Long-term seedling and small sapling census data from the Barro Colorado Island 50 ha Forest Dynamics Plot, Panama.

Tropical forests are well known for their high woody plant diversity. Processes occurring at early life stages are thought to play a critical role in maintaining this high diversity and shaping the composition of tropical tree communities. To evaluate hypothesized mechanisms promoting tropical tree species coexistence and influencing composition, we initiated a census of woody seedlings and small saplings in the permanent 50 ha Forest Dynamics Plot (FDP) on Barro Colorado Island (BCI), Panama. Situated in old-growth, lowland tropical moist forest, the BCI FDP was originally established in 1980 to monitor trees and shrubs ≥1 cm diameter at 1.3 m above ground (dbh) at ca. 5-year intervals. However, critical data on the dynamics occurring at earlier life stages were initially lacking. Therefore, in 2001 we established a 1-m2 seedling plot in the center of every 5 × 5 m section of the BCI FDP. All freestanding woody individuals ≥20 cm tall and <1 cm dbh (hereafter referred to as seedlings) were tagged, mapped, measured, and identified to species in 19,313 1-m2 seedling plots. Because seedling dynamics are rapid, we censused these seedling plots every 1-2 years. Here, we present data from the 14 censuses of these seedling plots conducted between the initial census in 2001 to the most recent census, in 2018. This data set includes nearly 1 M observations of ~185,000 individuals of >400 tree, shrub, and liana species. These data will permit spatially-explicit analyses of seedling distributions, recruitment, growth, and survival for hundreds of woody plant species. In addition, the data presented here can be linked to openly-available, long-term data on the dynamics of trees and shrubs ≥1 cm dbh in the BCI FDP, as well as existing data sets from the site on climate, canopy structure, phylogenetic relatedness, functional traits, soil nutrients, and topography. This data set can be freely used for non-commercial purposes; we request that users of these data cite this data paper in all publications resulting from the use of this data set.

Schinus Essential Oils: Chemical Composition by GC×GC-TOFMS and Phytotoxic Effects on Arabidopsis thaliana.

Schinus essential oils were tentatively identified by GC×GC/TOFMS, which revealed a greater number of compounds than previously reported. Eighty-six, seventy-two, and eighty-eight components were identified in Schinus lentiscifolius, Schinus molle and Schinus terebinthifolius essential oils, respectively. Compound separation due to 2 D selectivity was observed. Phytotoxic effects of Schinus essential oils were assessed on germination and initial growth of Arabidopsis thaliana. All essential oils in all tested quantities (5 µL, 10 µL, 15 µL, 20 µL, and 25 µL) affected germination rate, speed of accumulated germination, and root and shoot length of A. thaliana. Considering the mode of action of the essential oils, no differences were observed on expression of the genes ANP1 and CDK B1;1 in A. thaliana, which was analyzed by RT-qPCR. Results suggest that phytotoxic effects of Schinus essential oils seem to be explained by cellular damage rather than by induction of stress-inducible genes.

Constraints on tree seedling establishment after fires: passing the germination bottlenecks.

Persistence and colonization by tree species in an environment following a fire depends on the effects on seed germination and seedling development. We used seeds of Kielmeyera coriacea and Qualea parviflora as a model to test the effects of high temperatures on germination and initial development of tree seedlings. We exposed the seeds to heat flow (70, 100, 130, 150 or 170 °C) for 2 or 5 min and compared the germination with that of unheated seeds (control). Seedlings were then harvested after 3, 7 or 15 days to evaluate aerial and root mass, root:shoot ratio, presence of cotyledon opening, true leaves, and secondary roots. We found no effect on germination for seeds exposed to temperatures ≥150 °C. However, germination was significantly reduced for seeds exposed to 100 °C for both 2 and 5 min. The mass of 15-day-old K. coriacea seedlings was smaller when seeds were heated at 70 °C for 5 min or at temperatures higher or equal to 100 °C. Qualea parviflora seedlings did not show any difference in mass, but there were marginal differences in the presence of roots and the opening of cotyledons. Kielmeyera coriacea seedlings allocated biomass faster than Q. parviflora. High temperatures affect both quantity and quality of germinable seeds, as well as biomass allocation during initial seedling development. These factors may explain the decrease in seedlings observed after fire, suggesting a bottleneck effect that influences population dynamics and species persistence in systems with frequent fires.

Invasive trees rely more on mycorrhizas, countering the ideal-weed hypothesis.

The ideal-weed hypothesis predicts that invasive plants should be less dependent on mutualisms. However, evidence in favor of or against this hypothesis comes mainly from observational studies. Here, we experimentally tested this hypothesis using a two-factor greenhouse experiment, comparing the seedling growth response of different Pinus species (varying in invasiveness) to ectomycorrhizal fungal inoculation. Most species showed no response until they were 6 mo old, at which point inoculation increased growth between 10 and 260% among the different species. This growth response was higher for species with lower seed mass, higher dispersal ability, higher Z score (a proxy for invasiveness) and higher number of naturalized regions, all of which correspond to higher invasiveness. Our results show that timing is a crucial factor when comparing mycorrhizal dependency of different species. Dependence on mutualistic microorganisms could be part of a strategy in which invasive species produce smaller seeds, in greater number, which can disperse further, but where seedlings are more reliant on mycorrhizas to improve access to water, nutrients, and protection from pathogens. Our results suggest that reliance on mutualisms may enhance, rather than limit, nonnative species in their ability to spread, establish, and colonize.

Seedling length and soybean seed vigor / Comprimento de plântulas e vigor de sementes de soja

The differentiation of seedling growth and development is the result of the vigor level of the seed lot. Because of this, knowing the seedling growth curve is essential for the evaluation of the seedling length test, to be carried out at the moment when any differences in vigor really manifest, thus being able to reduce the time of evaluation of the test. In this research, the objective was to determine the most efficient time interval to perform the seedling length test in soybean seeds, depending on the vigor levels. The evaluated characteristics were percentage of seed germination, first germination count, emergency, days for emergence, aerial, root and total length (evaluated every 12 hours), aerial, root and total dry mass in completely randomized design. High vigor seeds originated seedlings with higher growth rates (cm. h-1), with vigor being one of the factors that interfere in the seedling length test. After 96 hours of the seedling length test, there was a statistical differentiation between the three vigor levels tested. The soybean seedling length test between lots, with different vigor, can be performed 96 hours after sowing.(AU)

A diferenciação do crescimento e desenvolvimento das plântulas, é resultado do nível de vigor do lote das sementes. Em virtude disto, conhecer a curva de crescimento das plântulas é fundamental para que a avaliação do teste de comprimento de plântulas, seja realizada no momento em que realmente se manifestem as eventuais diferenças de vigor, podendo assim reduzir o tempo de avaliação do teste. No trabalho, o objetivo foi determinar o intervalo de tempo mais eficiente para realizar o teste de comprimento de plântula em sementes de soja, em função dos níveis de vigor. As características avaliadas foram germinação, primeira contagem de germinação, emergência, dias para emergência, comprimento de parte aérea, raiz e total (avaliados de 12 em 12 horas), massa seca de parte aérea, raiz e total em delineamento inteiramente casualizado. As sementes de alto vigor originaram plântulas com maiores taxas de crescimento (cm. h-1), sendo o vigor um dos fatores que interfere no teste de comprimento de plântulas. Após 96 horas do teste de comprimento de plântula ocorreu a diferenciação estatística entre os três níveis de vigor testados. O teste de comprimento de plântula de soja entre lotes, com vigor distinto, pode ser realizado 96 horas após a semeadura.(AU)

Seedling length and soybean seed vigor / Comprimento de plântulas e vigor de sementes de soja

ABSTRACT: The differentiation of seedling growth and development is the result of the vigor level of the seed lot. Because of this, knowing the seedling growth curve is essential for the evaluation of the seedling length test, to be carried out at the moment when any differences in vigor really manifest, thus being able to reduce the time of evaluation of the test. In this research, the objective was to determine the most efficient time interval to perform the seedling length test in soybean seeds, depending on the vigor levels. The evaluated characteristics were percentage of seed germination, first germination count, emergency, days for emergence, aerial, root and total length (evaluated every 12 hours), aerial, root and total dry mass in completely randomized design. High vigor seeds originated seedlings with higher growth rates (cm. h-1), with vigor being one of the factors that interfere in the seedling length test. After 96 hours of the seedling length test, there was a statistical differentiation between the three vigor levels tested. The soybean seedling length test between lots, with different vigor, can be performed 96 hours after sowing.

RESUMO: A diferenciação do crescimento e desenvolvimento das plântulas, é resultado do nível de vigor do lote das sementes. Em virtude disto, conhecer a curva de crescimento das plântulas é fundamental para que a avaliação do teste de comprimento de plântulas, seja realizada no momento em que realmente se manifestem as eventuais diferenças de vigor, podendo assim reduzir o tempo de avaliação do teste. No trabalho, o objetivo foi determinar o intervalo de tempo mais eficiente para realizar o teste de comprimento de plântula em sementes de soja, em função dos níveis de vigor. As características avaliadas foram germinação, primeira contagem de germinação, emergência, dias para emergência, comprimento de parte aérea, raiz e total (avaliados de 12 em 12 horas), massa seca de parte aérea, raiz e total em delineamento inteiramente casualizado. As sementes de alto vigor originaram plântulas com maiores taxas de crescimento (cm. h-1), sendo o vigor um dos fatores que interfere no teste de comprimento de plântulas. Após 96 horas do teste de comprimento de plântula ocorreu a diferenciação estatística entre os três níveis de vigor testados. O teste de comprimento de plântula de soja entre lotes, com vigor distinto, pode ser realizado 96 horas após a semeadura.

Salicylic acid and its method of application affect germination and vigor in bell pepper seedlings under salt stress / Ácido salicílico e sua forma de aplicação alteram a germinação e o vigor de plântulas de pimentão sob estresse salino

This study investigated the effect of two salicylic acid application methods (seed immersion and wetting) on the germination and growth characteristics of cv. All Big bell pepper seedlings exposed to 0 or 100 mM of NaCl. The experiment was conducted in a Biochemical Oxygen Demand (BOD) incubator, using a completely randomized design with eight treatments (immersion in salicylic acid or distilled water and wetting with salicylic acid or water, in conjunction with 0 or 100 mM of NaCl) and four repetitions. The results indicated that under non-saline conditions, wetting with salicylic acid (SA) inhibited germination and seedling length, whereas NaCl stress reduced the germination, growth, total dry weight and vigor of seedlings. However, SA application, especially by wetting, mitigated the toxic effects of NaCl in bell pepper seedlings, improving relative water content and radicle length, as well as total length, dry weight and vigor. This study highlights the potential benefits of SA, particularly when applied via wetting, in attenuating phytotoxicity caused by NaCl stress and its effect on the germination, growth and vigor of bell pepper seedlings.(AU)

Os efeitos do ácido salicílico em duas formas de aplicação (imersão ou umedecimento das sementes) foram investigados nas características de germinação e crescimento de plântulas de pimentão cv. All Big sob 0 ou 100 mM de NaCl. Um experimento em câmara de germinação foi realizado em delineamento inteiramente casualizado com oito tratamentos (imersão das sementes em AS ou água destilada e umedecimento com AS ou água, associados às concentrações de 0 ou 100 mM de NaCl), cada um com quatro repetições. Os resultados indicaram que em condição não salina, o AS no umedecimento inibiu a germinação e o comprimento da plântula, enquanto o estresse de NaCl reduziu a germinação, o crescimento, a produção total de massa seca e o índice de vigor das plântulas. No entanto, a aplicação de AS, sobretudo no umedecimento atenuou os efeitos tóxicos do NaCl nas plântulas de pimentão melhorando o conteúdo relativo de água, o comprimento da radícula, bem como o comprimento e massa seca total e índice de vigor das plântulas. Este estudo destaca potenciais efeitos benéficos de AS, principalmente aplicado no umedecimento, na atenuação da fitotoxicidade do estresse de NaCl sobre a germinação, crescimento e vigor de plântulas de pimentão.(AU)

Salicylic acid and its method of application affect germination and vigor in bell pepper seedlings under salt stress / Ácido salicílico e sua forma de aplicação alteram a germinação e o vigor de plântulas de pimentão sob estresse salino

This study investigated the effect of two salicylic acid application methods (seed immersion and wetting) on the germination and growth characteristics of cv. All Big bell pepper seedlings exposed to 0 or 100 mM of NaCl. The experiment was conducted in a Biochemical Oxygen Demand (BOD) incubator, using a completely randomized design with eight treatments (immersion in salicylic acid or distilled water and wetting with salicylic acid or water, in conjunction with 0 or 100 mM of NaCl) and four repetitions. The results indicated that under non-saline conditions, wetting with salicylic acid (SA) inhibited germination and seedling length, whereas NaCl stress reduced the germination, growth, total dry weight and vigor of seedlings. However, SA application, especially by wetting, mitigated the toxic effects of NaCl in bell pepper seedlings, improving relative water content and radicle length, as well as total length, dry weight and vigor. This study highlights the potential benefits of SA, particularly when applied via wetting, in attenuating phytotoxicity caused by NaCl stress and its effect on the germination, growth and vigor of bell pepper seedlings.

Os efeitos do ácido salicílico em duas formas de aplicação (imersão ou umedecimento das sementes) foram investigados nas características de germinação e crescimento de plântulas de pimentão cv. All Big sob 0 ou 100 mM de NaCl. Um experimento em câmara de germinação foi realizado em delineamento inteiramente casualizado com oito tratamentos (imersão das sementes em AS ou água destilada e umedecimento com AS ou água, associados às concentrações de 0 ou 100 mM de NaCl), cada um com quatro repetições. Os resultados indicaram que em condição não salina, o AS no umedecimento inibiu a germinação e o comprimento da plântula, enquanto o estresse de NaCl reduziu a germinação, o crescimento, a produção total de massa seca e o índice de vigor das plântulas. No entanto, a aplicação de AS, sobretudo no umedecimento atenuou os efeitos tóxicos do NaCl nas plântulas de pimentão melhorando o conteúdo relativo de água, o comprimento da radícula, bem como o comprimento e massa seca total e índice de vigor das plântulas. Este estudo destaca potenciais efeitos benéficos de AS, principalmente aplicado no umedecimento, na atenuação da fitotoxicidade do estresse de NaCl sobre a germinação, crescimento e vigor de plântulas de pimentão.

Highly invasive tree species are more dependent on mutualisms.

Why some species become invasive while others do not remains an elusive question. It has been proposed that invasive species should depend less on mutualisms, because their spread would then be less constrained by the availability of mutualistic partners. We tested this idea with the genus Pinus, whose degree of invasiveness is known at the species level (being highly and negatively correlated with seed size), and which forms obligate mutualistic associations with ectomycorrhizal fungi (EMF). Mycorrhizal dependence is defined as the degree to which a plant needs the mycorrhizal fungi to show the maximum growth. In this regard, we use plant growth response to mycorrhizal fungi as a proxy for mycorrhizal dependence. We assessed the responsiveness of Pinus species to EMF using 1,206 contrasts published on 34 species, and matched these data with data on Pinus species invasiveness. Surprisingly, we found that species that are more invasive depend more on mutualisms (EMF). Seedling growth of species with smaller seeds benefited more from mutualisms, indicating a higher dependence. A higher reliance on EMF could be part of a strategy in which small-seeded species produce more seeds that can disperse further, and these species are likely to establish only if facilitated by mycorrhizal fungi. On the contrary, big-seeded species showed a lower dependence on EMF, which may be explained by their tolerance to stressful conditions during establishment. However, the limited dispersal of larger seeds may limit the spread of these species. We present strong evidence against a venerable belief in ecology that species that rely more on mutualisms are less prone to invade, and suggest that in certain circumstances greater reliance on mutualists can increase spread capacity.

Green soybean seeds: effect on physiological quality / Sementes de soja esverdeada: efeito na qualidade fisiológica

The objective of this research was to assess the manner in which the presence of green soybean seeds affects their physiological quality. In this study, six lots of soybean seeds of cultivar 5958RSF IPRO with 0, 0, 7, 8, 16 and 18% of green seeds were examined. The tests done included the first germination count, germination, electrical conductivity, field emergence, accelerated aging, emergence speed index, Tetrazolium, length, dry mass and seedling growth curve. Results were tested employing the normality test and analysis of variance, and the means were compared by the Tukey test at 5% probability level, employing the Rbio statistical program. Growth data were analyzed by the nonlinear regression analytical method, using the SigmaPlot 12.0 software. The viability and vigor of the greenish seeds were confirmed to reveal higher deterioration, proportional to the percentage of seeds in which the cotyledons had green pigmentation, indicating that the presence of chlorophyll caused the physiological quality of the soybean seeds to decrease.(AU)

Neste trabalho o objetivo foi avaliar a influência da presença de sementes esverdeadas de soja na sua qualidade fisiológica. Para tanto, foram utilizados seis lotes de sementes de soja da cultivar 5958RSF IPRO com 0, 0, 7, 8, 16 e 18% de sementes esverdeadas. Os testes realizados foram: primeira contagem de germinação, germinação, condutividade elétrica, emergência em campo, envelhecimento acelerado, índice de velocidade de emergência, tetrazólio, comprimento, massa seca e curva de crescimento de plântulas. Os resultados foram submetidos ao teste de normalidade e análise de variância, seguido de comparações de médias, pelo teste de Tukey ao nível de 5% de probabilidade, com auxílio do programa estatístico Rbio. Os dados de crescimento foram submetidos à análise de regressão não-linear, utilizando o software SigmaPlot 12.0. Para as sementes esverdeadas, constata-se menor viabilidade e vigor devido a maior deterioração, proporcional a porcentagem de sementes com pigmentação verde nos cotilédones, de forma que a presença de clorofila reduz a qualidade fisiológica de sementes de soja.(AU)

Green soybean seeds: effect on physiological quality / Sementes de soja esverdeada: efeito na qualidade fisiológica

ABSTRACT: The objective of this research was to assess the manner in which the presence of green soybean seeds affects their physiological quality. In this study, six lots of soybean seeds of cultivar 5958RSF IPRO with 0, 0, 7, 8, 16 and 18% of green seeds were examined. The tests done included the first germination count, germination, electrical conductivity, field emergence, accelerated aging, emergence speed index, Tetrazolium, length, dry mass and seedling growth curve. Results were tested employing the normality test and analysis of variance, and the means were compared by the Tukey test at 5% probability level, employing the Rbio statistical program. Growth data were analyzed by the nonlinear regression analytical method, using the SigmaPlot 12.0 software. The viability and vigor of the greenish seeds were confirmed to reveal higher deterioration, proportional to the percentage of seeds in which the cotyledons had green pigmentation, indicating that the presence of chlorophyll caused the physiological quality of the soybean seeds to decrease.

RESUMO: Neste trabalho o objetivo foi avaliar a influência da presença de sementes esverdeadas de soja na sua qualidade fisiológica. Para tanto, foram utilizados seis lotes de sementes de soja da cultivar 5958RSF IPRO com 0, 0, 7, 8, 16 e 18% de sementes esverdeadas. Os testes realizados foram: primeira contagem de germinação, germinação, condutividade elétrica, emergência em campo, envelhecimento acelerado, índice de velocidade de emergência, tetrazólio, comprimento, massa seca e curva de crescimento de plântulas. Os resultados foram submetidos ao teste de normalidade e análise de variância, seguido de comparações de médias, pelo teste de Tukey ao nível de 5% de probabilidade, com auxílio do programa estatístico Rbio. Os dados de crescimento foram submetidos à análise de regressão não-linear, utilizando o software SigmaPlot 12.0. Para as sementes esverdeadas, constata-se menor viabilidade e vigor devido a maior deterioração, proporcional a porcentagem de sementes com pigmentação verde nos cotilédones, de forma que a presença de clorofila reduz a qualidade fisiológica de sementes de soja.

Seed local adaptation and seedling plasticity account for Gleditsia triacanthos tree invasion across biomes.

BACKGROUND AND AIMS: Phenotypic plasticity and local adaption can contribute to the success of invasive species. While the former is an environmentally induced trait, the latter involves a selection process to filter the best genotype for a location. We examined the evidence for phenotypic plasticity and local adaptation for seed and seedling traits of the invasive tree Gleditsia triacanthos, with three origins distributed along an approx. 10° latitude gradient across three biomes. METHODS: In sub-tropical forests, dry woodlands and secondary temperate grasslands in Argentina, we harvested seeds from clusters of neighbouring trees (i.e. families) distributed within 15-20 km in each origin (biome). We manipulated the environmental conditions relevant to each biome, assuming that propagule availability did not represent an ecological barrier. In growth chambers, we evaluated seed imbibition and seed germination under different light, temperature and water potential. In a 2 year common garden, we evaluated the impact of resident vegetation removal on seedling survival and growth. KEY RESULTS: Mean time to complete seed imbibition differed among origins; seeds from temperate grasslands reached full imbibition before seeds from dry woodlands and sub-tropical forests. Germination was always >70 %, but was differentially affected by water potential, and light quantity (dark-light) and quality (red-far red) among origins, suggesting local adaptation. In the common garden, vegetation removal rather than origin negatively affected seedling survival and enhanced seedling growth. Vegetation removal increased basal diameter, leaves per plant and spine number, and reduced the height:basal diameter ratio. CONCLUSIONS: We conclude that local adaptation in seed germination traits and plastic changes in seedling allometry (e.g. height:diameter) may allow this tree to respond over the short and long term to changes in environmental conditions, and to contribute to shape G. triacanthos as a successful woody invader. Overall, our study revealed how local adaptation and plasticity can explain different aspects of tree invasion capacity across biomes.

Does oxidative stress determine the thermal limits of the regeneration niche of Vriesea friburgensis and Alcantarea imperialis (Bromeliaceae) seedlings?

The predicted environmental changes may be detrimental to initial seedling growth, particularly the expected increase in air temperature. We therefore investigated the thermal limits for growth and development of Vriesea friburgensis and Alcantarea imperialis seedlings in the context of oxidative stress. The optimal temperatures for the growth of V. friburgensis and A. imperialis were 25 and 25-30 °C, respectively. Extreme temperatures (15, 30, or 35 °C) induced oxidative stress in both species with significant accumulation of hydrogen peroxide (H2O2) and nitric oxide (NO). Under oxidative stress, the amount of chlorophyll decreased in both species, more prominently in V. friburgensis, while carotenoid levels dramatically increased in A. imperialis. Notably, the activities of superoxide dismutase, catalase (CAT), and ascorbate peroxidase increased in A. imperialis at extreme temperatures. Similar results were observed for V. friburgensis; however, the activity of CAT remained unaffected regardless of temperature. Seedlings of A. imperialis survived at a wider range of temperatures than V. friburgensis, which had greater than 40% mortality when growing at 30 °C. Overall, precise control of cellular H2O2 and NO levels takes place during the establishment of A. imperialis seedlings, allowing the species to cope with relatively high temperatures. The thermal limits of the fundamental niches of the species investigated, determined based on the ability of seedlings to cope with oxidative stress, were distinct from the realized niches of these species. The results suggest that recruitment success is dependent on the ability of seedlings to handle extreme temperature-triggered oxidative stress, which limits the regeneration niche.

Toxicity evaluation of process water from hydrothermal carbonization of sugarcane industry by-products.

Hydrothermal carbonization (HTC) is a thermochemical process carried out in an aqueous medium. It is capable of converting biomass into a solid, carbon-rich material (hydrochar), and producing a liquid phase (process water) which contains the unreactive feedstock and/or chemical intermediates from the carbonization reaction. The aim of this study was to evaluate the characteristics of process water generated by HTC from vinasse and sugarcane bagasse produced by sugarcane industry and to evaluate its toxicity to both marine (using Artemia salina as a model organism) and the terrestrial environment (through seed germination studies of maize, lettuce, and tomato). The experiments showed that concentrated process water completely inhibited germination of maize, lettuce, and tomato seeds. On the other hand, diluted process water was able to stimulate seedlings of maize and tomato and enhance root and shoot growth. For Artemia, the LC50 indicated that the process water is practically non-toxic; however, morphological changes, especially damages to the digestive tube and antennas of Artemia, were observed for the concentration of 1000 mg C L-1.

Produção de mudas de Passiflora edulis sob diferentes substratos orgânicos / Production of Passiflora edulis seedlings under different organic substrates

O substrato é um dos fatores de maior importância na produção de mudas de espécies frutíferas, pois garantem as melhores condições de crescimento e estabilidade das mudas no campo. Com isso, objetivou-se avaliar a produção de mudas de maracujazeiro amarelo (Passiflora edulis) com diferentes fontes e proporções de matéria orgânica. O delineamento experimental foi em blocos casualizados, em esquema fatorial 3x4, com 4 repetições, sendo três fontes de matéria orgânica (solo + areia (testemunha); solo + areia + esterco bovino; solo + areia + esterco de galinha e solo + areia + húmus) e quatro proporções (1:1:0, 1:1:1, 1:1:2, 1:1:3), com 10 mudas por tratamento. Foram realizadas avaliações diárias para determinar o índice de velocidade de emergência e a porcentagem de emergência, e aos 60 dias após a semeadura foram avaliados: altura de planta, número de folhas, comprimento radicular, relação H/D, diâmetro do caule, massa fresca e seca das folhas, caule, raiz e total. Com isso, o substrato orgânico contendo húmus e o esterco bovino foram os que propiciaram as melhores condições para produção de mudas de maracujazeiro amarelona proporção 1:1:1 e 1:1:2, respectivamente.(AU)

The substrate is one of the most important factors in the production of seedlings of fruit species, since they guarantee the best conditions of growth and stability of the seedlings in the field. The aim of this study was to evaluate the production of yellow passion fruit seedlings (Passiflora edulis) with different sources and proportions of organic matter. The experimental design was in randomized blocks, in a 3x4 factorial scheme, with 4 replicates, being three sources of organic matter (soil + sand (control), soil + sand + bovine manure, soil + sand + chicken manure and soil + sand + humus) and four ratios (1:1:0, 1:1:1, 1:1:2, 1:1:3), with 10 seedlings per treatment. Daily evaluations were performed to determine the rate of emergence and percentage of germination, and at 60 days after sowing, plant height, leaf number, root length, H/D ratio, stem diameter, fresh mass and dry leaves, stem, root and total. Thus, the organic substrate containing humus and bovine manure provided the best conditions for the production of yellow passion fruit seedlings in a ratio of 1:1:1 to 1:1:2, respectively.(AU)

Produção de mudas de Passiflora edulis sob diferentes substratos orgânicos / Production of Passiflora edulis seedlings under different organic substrates

O substrato é um dos fatores de maior importância na produção de mudas de espécies frutíferas, pois garantem as melhores condições de crescimento e estabilidade das mudas no campo. Com isso, objetivou-se avaliar a produção de mudas de maracujazeiro amarelo (Passiflora edulis) com diferentes fontes e proporções de matéria orgânica. O delineamento experimental foi em blocos casualizados, em esquema fatorial 3x4, com 4 repetições, sendo três fontes de matéria orgânica (solo + areia (testemunha); solo + areia + esterco bovino; solo + areia + esterco de galinha e solo + areia + húmus) e quatro proporções (1:1:0, 1:1:1, 1:1:2, 1:1:3), com 10 mudas por tratamento. Foram realizadas avaliações diárias para determinar o índice de velocidade de emergência e a porcentagem de emergência, e aos 60 dias após a semeadura foram avaliados: altura de planta, número de folhas, comprimento radicular, relação H/D, diâmetro do caule, massa fresca e seca das folhas, caule, raiz e total. Com isso, o substrato orgânico contendo húmus e o esterco bovino foram os que propiciaram as melhores condições para produção de mudas de maracujazeiro amarelona proporção 1:1:1 e 1:1:2, respectivamente.

The substrate is one of the most important factors in the production of seedlings of fruit species, since they guarantee the best conditions of growth and stability of the seedlings in the field. The aim of this study was to evaluate the production of yellow passion fruit seedlings (Passiflora edulis) with different sources and proportions of organic matter. The experimental design was in randomized blocks, in a 3x4 factorial scheme, with 4 replicates, being three sources of organic matter (soil + sand (control), soil + sand + bovine manure, soil + sand + chicken manure and soil + sand + humus) and four ratios (1:1:0, 1:1:1, 1:1:2, 1:1:3), with 10 seedlings per treatment. Daily evaluations were performed to determine the rate of emergence and percentage of germination, and at 60 days after sowing, plant height, leaf number, root length, H/D ratio, stem diameter, fresh mass and dry leaves, stem, root and total. Thus, the organic substrate containing humus and bovine manure provided the best conditions for the production of yellow passion fruit seedlings in a ratio of 1:1:1 to 1:1:2, respectively.

Common bean seed treatment with zinc affects the physiological seed quality and the leaf content of micronutrients / O tratamento de sementes de feijão com zinco afeta a qualidade fisiológica de sementes e o teor foliar de micronutrientes

The study aimed to evaluate the effect of zinc concentration applied to the seed treatment on the physiological quality of bean seeds and leaf content of the micronutrients iron, copper, zinc and manganese of BRS Expedito. The experiment was carried out with common bean seeds obtained from 2014/2015 growing season. The treatments using the following concentrations of zinc were applied via seed treatment with concentrations of 0, 12, 24, 36 and 48 g Zn 100 kg-1 of seed. Emergence assessments of emergence speed index, cold test, length of shoot and roots, dry weight of shoots and roots of seedlings and each micro-nutrient contents: Fe, Cu, Zn and Mn were conducted. The results of the variables emergence, emergence speed index and cold test showed no significant effects of increased Zn concentrations in seed treatment. However, in the analysis of seedling growth, Zn promoted an increase in hair and root length and dry matter produced by both shoot and root. The Zn content in leaf tissue increased manganese according to the increase of the Zn concentration in seed treatment. Seed treatment with Zn promotes increased growth and leaf content of this element to BRS Expedito.(AU)

O trabalho teve com o objetivo avaliar o efeito de concentrações de zinco aplicado ao tratamento de sementes sobre a qualidade fisiológica de sementes de feijão e o teor foliar dos micronutrientes ferro (Fe), cobre (Cu), zinco (Zn) e manganês (Mn) para a cultivar BRS Expedito. O trabalho foi desenvolvido com sementes obtidas na safra agrícola 2014/2015. Os tratamentos foram constituídos pelas seguintes concentrações de Zn aplicados via tratamento de sementes com concentrações de 0, 12, 24, 36 e 48 g Zn 100 kg-1 de sementes. Foram realizadas as avaliações de emergência, índice de velocidade de emergência, teste de frio, comprimento de parte aérea e radicular, massa seca de parte aérea e radicular de plântulas e determinação dos teores de micronutrientes (Fe, Cu, Zn e Mn). Os resultados das variáveis emergência, índice de velocidade de emergência e teste de frio não apresentaram efeitos significativos decorrentes do aumento das concentrações de Zn no tratamento de sementes. Entretanto, na análise do crescimento das plântulas, o Zn promoveu aumento no comprimento radicular e aéreo e na massa seca produzida, tanto parte aérea como de raiz. O teor de Zn no tecido foliar aumentou e o de manganês reduziu de acordo com o aumento da concentração de zinco no tratamento de sementes. O tratamento de sementes com Zn promove aumento no crescimento e no teor foliar deste elemento para a cultivar BRS Expedito.(AU)

Common bean seed treatment with zinc affects the physiological seed quality and the leaf content of micronutrients / O tratamento de sementes de feijão com zinco afeta a qualidade fisiológica de sementes e o teor foliar de micronutrientes

The study aimed to evaluate the effect of zinc concentration applied to the seed treatment on the physiological quality of bean seeds and leaf content of the micronutrients iron, copper, zinc and manganese of BRS Expedito. The experiment was carried out with common bean seeds obtained from 2014/2015 growing season. The treatments using the following concentrations of zinc were applied via seed treatment with concentrations of 0, 12, 24, 36 and 48 g Zn 100 kg-1 of seed. Emergence assessments of emergence speed index, cold test, length of shoot and roots, dry weight of shoots and roots of seedlings and each micro-nutrient contents: Fe, Cu, Zn and Mn were conducted. The results of the variables emergence, emergence speed index and cold test showed no significant effects of increased Zn concentrations in seed treatment. However, in the analysis of seedling growth, Zn promoted an increase in hair and root length and dry matter produced by both shoot and root. The Zn content in leaf tissue increased manganese according to the increase of the Zn concentration in seed treatment. Seed treatment with Zn promotes increased growth and leaf content of this element to BRS Expedito.

O trabalho teve com o objetivo avaliar o efeito de concentrações de zinco aplicado ao tratamento de sementes sobre a qualidade fisiológica de sementes de feijão e o teor foliar dos micronutrientes ferro (Fe), cobre (Cu), zinco (Zn) e manganês (Mn) para a cultivar BRS Expedito. O trabalho foi desenvolvido com sementes obtidas na safra agrícola 2014/2015. Os tratamentos foram constituídos pelas seguintes concentrações de Zn aplicados via tratamento de sementes com concentrações de 0, 12, 24, 36 e 48 g Zn 100 kg-1 de sementes. Foram realizadas as avaliações de emergência, índice de velocidade de emergência, teste de frio, comprimento de parte aérea e radicular, massa seca de parte aérea e radicular de plântulas e determinação dos teores de micronutrientes (Fe, Cu, Zn e Mn). Os resultados das variáveis emergência, índice de velocidade de emergência e teste de frio não apresentaram efeitos significativos decorrentes do aumento das concentrações de Zn no tratamento de sementes. Entretanto, na análise do crescimento das plântulas, o Zn promoveu aumento no comprimento radicular e aéreo e na massa seca produzida, tanto parte aérea como de raiz. O teor de Zn no tecido foliar aumentou e o de manganês reduziu de acordo com o aumento da concentração de zinco no tratamento de sementes. O tratamento de sementes com Zn promove aumento no crescimento e no teor foliar deste elemento para a cultivar BRS Expedito.

Seedling growth and survival of five tree species in secondary forests and adjacent pastures in the montane rain forests of Southern Costa Rica / Crecimiento y supervivencia de plántulas de cinco especies de árboles en bosques secundarios y pastizales adyacentes en un bosque lluvioso montano del sur de Costa Rica

Abstract:Successful forest restoration in tropical environments is limited by the paucity of studies on the initial establishment and early survival requirements of seedlings of most native tropical tree species under disturbed conditions. Here, we evaluated the initial growth responses and the regeneration potential of seedlings of five tree species native to Costa Rica (Hasseltia floribunda, Inga densiflora, Persea americana, Tapirira mexicana and Trichilia pittieri). Seedlings were grown in secondary forests and adjacent open pastures under contrasting conditions of light availability. We quantified seedling growth, survival and herbivory from August 2010 to August 2011 on a monthly basis, and measured differences in leaf mass per area (LMA) at the end of the experiment. We found significant variation in growth responses between the understory of secondary forests and pastures. Growth in height was highest in pastures across all species, with I. densiflora, P. americana and T. mexicana showing the most striking differences. In contrast, H. floribunda and T. pittieri did not show differences in diameter growth between environments. Except for T. mexicana, herbivory increased throughout the experiment in all the species. Herbivory increased faster in pastures for H. floribunda and T. pittieri and showed higher rates in the forest understory for I. densiflora and P. americana. Seedling survival showed significant differences for all species across environments. Survival of H. floribunda and I. densiflora was higher in secondary forests, whereas the other species showed higher survival in pastures. LMA showed higher values in the pastures across all species, showing that individuals exposed to high light conditions had great photosynthetic rate and great leaf construction capacity. Due to their rapid growth and high survival, I. densiflora and T. mexicana showed great potential to restore abandoned pastures and secondary forests. Increasing our knowledge on the response of seedlings under disturbed conditions in tropical ecosystems is critical for improving the restoration of altered environments by matching the ecological amplitude of native species with specific environmental conditions. Rev. Biol. Trop. 64 (4): 1565-1583. Epub 2016 December 01.

Resumen:La restauración exitosa del bosque en ambientes tropicales está limitada por la carencia de estudios sobre los requisitos de hábitat, el establecimiento inicial, y la sobrevivencia de las plántulas de la mayoría de las especies de árboles tropicales nativos. En este estudio, evaluamos las respuestas en el crecimiento inicial y el potencial de regeneración de las plántulas de cinco especies de árboles nativos de Costa Rica (Hasseltia floribunda, Inga densiflora, Persea americana, Tapirira mexicana y Trichilia pittieri). Sembramos las plántulas en bosques secundarios y en pastizales abiertos adyacentes con condiciones de luz contrastantes. Cuantificamos el crecimiento, la supervivencia y el daño por herbivoría de las plántulas de forma mensual entre agosto 2010 y agosto 2011, y medimos las diferencias en el la masa foliar por área de la hoja al final del experimento. Existió una variación significativa en el crecimiento de las plántulas expuestas a la sombra en los bosques secundarios y aquellas que crecieron en pastizales. El crecimiento en altura fue mayor en pastizales en todas las especies; I. densiflora, P. americana y T. mexicana mostraron la mayor diferencia entre ambientes. En con- traste, H. floribunda y T. pittieri no mostraron diferencias en el crecimiento del diámetro entre ambientes. Con la excepción de T. mexicana, todas las especies mostraron un aumento en herbivoría durante el estudio. En los pastizales, el incremento de la herbivoría fue más rápido en H. floribunda y T. pittieri, mientras que para I. densiflora y P. americana fue mayor en el bosque. La sobrevivencia de plántulas fue diferente entre ambientes para todas las especies. La sobrevivencia de H. floribunda e I. densiflora fue mayor en el bosque secundario, mientras que en las demás especies hubo mayor sobrevivencia de plántulas en los pastizales. La masa foliar por área fue mayor en las plántulas que crecieron en los pastizales que en bosque secundario para todas las especies, lo que sugiere que los individuos que crecieron en condiciones de alta incidencia de luz tuvieron mayor tasa fotosintética y mayor capacidad de construcción de la hoja. Debido al rápido crecimiento y alta supervivencia I. densiflora y T. mexicana tienen gran potencial para la restauración de bosques secundarios y pastizales abandonados. Generar información sobre la respuesta de plántulas creciendo en bosques secundarios y pastizales en regeneración es crítico para mejorar los procesos de restauración de ambientes alterados. La restauración de estos bosques depende de la correspondencia entre las condiciones específicas de hábitat y la plasticidad ecológica de las especies nativas.

On the role of a Lipid-Transfer Protein. Arabidopsis ltp3 mutant is compromised in germination and seedling growth.

Plant Lipid-Transfer Proteins (LTPs) exhibit the ability to reversibly bind/transport lipids in vitro. LTPs have been involved in diverse physiological processes but conclusive evidence on their role has only been presented for a few members, none of them related to seed physiology. Arabidopsis seeds rely on storage oil breakdown to supply carbon skeletons and energy for seedling growth. Here, Arabidopsis ltp3 mutant was analyzed for its ability to germinate and for seedling establishment. Ltp3 showed delayed germination and reduced germination frequency. Seedling growth appeared reduced in the mutant but this growth restriction was rescued by the addition of an exogenous carbon supply, suggesting a defective oil mobilization. Lipid breakdown analysis during seedling growth revealed a differential profile in the mutant compared to the wild type. The involvement of LTP3 in germination and seedling growth and its relationship with the lipid transfer ability of this protein is discussed.