Luma Apiculata Research Articles

Early Growth and Physiological Acclimation to Shade and Water Restriction of Seven Sclerophyllous Species of the Mediterranean Forests of Central Chile.

The success of using active restoration in Mediterranean-type climate zones mostly depends on an appropriate matching of plant species and specific management prescriptions upon establishment. In this study, we assessed the early growth and short-term physiological acclimation of seven common species found in the sclerophyllous forests in central Chile to water restriction and shading. We established a nursery experiment that included three treatments (T0: sun-exposed and water-restricted, T1: sun-exposed and fully irrigated, and T2: shaded and fully irrigated) and seven tree species differing in their shade and drought tolerance (Quillaja saponaria Molina, Aristotelia chilensis (Mol.) Stuntz, Peumus boldus Molina, Lithraea caustica (Mol.) Hook. and Arn, Luma apiculata (DC.) Burret, Colliguaja odorifera Molina, and Escallonia pulverulenta (Ruiz and Prav.) Pers). We measured the increment in seedling height and different leaf morpho-physiological traits during two months in the dry season. Based on the measured traits, none of the species took advantage of the higher water availability in T1 relative to T0, but most of the species responded to the shade in T2, regardless of their shade or drought tolerance. Height increments due to shade varied from 0% in P. boldus to 203% in L. apiculata. Overall, all the species responded similarly to the treatments in specific leaf area, chlorophyll content index, photosynthetic rate, stomatal conductance, and intrinsic water use efficiency. This suggests that the species exhibited similar acclimation patterns of these parameters to shade and drought, even regarding the variation in midday xylem water potential found in the water-restricted treatment T0 (from -1.5 MPa in P. boldus to -3.1 MPa in E. pulverulenta). In this study, shading had a higher positive effect on the seedling performance of sclerophyllous species than watering, which at operational level highlights the need for investing in tree shelters when using these species in restoration programs.

Innovative Integration of Arrayan (Luma apiculata) Extracts in Chitosan Coating for Fresh Strawberry Preservation.

Strawberries are a rich source of vitamins and antioxidants, among other nutrients, but they are highly susceptible to mechanical injuries, dehydration, and microbial spoilage, and thus have a limited post-harvest shelf-life. Bioactive edible coatings have been studied to decrease or prevent these damages. In this study, ethanolic extracts of Arrayan (Luma apiculata), a traditional berry from the south of Chile, were used to enrich a chitosan-based edible film and coat fresh strawberries. A long-term storage (10 °C) study was conducted to determine the strawberries' weight loss, microbial stability, fruit firmness impact, and antioxidant activity. Later, a sensory panel was conducted to determine overall consumer acceptance. Our results show that the bioactive coating inhibited the growth of different pathogenic bacteria and spoilage yeast. In the stored strawberries, the weight loss was significantly lower when the bioactive coating was applied, and the samples' firmness did not change significantly over time. Microbial growth in the treated strawberries was also lower than in the control ones. As expected, the antioxidant activity in the coated strawberries was higher because of the Arrayan extract, which has high antioxidant activity. Regarding sensory qualities, the covered strawberries did not show significant differences from the uncoated samples, with an overall acceptance of 7.64 on a 9-point scale. To our knowledge, this is the first time an edible coating enriched with Arrayan extracts has been reported as able to prevent strawberries' decay and spoilage.

Homogeneous colleters in Myrteae (Myrtaceae).

Colleters are secretory structures characteristic of the apices of more than 60 botanical families. In the Myrtaceae, three types of colleters were previously described: petaloid, conical, and euriform. In Argentina, most species of the Myrtaceae family grow in subtropical regions and a few in the temperate-cold zones of Patagonia. We evaluated the vegetative buds of five species of the subfamily Myrtoideae, tribe Myrtea: Amomyrtus luma, Luma apiculata, and Myrceugenia exsucca, native to the temperate rainforests of Patagonia and Myrcianthes pungens and Eugenia moraviana from the riparian forest of northwestern Corrientes, in order to analyze the presence and morphological types and main secretion products of colleters. Optical and scanning electron microscopy was used to identify the presence of colleters in vegetative organs. Histochemical tests were performed to identify the main secretion products in these structures. The colleters are on the inner side of the leaf primordia and cataphylls and on the edge of the petiole, where they replace the stipules. They are classified as homogeneous because they consist of epidermis and internal parenchyma, both formed by cells with similar characteristics. They lack vascularization and originate from the protodermis. The colleters are of the conical type in L. apiculata, M. pungens, and E. moraviana and of the euriform type in A. luma and M. exsucca, the latter being identified by its dorsiventrally flattened shape. Histochemical tests showed the presence of lipids, mucilage, phenolic compounds, and proteins. This is the first time that colleters have been described in the analyzed species; the taxonomical and phylogenetic importance of this structures is discussed in relation to the Myrtaceae family.

Simacauda dicommatias (Meyrick, 1931) (Lepidoptera: Incurvariidae), a South American species established in Cornwall, new to the British Isles and unknown in mainland Europe, with first details of its biology

An account is provided of the discovery of Simacauda dicommatias (Meyrick, 1931) (Incurvariidae) at 26 sites in Cornwall, England, all in the larval stage, being initially leafminers then case-bearers on South American members of the Myrtaceae, mainly Luma apiculata (DC.) Burret, with moths being reared, and species identification confirmed by genitalic examination. This is the first time that the species has been found in the British Isles and it is unknown in mainland Europe. S. dicommatias is native to Argentina and Chile where it occurs in Andean (Valdivian) temperate rainforests. The biology appears to be unknown there, although adults have been collected around stands of L. apiculata. The generic identity is additionally confirmed by a DNA barcode (658 base pairs) obtained from the abdomen of one specimen from Cornwall. This matches (within 1.69% divergence for 296 comparable nucleotides) a COI fragment on BOLD from a specimen collected in Parque Nacional Puyehue, Chile, which is there misidentified as Simacauda virescens Nielsen & Davis, 1981, but is 8.75% divergent from another two short sequences (correctly) so identified. It is known that William Lobb, whilst employed by James Veitch & Son, imported L. apiculata (now an invasive species in the British Isles), with one or more other Chilean Myrtaceae in the mid-1840s. It remains to be tested if S. dicommatias may prove to be the earliest known example of an established adventive insect accidentally introduced from South America to the British Isles.

Towards a rational design of natural deep eutectic solvents for the extraction of polyphenols from Luma apiculata

In this article, we present a complementary experimental and theoretical study for designing a task-specific medium for the ultrasound extraction of polyphenols ofLuma apiculata. Our results reveal that choline chloride-based DESs are suitable candidates as extraction media. To capture the role of the solvent in the extraction process, we employed molecular dynamics simulation of a model solute surrounded by different DESs. Results showed that an adequate DES should have an organic acid, an amine or quaternary ammonium salt, a content of water for the formation of the eutectic mixture, and an acidic anion. The importance and role of each component could be rationalized by their synergetic solvation of the polyphenols.

Honeybee Pollen From Southern Chile: Phenolic Profile, Antioxidant Capacity, Bioaccessibility, and Inhibition of DNA Damage.

Honeybee pollen (HBP) chemical composition is highly variable conforming to the floral and geographical origin of the pollen grains. The beneficial effects and functional properties of the HBP are well-known and have been mainly attributed to their high content of antioxidant polyphenols. In this work, twelve HBPs samples from the Southern region of Chile (X Región de Los Lagos) were characterized for the first time according to their botanical origin, phenolic composition, and antioxidant activity. The in vitro gastrointestinal digestion assay was done to simulate the human upper digestive tract. Selected honeybee pollen extracts (HBPEs) were assessed as bioaccessible fractions during an in vitro gastrointestinal digestion. Contents of phenolic compounds, antioxidant capacity, and recovery index of quercetin, myricetin, and cinnamic acid were monitored in different steps of gastrointestinal digestion. Furthermore, the protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals was evaluated. The introduced species Brassica rapa L. (Brassicaceae), Lotus pedunculatus Cav. (Fabaceae), and Ulex europaeus L. (Fabaceae) predominated in all the HBPs analyzed, while the native species Buddleja globosa Hope (Scrophulariaceae), Luma apiculata (DC.) Burret (Myrtaceae), Embothrium coccineum J.R. Forst. & G. Forst. (Proteaceae) and Eucryphia cordifolia Cav. (Cunoniaceae) appeared less frequently. The content of polyphenols and antioxidant capacity in HBPEs achieved full bioaccessibility at the end of the intestinal digestion step. However, results obtained by a state-of-the-art technique (i.e. HPLC-DAD) demonstrated relatively low values of bioaccessible quercetin and cinnamic acid after the digestion process. In contrast, myricetin showed a high bioaccessibility in the intestinal digestion steps. The protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals showed promising results (up to 91.2% protection). In conclusion, HBPs from the X Region de Los Lagos are rich sources of phenolic antioxidants that protect DNA from strand breakage. Therefore, the potential of HBPEs in preventing gastric and/or intestinal cancer should be further considered.

Changes of cell wall-associated polysaccharides and sugars during development and ripening of arrayan (Luma apiculata) and lleuque (Prumnopitys andina) fruits

Changes of cell wall-associated polysaccharides and sugars during development and ripening of arrayan (Luma apiculata) and lleuque (Prumnopitys andina) fruits

Multivariable optimization of ultrasound-assisted extraction for the determination of phenolic and antioxidants compounds from arrayan (Luma apiculata (DC.) Burret) leaves by microplate-based methods and mass spectrometry

The present study reports a multivariable optimization of ultrasound-assisted extraction of phenolic compounds from arrayan leaves. The parameters ethanol percentage in extraction solvent, temperature and extraction time, and mass to solvent ratio were optimized applying full factorial and central composite designs. According to the models, the optimal extraction conditions were: 42% of ethanol, extraction time of 27 min, extraction temperature of 50ºC and a mass to solvent ratio of 1:33.4 g mL−1. Under these conditions, a total phenolic content (TPC) of 128.16 ± 1.18 and 593.64 ± 6.49 mg of gallic acid equivalent per g of dry weight (DW) were determined in raw extract (RE) and polyphenols-rich extract (PRE), which was obtained by semi-preparative chromatography on XAD-7 column. Antioxidant capacity determined via FRAP analysis showed values of 1349.53 ± 28.99 and 6175.47 ± 127.64 µmol Trolox equivalent per g of DW for RE and PRE, and DPPH IC50 values of 831.40 ± 0.80 and 132.21 ± 2.51 µg mL−1, respectively. Polyphenols profile analyzed by liquid chromatography-mass spectrometry showed the presence of quercetin 3-ß-D-glucoside, myricetin, quercetin, kaempferol 3-glucoside and gallic acid; the latter compounds are reported for the first time in arrayan leaves. Due to the presence of polyphenols, antiviral activity was assayed over norovirus and hepatitis A showing a significant dose-dependent effect.

Effect of Freeze Crystallization on Quality Properties of Two Endemic Patagonian Berries Juices: Murta (Ugni molinae) and Arrayan (Luma apiculata).

This work studied the effects of centrifugal block freeze crystallization (CBFC) on physicochemical parameters, total phenolic compound content (TPCC), antioxidant activity (AA), and process parameters applied to fresh murta and arrayan juices. In the last cycle, for fresh murta and arrayan juices, the total soluble solids (TSS) showed values close to 48 and 54 Brix, and TPCC exhibited values of approximately 20 and 66 mg gallic acid equivalents/100 grams dry matter (d.m.) for total polyphenol content, 13 and 25 mg cyanidin-3-glucoside equivalents/100 grams d.m. for total anthocyanin content, and 9 and 17 mg quercetin equivalents/100 grams d.m. for total flavonoid content, respectively. Moreover, the TPCC retention indicated values over 78% for murta juice, and 82% for arrayan juice. Similarly, the AA presented an increase over 2.1 times in relation to the correspondent initial AA value. Thus, the process parameters values were between 69% and 85% for efficiency, 70% and 88% for percentage of concentrate, and 0.72% and 0.88 (kg solutes/kg initial solutes) for solute yield. Therefore, this work provides insight about CBFC on valuable properties in fresh Patagonian berries juices, for future applications in health and industrial scale.

Ethnopharmacology, Phytochemistry and Biological Activities of Native Chilean Plants.

The native flora of Chile has unique characteristics due to the geographical situation of the country, with the vast desert in the North, Patagonia in the South, the Andean Mountains on the east and the Pacific Ocean on the west. This exclusivity is reflected in high concentrations of phytochemicals in the fruits and leaves of its native plants. Some examples are Aristotelia chilensis (Molina), Stuntz (maqui), Berberis microphylla G. Forst. (calafate), Peumus boldus Molina (boldo), Ribes magellanicum Poir. (Magellan currant), Ugni molinae Turcz. (murtilla), Rubus geoides Sm. (miñe miñe), Drimys winteri J.R.Forst. & G.Forst. (canelo), Luma apiculata (DC.) Burret (arrayán) distributed throughout the entire Chilean territory. Some of these Chilean plants have been used for centuries in the country's traditional medicine. The most recent studies of phytochemical characterization of parts of Chilean plants show a wide spectrum of antioxidant compounds, phenolic components, terpenoids and alkaloids, which have shown biological activity in both in vitro and in vivo studies. This manuscript covers the entire Chilean territory characterizing the phytochemical profile and reporting some of its biological properties, focusing mainly on antioxidant, anti-inflammatory, antimicrobial, chemopreventive and cytotoxic activity, and potential against diabetes, metabolic syndrome and gastrointestinal disorders.

Antimicrobial Activity of Extracts of Two Native Fruits of Chile: Arrayan (Luma apiculata) and Peumo (Cryptocarya alba)

Arrayan and peumo fruits are commonly used in the traditional medicine of Chile. In this study, the concentration of the extracts halving the bacterial viability and biofilms formation and disruption of the drug-sensitive and drug-resistant strains of Staphylococcus aureus and Pseudomonas aeruginosa was determined. The chemical composition of extracts was analyzed by high-resolution liquid chromatography coupled with mass spectrometry (U-HPLC/MS). The arrayan extract (Inhibitory concentration IC50 0.35 ± 0.01 mg/mL) was more effective than peumo extract (IC50 0.53 ± 0.02 mg/mL) in the inhibition of S. aureus planktonic cells. Similarly, the arrayan extract was more effective in inhibiting the adhesion (S. aureus IC50 0.23 ± 0.02 mg/mL, P. aeruginosa IC50 0.29 ± 0.02 mg/mL) than peumo extracts (S. aureus IC50 0.47 ± 0.03 mg/mL, P. aeruginosa IC50 0.35 ± 0.01 mg/mL). Both extracts inhibited quorum sensing in a concentration-dependent manner, and the most significant was the autoinducer-2 type communication inhibition by arrayan extract. Both extracts also disrupted preformed biofilm of P. aeruginosa (arrayan IC50 0.56 ± 0.04 mg/mL, peumo IC50 0.59 ± 0.04 mg/mL). However, neither arrayan nor peumo extracts disrupted S. aureus mature biofilm. U-HPLC/MS showed that both fruit extracts mainly possessed quercetin compounds; the peumo fruit extract also contained phenolic acids and phenylpropanoids. Our results suggested that both extracts could be used as natural antimicrobials for some skin and nosocomial infections.

Antimicrobial activity of Luma apiculata against resistant strains of Staphylococcus aureus and Klebsiella pneumoniae

Bacterial resistance is the mechanism through which the bacteria can decrease the action of antimicrobial agents. Studies have reported an antimicrobial action of Luma apiculata, however, there are no in vitro studies demonstrating the effect of this plant against multidrug-resistant bacteria. The objective of this study was to explore the antimicrobial properties of alcoholic extract of Luma apiculata against standard multi-resistant bacterial pathogens. Multidrug-resistant strains of Staphylococcus aureus ATCC 43300 (MRSA) and Klebsiella pneumoniae ATCC BAA 1705 (CRKP) were incubated independently for 72 h at 37oC with different concentrations (1-10,000 µg/mL) of alcoholic extract of Luma apiculata. The growth curve was studied up to 72 hours. The minimum inhibitory concentration (MIC) was determined by broth macrodilution method. The agar diffusion method was used to examine bacteriostatic activity and bactericidal activity was evaluated by a commercial kit and analyzed by flow cytometry. Analyses of chromatographic data, as well as mass spectrometry, were performed to determine the main compounds present in the extracts. Luma apiculata leaves extracts showed bactericidal activity and was effective attenuating growth in both bacterial strains. Thus, Luma apiculata could represent a natural alternative against multidrug-resistant bacterial strains. However, further studies should be undertaken to test their clinical utility. Keywords: Antimicrobial activity; Arrayan; Flavonoids; Medicinal plants; Multiresistant bacteria http://dx.doi.org/10.19045/bspab.2019.80140

Screening of Native and Exotic Tree Species in Chile for Element Absorption from Dairy Slurry

We studied the effect of fertigation with cattle slurry on native and exotic arboreal tree species in Chile. The objectives were to identify the most promising species for buffer strips to mitigate the stream pollution in dairy facilities, to determine where most nutrients accumulate (leaves, stems, or roots), and to test whether the native species are or are not a better biofilter than the exotic ones. We hypothesized that the individuals that were fertilized would have a higher nutrient concentration, nutrient accumulation, and growth than those non-fertilized. N and K concentrations were similar in fertilized trees and in the controls, while the P, Ca, Mg, and Na concentrations were higher in the control than those in the fertilized trees. Most species responded positively to fertilization on a dry matter basis. Luma apiculata, Drimys winteri, and Blepharocalyx cruckshanksii responded to fertilization showing a greater height and diameter growth. Generally, nutrients accumulated in leaves. Overall, the exotic Eucalyptus nitens was the species that accumulated more nutrients given its large growth rate. The native species that more commonly stood out in this study were D. winteri, Nothofagus dombeyi, and L. apiculata. In general, a minor proportion of the applied slurry was absorbed by trees, and we recommend the use of trees in biofilters as a complement to crop and pasture absorption.

The effect of phenolic compounds on the green synthesis of iron nanoparticles (FexOy-NPs) with photocatalytic activity

The green synthesis of nanoparticles allows for obtaining nanomaterials using plant extracts, avoiding the use of toxic and dangerous chemical compounds. The aim of this study was to evaluate the effect of phenolic compounds in plant extracts on the synthesis of iron oxide nanoparticles (FexOy-NPs) with photocatalytic activity. Accordingly, the phenolic content in 11 plant extracts was evaluated by the Folin–Ciocalteu (F–C) method, and the iron-reducing capacity was evaluated by the ferric-reducing antioxidant power method (FRAP). From the F–C and FRAP analyses, the Luma apiculata (LAL), Phragmites australis (PAL) and Eucalyptus globulus (EGL) extracts were selected and analyzed by HPLC coupled with a diode array detector (DAD) to identify and quantify the phenolic compounds. Using the three selected extracts, FexOy-NPs were synthesized, which were then characterized by UV–Vis spectroscopy, FTIR, DLS, zeta potential, SEM-EDX, and Raman and diffuse reflectance spectroscopy. The SEM-EDX, DLS and zeta potential analyses showed that the FexOy-NPs were spherical, stable and nanosized. The FRAP, F–C and FTIR analyses indicated the role of phenolic compounds in the formation and stabilization of FexOy-NPs. It was possible to establish a direct relationship between the composition of the phenolic compounds and the reducing capacity of the extracts. In addition, it was found that phenolic compounds and their concentrations are associated with the size and type of FexOy-NPs obtained. Furthermore, it was proposed that types of phenolic compounds influence the formation of different phases of FexOy-NPs. The photocatalytic activity of the FexOy-NPs was demonstrated by diffuse reflectance spectroscopy and decolorization of a dye under visible radiation.

Structural differentiation among annual shoots as related to growth dynamics in Luma apiculata trees (Myrtaceae)

A close examination of axis differentiation is key to the understanding of plant architecture and its ecological consequences. The present study was aimed at evaluating the relationship between shoot size/structure and shoot growth dynamics in Luma apiculata (Myrtaceae), a widely distributed and cultivated but little investigated Andean-Patagonian woody species. We assessed (a) organ preformation in apical buds, (b) shoot growth through repeated observations of labeled axes, (c) axillary production, leaf area, stem volume, dry mass of leaves, stem and reproductive structures, and allometric relationships for annual shoots of different sizes. The number of preformed organs in apical buds of L. apiculata averages seven nodes and exhibits little variability, in contrast with the highly variable growth period (from few weeks up to more than six months) and the size reached by annual shoots. The leaf area/stem volume ratio increased more sharply during shoot extension in short than in long shoots. Stem thickness was proportionally higher than other shoot-size measures in short shoots and long shoots as compared to intermediate-size shoots. Both the presence and the position of branches along shoots varied notably with shoot size. Proportional mass and meristem allocation to fruit production decreased with shoot size. Unlike many other broadleaved temperate and temperate-cold tree species so far studied, the size reached by L. apiculata shoots developed in the same year varies notably among axes in the same topological position, and seems to depend largely on the expansion of non-preformed organs. A low dependency of shoot growth on organ preformation may increase plasticity in axis structure, at the cost of a less hierarchical (more shrubby) architecture. Simultaneous organ differentiation and expansion may allow plants to fine-tune shoot structure to the prevailing conditions during the growing season, and represent an advantage whenever conditions favourable for growth exhibit high between-year variations.

Diversity of Phytophthora species in Valdivian rainforests and association with severe dieback symptoms

AbstractThe Valdivian rainforest, one of the global hotspots of biodiversity, is a temperate rainforest originating as a Tertiary relic from the supercontinent Gondwana. In November 2014, a survey of Phytophthora diversity was performed in 13 natural forest stands and 20 forest streams and rivers in two protected areas near Valdivia and in a temperate montane forest in the Concepción area. One planted stand each of the introduced tree species Castanea sativa and Fagus sylvatica were also included. Using baiting assays, eight described species and four previously unknown taxa of Phytophthora were isolated from 86% of the 50 rhizosphere soil samples from seven of the eight tree species sampled in 12 forest stands, and from 20 streams: P. chlamydospora, P. cinnamomi, P. kernoviae, P. lacustris, P. plurivora, P. pseudosyringae, P. ×cambivora, P. ×stagnum, P. valdiviana nom. prov. from Clade 2b, P. madida nom. prov. from Clade 8a, and P. chilensis nom. prov. and P. pseudokernoviae nom. prov. The latter two species are the closest relatives of P. kernoviae from Clade 10. Phytophthora pseudokernoviae nom. prov. was also isolated from necrotic leaves of Drimys winteri. From the Valdivia river, a swarm of three Clade 6 hybrids was recovered. Each hybrid isolate resulted from multiple reticulation events with P. thermophila as maternal and both P. amnicola and P. chlamydospora as paternal parents. In addition, three previously unknown and recently described Nothophytophthora species, N. caduca, N. chlamydospora and N. valdiviana, were isolated from several forest streams. Phytophthora cinnamomi, the most common and widespread species in soils of native forests, was associated with severe dieback of Valdivian rainforest trees, in particular D. winteri, Luma apiculata, Nothofagus dombeyi and the endangered Saxegothaea conspicua. A first pathogenicity test demonstrated high aggressiveness of P. cinnamomi to several native tree species, including N. dombeyi, Blepharocalyx cruckshanksii and Gevuina avellana.

Fleshy fruits as a lifebelt for seeds and the potential polychory of two wetland trees of temperate Chilean forests

The seeds of fleshy-fruited species growing in aquatic environments fall into water, with or without their pericarp depending upon whether gravity or animals disperse the seeds, with consequences little explored for seed ecology and dispersal in wetlands. In this study, we evaluated the germination of seeds with and without fleshy pericarp after water exposure (from 7 to 90 days), timing of fruit flotation and germination percentage from within intact fruits of two fleshy-fruited Myrtaceae trees of the Chilean temperate forests, Luma apiculata and Blepharocalyx cruckshanksii. For both species, we found greater germination in flooded seeds with pericarp than without, maximum fruit flotation for about a month, although buoyancy was reduced faster in B. cruckshanksii, and seedling emergence from inside fruits occurred in a grater percentage in B. cruckshanksii. These results show that the fleshy pericarp protects seeds from negative water effects, allowing hydrochory and it does not impede germination. Thus, there is a potential advantage for seeds being dispersed with their fleshy cover in wetland habitats. We assert that these species have multiple dispersal mechanisms (polychory) operating in wetlands, with consequences for their dispersal and recruitment.

Carbon allocation to growth and storage in two evergreen species of contrasting successional status.

A prevailing hypothesis in forest succession is that shade-tolerant species grow more slowly than shade-intolerant species, across light conditions, because they prioritize carbon (C) allocation to storage. We examined this hypothesis in a confamilial pair of species, including one of the fastest-growing tree species in the world (Eucalyptus globulus) and a shade-tolerant, slow-growing species (Luma apiculata). Seedlings were subjected to one out of four combinations of light (high vs. low) and initial defoliation (90% defoliated vs. nondefoliated) for four months. Growth, C storage concentration in different organs, leaf shedding, and lateral shoot formation were measured at the end of the experiment. Eucalyptus globulus grew faster than L. apiculata in high light, but not in low light. Both species had lower C storage concentration in low than in high light, but similar C storage concentrations in each light condition. Defoliation had no effect on C storage, except in the case of the old leaves of both species, which showed lower C storage levels in response to defoliation. Across treatments, leaf shedding was 96% higher in E. globulus than in L. apiculata while, in contrast, lateral shoot formation was 87% higher in L. apiculata. In low light, E. globulus prioritized C storage instead of growth, whereas L. apiculata prioritized growth and lateral branching. Our results suggest that shade tolerance depends on efficient light capture rather than C conservation traits.

Physiological and morphological responses to permanent and intermittent waterlogging in seedlings of four evergreen trees of temperate swamp forests.

Waterlogging decreases a plant's metabolism, stomatal conductance (gs) and photosynthetic rate (A); however, some evergreen species show acclimation to waterlogging. By studying both the physiological and morphological responses to waterlogging, the objective of this study was to assess the acclimation capacity of four swamp forest species that reside in different microhabitats. We proposed that species (Luma apiculata [D.C.] Burret. and Drimys winteri J.R. et G. Forster.) abundant in seasonally and intermittently waterlogged areas (SIWA) would have a higher acclimation capacity than species abundant in the inner swamp (Blepharocalyx cruckshanksii [H et A.] Mied. and Myrceugenia exsucca [D.C.] Berg.) where permanent waterlogging occurs (PWA); it was expected that the species from SIWA would maintain leaf expansion and gas exchange rates during intermittent waterlogging treatments. Conversely, we expected that PWA species would have higher constitutive waterlogging tolerance, and this would be reflected in the formation of lenticels and adventitious roots. Over the course of 2 months, we subjected seedlings to different waterlogging treatments: (i) permanent (sudden, SW), (ii) intermittent (gradual) or (iii) control (field capacity, C). Survival after waterlogging was high (≥80%) for all species and treatments, and only the growth rate of D. winteri subjected to SW was affected. Drimys winteri plants had low, but constant A and g during both waterlogging treatments. Conversely, L. apiculata had the highest A and g values, and g increased significantly during the first several days of waterlogging. In general, seedlings of all species subjected to waterlogging produced more adventitious roots and fully expanded leaves and had higher specific leaf area (SLA) and stomatal density (StD) than seedlings in the C treatment. From the results gathered here, we partially accept our hypothesis as all species showed high tolerance to waterlogging, maintained growth, and had increased A or g during different time points of waterlogging. Differences in leaf (SLA) and stomata functioning (gs, StD) plasticity likely allows plants to maintain positive carbon gains when waterlogging occurs. The species-specific differences found here were not entirely related to microhabitat distribution.

Crecimiento anual de cuatro especies arbóreas con yemas desnudas nativas de los bosques templados húmedos de Patagonia.

Las especies vegetales que habitan en regiones con bajo nivel de estacionalidad en el clima suelen presentar rasgos morfo-arquitecturales que ocurren con menor frecuencia en especiesde regiones con clima estacional. El objetivo de este estudio fue evaluar el crecimiento primario en vivero de cuatro especies leñosas típicas de los bosques templados húmedos de Patagonia, conocidoscomo selva valdiviana, donde el grado de estacionalidad es menos marcado que en otros bosques patagónicos. Las especies estudiadas, Aextoxicon punctatum, Luma apiculata, Myrceugenia exsucca ySophora microphylla, comparten con muchas especies tropicales la posesión de yemas desnudas. Se evaluaron, durante un año calendario, la fenología, el crecimiento y la ramificación del eje principal de plantas marcadas. El crecimiento primario en estas especies fue marcadamente estacional, como en se ha registrado en especies arbóreas con yemas escamosas con las que coexisten. Sin embargo, se detectaron notables diferencias intra- e inter-específicas en el inicio y la finalización del crecimiento; L. apiculata y M. exsucca (Myrtaceae) presentaron mayores variaciones que las restantes dos especies.Nuestros resultados indican la intervención de varios factores reguladores del crecimiento primario en las especies estudiadas, como ocurre en especies con crecimiento continuo.