Several transcripts regulating transcription and translation were up-regulated in young competent tissues.Three-year-old stems presented an increase in the expression of an ethylene response factor, involved in plant organ senescence, indicating that pathways involved in senescence and ageing might inhibit the adventitious root formation, as in the older cuttings.

The low photon flux density (PFD) under in vitro conditions and sucrose added to the culture medium negatively limits the photochemical activity and photoprotective mechanisms of microshoots.In this work we hypothesize that decreasing sucrose in the culture medium in combination with increasing irradiance, could improve the photosynthesis and consequently the in vitro growth.We evaluated the effect of exogenous sucrose (30 and 5 g•L -1 , HS and LS, respectively), under different PFD (50 and 150 µmol photons m -2 •s -1 , LL and HL, respectively) on the photosynthetic performance and growth of Castanea sativa microshoots.Decreasing sucrose negatively affected the physiological attributes evaluated.Only chloroplast ultrastructure was improved by LS; however this did not lead to an improved in photosynthesis or growth.HL HS produced an increase in photosynthetic activity and chlorophyll contents, reaching under these conditions a higher proliferation rate and biomass production.Additionally, the photochemical activity (electron transport rate and nonphotochemical quenching) was improved by HL.Thus, our results suggest that, at least for C. sativa HL is beneficial during the in vitro culture, improving photosynthetic performance as well as growth, but this is only possible in the presence of moderate concentrations of sucrose added to the culture medium.

Se probó el efecto de algunas fuentes de nitrógeno orgánico como caseína hidrolizada y los aminoácidos L-Glutamina y L-Serina en el proceso de embriogénesis somática secundaria directa, empleando como explantes embriones somáticos de Nothofagus alpina inducidos desde cotiledones aislados de semillas maduras. Los mayores porcentajes de embriogénesis secundaria directa fueron obtenidos en medio base BTM y vitaminas MS, sin reguladores del crecimiento vegetal y en este medio más ANA, BAP y caseína hidrolizada. Sin embargo, el peso fresco de las masas de proliferación fue superior en presencia de una fuente adicional de nitrógeno orgánico. Bajo el tratamiento con reguladores del crecimiento y caseína hidrolizada también se produjo la mayor cantidad promedio de embriones producidos por explanto, aunque no hubo diferencias significativas con el tratamiento que contuvo L-Glutamina, donde el crecimiento de callo fue significativamente menor. Mediante subcultivos alternados entre medio base y medio con ANA, BAP y caseína hidrolizada, se logró la proliferación del cultivo embriogénico de manera directa, estable durante más de dos años y con baja incidencia de callo.

In forest production systems, vegetative propagationof elite clones through adventitiousrooting is a common practice. In Chile, adventitious rooting is the main methodologyfor vegetative reproduction of Pinusradiata. However, the capability of produce adventitious roots ingymnosperms decreases with aging. While it is true that some efforts have beenmade to identify markers or/and regulators of the aging process andadventitious rooting, molecular mechanisms that regulate both processes arescarcely known, especially at protein level. This research evaluatedqualitative and quantitative changes in protein accumulation during theadventitious rooting process of P.radiata stem cuttings, with different rooting capabilities. Beside, ananalysis of morpho-anatomical changes was performed in stem cuttings with highand low rooting capabilities, during the adventitious rooting process. It wasobserved that juvenile 1-year-old stem cuttings rooted in a 100%, while agedstem cuttings (3-year-old) presented only a 20% of rooting. According to the results ofdifferential protein accumulation, univariate and multivariate analysisindicated that in total, 114 and 89 proteins were differentially accumulated injuvenile and aged cuttings, respectively. Also, identification of such proteinsshowed the presence of proteins related to cell wall organization and thepresence of a protein related with proper distribution of auxin PINtransporter, both key in the new meristem formation process during adventitiousrooting.

The aim of the present study was to evaluate the applicability of maximal photochemical efficiency of photosystem II (Fv/Fm) as an early estimate of P. radiata micrografts viability coming from different position (basal vs. apical) in the ortets. We hypothesize that Fv/Fm variation is a good indicator of micrograft’s viability and phenological stage during micrograft development. The micrografts were established in QL medium supplemented whit 0.1 mg·L-1 IBA and 1 mg·L-1 BAP and cultured at 25°C ± 2°C and 80 μmol photons m-2s-1 of photosynthetic active radiation by 16 h per day. During the establishment and consolidation phase, we found significant differences in Fv/Fm with respect to time and buds positions provenience. During establishment, basal shoot tips have lower Fv/Fm than apical shoot tips, which agrees with the lowest viability (35%). However, during the consolidation phase, the trend changed and basal shoot tips presented higher Fv/Fm than apical shoot tips and showed an increase in ETR and NPQ, with respect to apical shoots and ortet. Although the measurement of fluorescence parameters implies the insertion of the fluorometer sonde in vitro, this implies aseptic considerations, but always conveies a contamination risk. We conclude that fluorescence (Fv/Fm, ETR, NPQ) can be indicators of the micrograft’s development according to the shoot tips position in the ortet and can be useful early-indicators of the scions’ physiological condition during micrograft transition from establishment to consolidation.

Adequate in vitro micro-environments are crucial to induce life compatible leaf development. Key morphological and physiological traits are needed to allow ex vitro survival. We study, how in vitro light and ventilation affect physiological performance and survival of ex vitro Castanea sativa plantlets. In vitro treatments consisted of two irradiances of 50 and 150 µmol m−2 s−1 in ventilated vessels (VL50 and VL150, respectively), compared to traditional cultures at 50 µmol m−2 s−1 in non-ventilated vessels (NVL50). After the exposure to each condition a photoinhibitory treatment (PhT) was also applied to study whether the above in vitro conditions exerted photoprotection and facilitated the recovery of C. sativa during sudden ex vitro transfer. During rooting, a decrease in net photosynthesis (Psat), electron transport rate (ETRII) and maximal efficiency of PSII (F v /F m ) were observed. Transpiration rates (E) decreased, concomitantly with a rise in water use efficiency (WUE), mainly in microplants originating from ventilated treatments (V). Throughout this stage, the PhT was lethal for all in vitro treatments. During acclimation, the number and leaf size increased principally in plantlets originating from V treatments. These microplants were also able to recover their ETR and F v /F m . Initially, the PhT produced a drastic drop in Fv/Fm of plantlets in all treatments however they did show a tendency to recover. Transferring plantlets to the greenhouse produced a decrease in the Psat in all treatments; however, over time Psat increased reaching values of 3.2 and 5.3 μmol CO2 m−2 s−1 in microplants originating from VL50 and VL150, respectively. Transpiration rate were similar in all treatments and remained at levels of about 0.9 mmol H2O m−2 s−1; thus, WUE increased significantly, reaching values of almost 3.8 µmol CO2/mmol H2O in microplants originating from VL150. After the PhT, all of the plantlet’s recovery capacity increased concomitantly with their dynamic heat dissipation and their de-epoxidation capacity. Our results suggest that managing in vitro conditions can improve plantlets photosynthetic performance in early stages after ex vitro transfer, playing a key role in the ameliorating the transfer stress.