Cedrela Fissilis Vell Research Articles

Morphoanatomical alterations in extrafloral nectaries of Cedrela fissilis Vell. (Meliaceae), a native species of the Atlantic Forest, in response to simulated acid rain

Acid rain is one of the major contributors to the loss of tropical forest. Although the effects of acid rain in leaf anatomy have been widely studied, its impact on specialized secretory structures remains unknown. The aim of this study was to investigate the morphoanatomical changes in the extrafloral nectaries of Cedrela fissilis in response to simulated acid rain. Each seedling was sprayed with 50 ml of an acidic solution daily for 19 consecutive days. Anatomical and micromorphological changes in the nectaries were described. The treated plants exhibited plasmolysis and disruption of epidermal cells, cell collapse, hypertrophy, plasmolysis, phenolic and starch accumulation in the nectar-secreting cells, and the formation of a wound healing tissue. The results indicate that the nectaries of C. fissilis undergo alterations when exposed to acid rain, which may compromise the functioning of the entire structure and potentially impact plant-insect ecological interactions.

Does climate change alter the nutrient trends of Cedrela fissilis Vell. trees in the southern Brazilian Amazon?

BackgroundThe increase in the frequency and intensity of droughts is pointed out as one of the main factors altering biogeochemical cycles in the Amazon basin. An eco-nutritional approach using X-ray fluorescence micro-analysis (µXRF) is proposed to verify the long- and short-term effects of droughts on the growth and xylem nutrient concentrations of Cedrela fissilis Vell.MethodsFourteen radii were selected from a tree-ring width chronology and X-rayed by Itrax Multiscanner. Profiles of ring width, wood density, and concentrations of aluminum (Al), phosphorus (P), sulfur (S), calcium (Ca), potassium (K), manganese (Mn), iron (Fe) and strontium (Sr) together with Al/Ca, Ca/Mn, K/Ca, Sr/Ca and Mn/S ratios were constructed and correlated with precipitation, temperature, the difference between precipitation and potential evapotranspiration (P-PET) and standardized precipitation–evapotranspiration index (SPEI).ResultsDuring dry years, C. fissilis showed narrower, less dense rings, lower Al, P, S and Ca, and higher K and Fe concentrations (the opposite was found in wet years). Ring width decreased (together with Al, P, S, K, Ca, Mn, Fe, Sr, Al/Ca, K/Ca and Sr/Ca) and wood density increased (together with Ca/Mn and Mn/S), which was associated with an increase in evapotranspiration and temperature over time, mainly since 1990. Cedrela fissilis showed a tendency to increase its capacity for resistance, and a recovery and resilience in growth over time associated with responses in Al, Ca, P and S. However, it showed a risk in the capacity for recovery of the pre-drought density values, associated with unsatisfactory responses in Al, Ca, K, Fe and P.ConclusionsThis study is the first attempt to analyze tree-ring nutritional evidences of C. fissilis trees to climate sensitivity and resilience to drought, based on long-term data from seasonal moist tropical forests of the Amazon. Our data suggested that C. fissilis is undergoing alterations in the concentration, use and redistribution of nutrients associated with increasing wood density and decreasing growth over time, due to the increase of drought frequency in the southern Amazon.

Long- and short-term impacts of climate and dry-season on wood traits of Cedrela fissilis Vell. in southern Brazilian Amazon

Long- and short-term impacts of climate and dry-season on wood traits of Cedrela fissilis Vell. in southern Brazilian Amazon

Climate variability of the southern Amazon inferred by a multi-proxy tree-ring approach using Cedrela fissilis Vell.

The analysis of climate variability and development of reconstructions based on tree-ring records in tropical forests have been increasing in recent decades. In the Amazon region, ring width and stable isotope long-term chronologies have been used for climatic studies, however little is known about the potential of wood traits such as density and chemical concentrations. In this study, we used well-dated rings of Cedrela fissilis Vell. from the drought-prone southern Amazon basin to assess the potential of using inter-annual variations of annually-resolved ring width, wood density, stable oxygen isotope (δ18OTR) measured in tree-ring cellulose and concentration of Sulfur (STR) and Calcium (CaTR) in xylem cells to study climate variability. During wet years, Cedrela fissilis produced wider and denser rings with higher CaTR and lower STR, as well as depleted δ18OTR values. During dry years, a wider range of responses was observed in growth, density and STR, while lower CaTR and enriched δ18OTR values were found. The annual centennial chronologies spanning from 1835 to 2018 showed good calibration skills for reconstructing local precipitation, evapotranspiration (P-PET), Amazon-wide rainfall, as well as climate modes related to sea surface temperature (SST) anomalies such as El Niño South Oscillation (ENSO), Tropical Northern Atlantic (TNA), and the Western Hemisphere Warm Pool (WHWP) oscillations. CaTR explained 42 % of the variance of local precipitation (1975–2018), RW explained 30 % of the P-PET variance (1975–2018), while δ18OTR explained 60 % and 57 % of the variance of Amazon rainfall (1960–2018) and El Niño 3.4 (1920–2018), respectively. Our results show that a multi-proxy tropical tree-ring approach can be used for high-reliable reconstructions of climate variability over Amazon basin at inter-annual and multidecadal time scales.

Morphology of pollen grains and orbicules of two threatened species of Cedrela P. Browne (Meliaceae A. Juss.).

Pollen grain morphology and the characterization of additional structures related to pollen dispersion can help to understand the strategies presented by species as well as their taxonomic circumscription. This work investigates the morphology of pollen grains and orbicules of Cedrela fissilis Vell. and Cedrela odorata L., two threatened species of the genus Cedrela P. Browne (Meliaceae A. Juss.) in Brazil. Observations of pollen grains and orbicules of the species were carried out pre- and post-chemical treatment of the samples, under light and scanning electron microscopy, aiming at recognizing structures, detailing morphological characterizations and taking measurements, the last of which were submitted to statistical treatment. The results demonstrate that the pollen grains of the two species are medium in size (measuring between 25 and 50µm), radially symmetrical, isopolar, prolate-spheroidal and 4,5-colporate with subcircular to subquadrangular amb and psilate ornamentation; the orbicules also have a smooth surface and measure about 7 to 10µm. Variation was observed in the size of pollen grains, which presented high coefficient of variation and in the orbicules, as well as in the number of apertures.

Seedlings of Cedrela fissilis Vell. respond to single superphosphate application, but not to liming

Seedlings of Cedrela fissilis Vell. respond to single superphosphate application, but not to liming

Composted sewage sludge as an alternative substrate for forest seedlings production

The production of forest seedlings with adequate morphological and physiological characteristics is essential for the success of plantations. Substrates and irrigation are the major factors determining seedlings’ growth. Substrates made of urban and agricultural residues are a sustainable alternative to peat-based substrates. In this study, we evaluated how composted sewage sludge substrates affect the growth and gas exchange in seedlings of Cedrela fissilis Vell. Seedlings were produced under daily irrigation depths of 6, 9, and 12 mm, and on different substrates. The substrates were based on sewage sludge composted with Eucalyptus bark or sugarcane bagasse, and a commercial substrate based on peat, involving a double factorial design with 12 treatments (3 irrigation depths × 3 substrates). Both physical and chemical characteristics of substrates were analyzed, and morphological traits and gas exchanges of seedlings were measured. Sewage sludge-based substrates presented different characteristics according to the material it was mixed. Eucalyptus bark provided higher bulk density (0.19 g cm-3) and lower total porosity (75%) to the substrate, while sugarcane bagasse increased macroporosity up to 60%. Seedlings produced in sewage sludge-based substrates presented a height up to 17.8 cm and stem diameters of between 8.39-10.29 mm. Higher shoot and root dry mass was obtained in sewage sludge-based substrates with irrigation depth of 9 mm, which were 3.71 and 2.01 g, respectively. Photosynthetic carbon assimilation varied between 2.26 and 3.23 µmol CO2 m-2 s-1, and water use efficiency varied from 2.058 to 3.395 µmol CO2 (mol H2O)-1, with the highest values being obtained in seedlings produced in sewage sludge-based substrates with irrigation depth of 6 mm. Our results demonstrate that sewage sludge-based substrates are an efficient alternative to commercial peat-based substrates for seedling production.

Growth ring response of two Atlantic Forest tree species pre- and post-dam operation in Southern Brazil

Hydropower plants are important sources of renewable energy, but the climatic impacts of their constructions remain poorly explored. Considering that tree growth analysis is a useful tool to identify environmental impacts, this study aimed at using climate records and tree-ring chronologies to understand possible local climate changes caused by the construction of a hydropower plant in the 1980s in the State of Paraná, Southern Brazil. Historical climatic data were obtained from the local meteorological station and surrounding municipalities and analyzed using ANOVA and means tests. The Pettitt test was additionally used to identify change-points in the meteorological data. Wood samples from a total of 60 trees from Araucaria angustifolia (Bertol.) Kuntze (Araucariaceae) and Cedrela fissilis Vell. (Meliaceae) were collected, and tree-ring chronologies were built using dendrochronological standard procedures. Chronologies for A. angustifolia and C. fissilis represented time periods from 1800 to 2016 and 1899–2015, respectively. Tree-ring growth responses to climatic variables were evaluated by adjusting generalized mixed linear models and the Spearman correlations. Our results evidenced that the hydropower plant altered the local climate, mostly influencing the hydrological cycle by increasing local rainfall, with monthly rain volumes being statistically higher than in other meteorological stations. Significant responses in the growth of A. angustifolia were found to be associated with the water level increase caused by the dam and of C. fissilis due to the increase in cloud cover.

Long-term subculture affects rooting competence via changes in the hormones and protein profiles in Cedrela fissilis Vell. (Meliaceae) shoots

Long-term subculture plays an essential role in the large-scale multiplication and production of somatic plantlets. We investigated the effects of long-term subculture on in vitro shoot development and ex vitro rooting associated with changes in the hormones and protein profiles in Cedrela fissilis. The number of subcultures of shoots induced a decrease in the ex vitro rooting response. The reduction in adventitious root (AR) formation was associated with decreases in the contents of indole-3-acetic acid (IAA), abscisic acid (ABA), 12-oxo-phytodienoic acid (OPDA), putrescine (Put), and spermine and increases in jasmonic acid (JA), jasmonoyl-isoleucine, trans-cinnamic acid, and salicylic acid contents in shoots at the fourth subculture compared to the first. The ornithine decarboxylase enzyme preferentially functions in the Put biosynthesis pathway, and it was related to the highest AR formation in shoots at the first subculture. Down-accumulation of the auxin-binding protein ABP19a in shoots from the fourth subculture compared to the first subculture was related to a decrease in both the IAA content and AR formation. In addition, down-accumulation of glucose-6-phosphate isomerase; glutamine synthetase leaf isozyme, chloroplastic; 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase; l-ascorbate peroxidase, cytosolic; monodehydroascorbate reductase; and 2-Cys peroxiredoxin BAS1-like, chloroplastic and up-accumulation of caffeoyl-CoA O-methyltransferase 1 and isoforms of peroxidase 4 proteins in shoots from the fourth relative to the first subculture were associated with a reduction in AR formation. These results showed that the understanding of hormonal and molecular mechanisms related to the potential of AR formation in shoots under successive subcultures is relevant to improving large-scale plantlet production in C. fissilis.

Growth Assessment of Native Tree Species from the Southwestern Brazilian Amazonia by Post-AD 1950 14C Analysis: Implications for Tropical Dendroclimatology Studies and Atmospheric 14C Reconstructions

Tree-ring width chronologies of cedro (Cedrela fissilis Vell.) (1875 to 2018), jatobá (Hymenaea courbaril L.) (1840 to 2018) and roxinho Peltogyne paniculata Benth.) (1910 to 2018) were developed by dendrochronological techniques in the southern Amazon Basin. Acceptable statistics for the tree-ring chronologies were obtained, and annual calendar dates were assigned. Due to the lack of long-term chronologies for use in paleoclimate reconstructions in degraded forest areas, dendrochronological dating was validated by 14C analysis. Tree-rings selected for analysis corresponded to 1957, 1958, 1962, 1963, 1965, 1971, and 1972. Those are critical calendar years in which atmospheric 14C changes were the highest, and therefore their tree-ring cellulose extracts 14C signatures when in alignment with existing post-AD 1950 atmospheric 14C atmospheric curves would indicate annual periodicity. Throughout our correlated calendar years and post-AD 1950 14C signatures, we indicate that H. courbaril shows an erratic sequence of wood ages. The other two tree species, C. fissilis and P. paniculata, are annual in nature and can be used successfully as paleoclimate proxies. Moreover, due to the sampling site’s strategic location in relation to the Tropical Low-Pressure Belt over South America, these trees can be used to enhance the limited amount of observational data in Southern Hemisphere atmospheric 14C calibration curves.

Ecophysiological Strategies of Cedrela fissilis Vell. Seedlings under Conditions of Flooding and Light Availability

ABSTRACT Soil water availability and light are abiotic factors that may be plant stressors when they are subjected to unfavorable conditions and may limit their metabolism and trigger protection mechanisms. The aim of this study was to evaluate morphological and metabolic strategies in Cedrela fissilis seedlings that enable their survival and resilience when subjected to flooding and shading. The seedlings were cultivated under flooding for 0, 10, 20, 30, and 40 days or received only rainwater (control: 120 mm distributed over 35 evaluation days with a daily maximum of 28 mm). Flooding treatments were conducted under 70%, 30%, and 0% shading. Cedrela fissilis seedlings presented plasticity in physiological and morphological responses to flooding and shading, which indicates that this species has the potential for survival in the evaluated environments. The seedlings were tolerant to flooding for up to 40 days, regardless of light availability, although 70% shading minimized the stressful effects of flooding. The formation of lenticels, adventitious roots, and the increased activity of antioxidant enzymes from the 20th day of flooding favored the resilience of photosynthetic metabolism.

In vitro multiplication of Cedrela fissilis Vell.: A threatened brazilian hardwood forest tree

Cedrela fissilis Vell. is a valuable wood species from Atlantic Forest and is at risk of extinction. Therefore, a protocol for plant regeneration was developed for C. fissilis using different explants from in vitro germinated plant. The seeds were germinated in total or half- strength MS and B5 basal. The half-strength MS medium was chosen because of its uniform morphological aspect, highgermination rate (82) and germination speed index (1.218). The shoot tips, nodal segments and cotyledonary nodes explants were extracted from the germinated in vitro plants and cultivated for shoot induction in MS medium supplemented with KIN or BAP (0, 0.5, 2, 4 μM). Among the different explants, cytokinins and concentrations, the highest number (2.2) and length (3.84 cm) of shoots were induced in cotyledonary nodes without cytokinin. For rooting of shoot regenerated from explants, the MS medium was supplemented with IBA or NAA (0, 1, 3 μM). Rooting was induced in all auxins type and concentrations, with higher number of roots per explant with 3μM IBA (2.54). In conclusion, the present study provides in vitro shoot and root regeneration system in C. fissilis without plant growth regulators and great potential in micropropagation, germplasm preservation and genetic transformation. Index terms: Cedro-rosa; vulnerable; cotyledonary nodes; plant growth regulator; micropropagation.

Nonlinear models in the study of the cedar diametric growth in a seasonally dry tropical forest

The continuous decrease of forest cover in Brazil and the growing environmental pressure on forest-originate products increase the concern with the protection of the native forests remnants and endangered species such as the cedar (Cedrela fissilis Vell.), which has great economic prominence in the country due to the its excellent wood quality. Therefore, studying in detail its growth as a basis for its sustainable management in the forests is necessary. Based on the knowledge that nonlinear models are traditionally well fit for biological processes, this study aimed to compare the performance of the Brody, Gompertz, Logistic and von Bertalanffy models in reconstructing the cedar diametric growth. To that end, we used data from the mean diameter at breast height accumulated over time, obtained from non-destructive samples of 85 trees in an environmental preservation area. The models were fit using the R software considering the autoregressive error structure as of first order. All models demonstrated a good fit, although the Brody model was the best to describe the diametric growth of cedar over time in the studied region.

Atopozelus opsimus (Hemiptera: Reduviidae) Preying on Mastigimas anjosi (Hemiptera: Calophyidae), a Pest of Tropical Cedar, Cedrela fissilis (Meliaceae)

Insects pests such as Mastigimas anjosi Burckhardt (Hemiptera: Calophyidae), native to Brazil, limit the establishment of commercial plantations of the tropical cedar Cedrela fissilis Vell. (Meliaceae), reducing growth and affecting tree shape. Insecticides have been used to suppress M. anjosi outbreaks, but sustainable alternatives should be developed to manage this pest. The objective of this work was to report, for the first time, the predator Atopozelus opsimus Elkins (Hemiptera: Reduviidae) preying on M. anjosi attacking C. fissilis trees in Minas Gerais State, Brazil. Trees of this plant were observed between Apr and May 2018 in Montes Claros, Minas Gerais State, Brazil. Atopozelus opsimus adults preyed on M. anjosi nymphs and adults, and fed on their honeydew. This predator did not eliminate the damage to C. fissilis, which may be related to the temperatures of the region, and which may have affected reproduction and increased its development period. Sumario Insetos pragas, como Mastigimas anjosi Burckhardt (Hemiptera: Calophyidae), nativo do Brasil, limitam o estabelecimento de plantios comerciais de Cedrela fissilis Vell. (Meliaceae), reduzindo o crescimento e afetando a forma das arvores. Inseticidas tem sido usados para suprimir surtos de M. anjosi, mas alternativas sustentaveis devem ser desenvolvidas para manejar essa praga. O objetivo desse trabalho foi relatar, pela primeira vez, o predador Atopozelus opsimus Elkins (Hemiptera: Reduviidae) predando M. anjosi atacando arvores de C. fissilis no estado de Minas Gerais, Brasil. Arvores dessa planta foram observadas entre abril e maio de 2018 em Montes Claros, estado de Minas Gerais, Brasil. Adultos de A. opsimus predaram ninfas e adultos de M. anjosi, e se alimentaram de honeydew. Esse predador nao eliminou os danos em C. fissilis, o que pode estar relacionado as temperaturas da regiao, que podem ter afetado sua reproducao e aumentado seu periodo de desenvolvimento. Key Words: biological control; bug; honeydew; predation, tropical cedar View this article in BioOne https://doi.org/10.1653/024.102.0227

The Effects of Habitat Loss on Genetic Diversity and Population Structure of Cedrela fissilis Vell.

Cedrela fissilis Vell. has a wide distribution in South and Central America, and in neotropical forests the species occurs at a low density. Its wood is one of the most valued around the world, and the species is currently at risk of extinction due to both habitat fragmentation and illegal logging. Considering the need for conservation strategies, this study aims to investigate the genetic structure, diversity, and inbreeding in C. fissilis populations from the Atlantic Forest. To do this, nine microsatellite loci were used to genotype 289 individuals from eight undisturbed and disturbed fragments. Two of the eight populations harbor most of the genetic diversity: one includes most of the diversity present in all populations and the other is isolated but with high levels of diversity. Genetic diversity was higher within than among populations, with observed and expected heterozygosities ranging from 0.48 to 0.63 and from 0.55 to 0.70, respectively. We detected a significant fixation index, ranging from 0.08 to 0.24 and 32% of the observed alleles were exclusive of some population. The populations showed moderate genetic structure (FST = 0.10) and the Bayesian analysis grouped the studied individuals into three distinct genetic clusters that seem to be related to the presence of geographical barriers. The overall analyses of the results allow us to conclude that protecting only isolated fragments, either large or small, may be ineffective for conserving the C. fissilis gene pool in the studied region. This observation suggests that an appropriate strategy to conserve the gene pool of the species is to maintain both the Atlantic Forest green belt in the eastern portion of the Central and South region of this biome, where the forest is not highly fragmented, as well as the remaining forest areas to the west of the Parana River.

In situ DNA fragmentation during the re-establishment of desiccation tolerance in germinated seeds of Cedrela fissilis Vell.

Abstract: Dehydration is a necessary procedure prior to exposing seeds to long term storage, but this is associated with metabolism-linked injury mediated by cell injury. In order to assess cellular alterations during re-establishment of desiccation tolerance (DT) in C. fissilis germinated seeds and their relation to DNA damage, we verified the occurrence of DNA fragmentation through the TUNEL test and its evidence through the cytological analyses. To re-establish DT, germinated seeds were incubated for 72 h in polyethylene glycol (PEG, -2.04 MPa) before dehydration in silica gel (at 10% moisture content) followed by rehydration. The moisture content changes during the reestablishment of the desiccation tolerance was accomplished. (DT)TdT-dUPT terminal nick-end labeling (TUNEL) was used to assess rates of cell death. TUNEL staining was performed using Click-iT-TUNEL Alexa Flour imaging assay. The TUNEL test showed a consistent DNA fragmentation in the 2 and 5 mm long radicles. Moreover, nuclear and chromosomal alterations were observed in the 5 mm meristematic root cell cycle, contributing to the identification of diagnostic markers of cell death.

Influence of forest gaps on the density of cedar population in Silveira Martins-RS

The objective of this study is to analyze the influence of gaps on the density of cedar population ( Cedrela fissilis Vell.) and characterize the total diameter distribution and size class of this species. The study area is located in the municipality of Silveira Martins (state of Rio Grande do Sul), where a census was conducted by walking through 5.54 hectares. The area was divided and characterized into A (0.36 ha), more intensive use of soil; B (0.10 ha), gap with a radius of approximately 17.5 m; C (0.08 ha), gap with radius of approximately 16 m; and D (5.0 ha), intermediate regeneration. All cedar individuals with a total height greater than 15 cm were measured and classified as adults (diameter at breast height - DBH > 10 cm), young (0 < DBH <10 cm), and seedlings (total height - Ht < 1.30 m). The density per area and the Chi-square test for the different areas were calculated. In addi­tion, a diameter distribution histogram was constructed for each size class and area. The negative exponential shape of diametric distribution histograms evidences that the areas with gaps present a higher frequency of young individuals and seedlings; however, there was no difference between the gaps (areas B and C) and the area at an initial regeneration stage (area D).

TOLERÂNCIA DE PLÂNTULAS DE &lt;i&gt;Cedrela fissilis&lt;/i&gt; VELL. A DIFERENTES AMPLITUDES E INTENSIDADES DE INUNDAÇÃO

A presença de água no solo, tanto em regime temporário quanto permanente, exige diferentes estratégias adaptativas das espécies vegetais que ocupam estas áreas. Neste sentido, investigamos as respostas morfológicas e de alocação de biomassa em plântulas de Cedrela fissilis Vell. (Meliaceae) submetidas a diferentes amplitudes e intensidades de inundação. Plântulas de Cedrela fissilis foram submetidas a duas intensidades de inundação (submersão ao nível de coleto e total) em três diferentes amplitudes (cinco, 15 e 20 dias) e após 30, 60 e 90 dias de recuperação da condição de inundação foram realizadas avaliações da altura da parte aérea, número de folhas, diâmetro do colo e índices de clorofila a, b e, total. Após 90 dias de recuperação, a altura total, diâmetro da raiz, comprimento da raiz, biomassa total, área foliar e o crescimento das raízes foram avaliados. Plântulas não inundadas constituíram um grupo controle. As plântulas submetidas à inundação total não sobreviveram. Por outro lado, as plântulas sob inundação parcial recuperaram a taxa de crescimento ao longo dos 90 dias de recuperação da inundação. Não foram observadas diferenças nas variáveis de crescimento e alocação de biomassa em relação às plântulas-controle. Todavia, observou-se que durante o período de recuperação, as plântulas submetidas a 20 dias de inundação parcial apresentaram maior taxa de abscisão foliar acompanhado por um aumento nos índices de clorofila a e b. Os resultados indicaram que esta espécie apresenta tolerância à intensidade de inundação parcial, devendo ser cuidadosamente selecionada quanto às áreas de plantio.

Morpho-physiological responses in Cedrela fissilis Vell. submitted to changes in natural light conditions: implications for biomass accumulation

The initial photoinhibition observed when Cedrela fissilis was transferred from shade to full sunlight was not severe enough to affect their biomass accumulation. We investigated the growth and, morphological and physiological changes in Cedrela fissilis, a tropical tree species known for its high-quality wood, when subjected to changes in natural light conditions. We assessed the magnitude of photoinhibition when plants that were acclimated to shade were transferred into full sunlight and also assessed the impact of probable photoinhibition on the leaf morphology and growth of C. fissilis. We cultivated plants under three conditions: beneath the canopy (shade), under full sunlight, and transferring shade plants to full sunlight. During the period of the experiment (7 months), C. fissilis had 100 % survival in all treatments including shade conditions which corresponded to 1 % of light available compared to full sunlight. The growth was reduced under the shade, but the specific leaf area and biomass allocated to leaves were higher. After the change from shade to full sunlight conditions, reductions in potential photochemical yield (F v/F m) were detected in both predawn and midday measurements, characterizing the occurrence of photoinhibition. However, 30 days after the transfer, the mean value of F v/F m for those plants was 0.79, similar to that reached by plants permanently under full sunlight or shade conditions. The recovery of photoinhibition was followed by increases in the electron transport rates. Among the transferred plants, alterations in leaf structure and a shift in biomass partitioning patterns were observed. The photoinhibition that was detected early in the experiment was not severe enough to impact the relative growth rate and biomass accumulation. Our results show that C. fissilis can grow under the shade or full sunlight. However, when shade plants were transferred to full sunlight, they reached an efficient acclimation to the new environment through physiological alterations in their leaves and morphological modifications in the whole plant.

Polyamine, amino acid, and carbohydrate profiles during seed storage of threatened woody species of the Brazilian Atlantic Forest may be associated with seed viability maintenance

Due to the economic importance of wood production, species including Cedrela fissilis Vell. and Cariniana legalis (Mart.) Kuntze have been heavily exploited and are currently threatened with extinction. In addition, these species produce seeds with low viability when stored for long periods. In this work, the effect of storage time on seedling emergence and alterations in the levels of biomolecules such as carbohydrates, polyamines (PAs), and amino acids were analyzed in C. fissilis and C. legalis seeds. Seedling emergence and the emergence speed index were significantly reduced during seed storage in both species, with a greater reduction for C. legalis seeds. Sucrose was detected in both species, with the highest levels in C. fissilis seeds, whereas the monosaccharides glucose and fructose were detected only in C. legalis seeds. Higher levels of putrescine (Put) were observed in C. legalis seeds than in C. fissilis seeds. In contrast, C. fissilis seeds showed a significant increase in most of the amino acids analyzed. These results suggest that the presence of glucose and fructose, the higher level of Put, and the lower levels of amino acids observed in C. legalis seeds may be associated with greater reductions in vigor and seedling emergence compared with C. fissilis seeds. This is the first report showing these relationships among carbohydrates, PAs, and amino acids in these species and may be useful for further studies on seed conservation of timber species.