Myracrodruon urundeuva, a native species from the Brazilian Caatinga, is widely distributed across its endemic region, where it also plays an essential socioeconomic role. The objective of this study was to evaluate the influence of environmental stress on the germination of M. urundeuva seeds harvested in different years (2010 to 2013). Seeds were germinated at constant temperatures between 10 to 40 °C, osmotic potentials from 0 to -0.8 MPa (in polyethylene glycol 6000 solutions), and from 0 to -0.5 MPa (in NaCl solutions). The experiment was conducted according to a completely randomized design, with three replicates of 50 seeds, in a factorial scheme (harvest year x stress intensity) for each environmental stress. Germination data were then analysed using thermal, hydro and halo time models, and future germination responses projected according to climate change scenarios. The germination thermal thresholds ranged from 7.4 to 53.3 oC. The germination base osmotic threshold (using polyethylene glycol) was -0.6 MPa and the base osmotic threshold in NaCl was -0.43MPa. Seeds from different harvest years showed distinct tolerance to environmental stresses. The thermal, hydro and halo-time models were efficient to describe the germinative response of seeds, and the climate models allowed to identify the germination responses of M. urundeuva in future climate. According to the models for future climate (RCP 8.5), the reduction of rainfall by 2100 will directly affect seed germination and seedling recruitment of M. urundeuva.
-Angico is a species found in several environments in Brazil, with several applications. It is used in the timber industry and mainly in folk medicine. In order to verify a variation in the biometric characteristics and the quality of seeds from different mother-plants in different harvesting years, the following variables were studied: moisture content, diameter, density, electrical conductivity, fresh and dry matter of seedlings, germination percentage and kinetics, in a completely randomized design with a 2x3 factorial arrangement (lots x size). The obtained results showed that angico seeds from different lots showed different physiological quality, possibly due to the climate variations to which mother-plants were submitted in the different years. Seed size directly interferes with seedling growth under both controlled and greenhouse conditions, and it can be used as a vigor indicator for angico seeds.Index terms: physiological quality, biometrics, Fabaceae, angico.Tamanho e vigor de sementes de Anadenanthera colubrina (Vell.)Brenan colhidas em área de Caatinga RESUMO -O angico é uma espécie encontrada em diversos ambientes no Brasil, e apresenta diversas aplicações, sendo utilizado pela indústria madeireira e principalmente na medicina popular. Buscando-se verificar a variação quanto a caracteres biométricos e qualidade de sementes provenientes de diferentes matrizes em diferentes anos de coleta, desenvolveram-se ensaios após o beneficiamento das sementes, em que foram avaliados: teor de água, diâmetro, densidade, condutividade elétrica, matéria fresca e seca de plântulas, porcentagem e cinética de germinação, em delineamento inteiramente casualizado com esquema fatorial 2x3 (lotes x tamanho). Os resultados obtidos demostraram que sementes de angico de diferentes lotes apresentam qualidade fisiológica distinta, possivelmente pelas variações do clima as quais as árvores matrizes foram submetidas nos diferentes anos de coleta. O tamanho das sementes interfere diretamente no crescimento de plântulas tanto em condições controladas, quanto em casa de vegetação, podendo ser utilizado como indicativo de vigor para sementes de angico.Termos para indexação: qualidade fisiológica, biometria, Fabaceae, angico.
Seasonally tropical dry forests are among the most threatened environments by climate change. However, these forests, which are at risk of desertification, are still poorly studied and conserved. Seeds of several species endemic to the Caatinga, a Brazilian dry forest, are also understudied, mainly regarding their ability to cope with a hotter and drier climate predicted for the future. For the first time in seeds of Cenostigma microphyllum (Leguminosae), we aimed to study the presence of physical dormancy, temperature and salt tolerance to ascertain the effects of current and future climate on seed germination. Intact and scarified seeds were investigated by incubating at constant temperatures (15 to 40°C) or in NaCl solutions (−0.2 to −1.0 MPa) at 25 and 30°C. Thermal and osmotic thresholds, as well as thermal time and hydrotime constants, were calculated using linear regressions between the germination conditions and germination rate. To predict germination in the future, a heat sum model based on thermal time and hydrotime was applied to current and future climate scenarios. Seeds of C. microphyllum were permeable to water and did not have physical dormancy. The results indicated that increases in temperature are unlikely to affect germination, despite greater sensitivity to salinity presented at higher temperatures. In a future climate, the reduction in the number of weeks with at least 15 mm rainfall will affect the germination timing for the seeds. Thus, we can conclude that under the most pessimistic climate scenario predicted for the future, the seed germination of C. microphyllum may be restricted, likely leading to low seedling recruitment and establishment.Keywords temperature . salt stress . climate change . thermal time model . hydrotime model
The Caatinga dry forest species are well adapted and resilient to the climatic conditions of the Brazilian semiarid region. However, this is one of the more vulnerable ecosystems to climate change, due to increasing deforestation and drought in the last years. Water shortage in this region has prompted studies into the possibility of safe brackish water use/reuse for forage and forest seedling production. We tested, in this study, alternative sources to potable water to irrigate forest seedlings in nurseries, which have high water expenditure. The trail was performed in a completely randomized design with three irrigation water sources and four replications with five seedlings. Biosaline fish cropping water; brackish groundwater and tap water were used for irrigation of seedlings of Anadenanthera colubrina, Erythrina velutina and Aspidosperma pyrifolium, grown in a screened nursery greenhouse in polyethylene bags filled with sand and soil (1:1 v/v). Seed germination and seedlings growth were evaluated for up to 80 days. Results showed that irrigation with biosaline fish farming waste water with electrical conductivity values > 6 dS.m -1 did not compromise the seed germination nor the seedlings growth in nursery. Brackish ground water, however, slowed the development of seedlings. Faced with the possibility of water shortages due to climate change, the use of non-potable sources of water, can therefore, be an alternative and low input technique for the production of seedlings of native species from Caatinga. ResumoAs espécies florestais da Caatinga estão adaptadas e são resilientes às condições climáticas da região semiárida brasileira. No entanto, este é um dos ecossistemas mais vulneráveis às mudanças climáticas, devido ao aumento do desmatamento e à seca dos últimos anos. A escassez de água nessa região induziu estudos sobre a possibilidade de utilização/reutilização segura da água salobra para a produção de forragem e de mudas florestais. Testaram-se, nesse estudo, fontes alternativas à água potável para irrigação de mudas florestais em viveiros, que apresentam elevado gasto de água. O ensaio foi realizado em delineamento inteiramente casualizado com três fontes de água para irrigação e quatro repetições de cinco plântulas. Água biossalina, provinda de cultivo de peixe; água subterrânea salobra e água de abastecimento foram utilizadas para irrigar mudas de Anadenanthera colubrina, Erythrina velutina e Aspidosperma pyrifolium, cultivadas em viveiro telado em embalagens de polietileno preenchidas com areia e solo (1:1, v/v). A porcentagem de germinação das sementes e o crescimento das mudas foram avaliados até 80 dias. Os resultados mostraram que a irrigação com água biossalina residual de piscicultura, com valores de condutividade elétrica < 6 dS.m -1 não comprometeu a germinação das sementes, nem o crescimento de mudas em viveiro. A água salobra subterrânea reduziu a velocidade de desenvolvimento das mudas. Diante a possibilidade de escassez de água devido às mudanças do clima, o uso de fontes não potáveis de ...
As mudanças climáticas, especialmente o aumento da temperatura e da concentração de gases de efeito estufa na atmosfera , afetarão o crescimento e desenvolvimento das plantas. O objetivo deste trabalho foi avaliar o efeito de aumento da temperatura e da concentração de CO2 na emergência de plântulas de cebola das cultivares Alfa São Francisco, Franciscana IPA 10, Vale Ouro IPA 11 e Serena .O experimento foi conduzido em câmaras de crescimento, com controle de umidade, luminosidade, temperatura e CO2, durante 12 dias. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 4x4x2, com quatro cultivares de cebola, quatro temperaturas (25 ºC; 28 ºC; 31 ºC e 34 ºC) e duas concentrações de CO2 (380 e 770 ppm) e , com quatro repetições e 36 sementes por tratamento. Sementes de cebola das cultivares Alfa São Francisco, Franciscana IPA 10, Vale Ouro IPA 11 e Serena foram semeadas em bandejas de polietileno com 36 células contendo substrato comercial e mantido nas diferentes concentrações de CO2 e temperatura. Foram avaliados a porcentagem de emergência, tempo médio de emergência, velocidade de emergência, índice de velocidade de emergência, comprimento da parte aérea e comprimento da raiz principal. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Scott Knott a 5% de probabilidade. As concentrações de CO2 e as diferentes temperaturas proporcionaram efeitos significativos entre as cultivares para a maioria das variáveis analisadas. O aumento de CO2 e temperatura influenciaram no processo de emergência de plântulas de cebola. Climate change, especially atmosphere temperature and concentration of greenhouse gases increase, will affect plant growth and development . The aim of this study was to evaluate the effect of increased temperature and CO2 concentration in emergence of seedlings of onion cultivars Alfa San Francisco, Franciscan IPA 10, Valley IPA 11 Gold and Serena. The experiment was conducted in growth chambers with humidity, light, temperature and CO2 control during 12 days. The experimental design was completely randomized in a 4x4x2 factorial scheme, with four onion cultivars , four temperatures (25 °C; 28 °C, 31 °C and 34 °C and two concentrations of CO2 (380 to 770 ppm), with four replications and 36 seeds per treatment. Seeds of onion cultivars Alfa São Francisco, Franciscana IPA 10, Vale Ouro IPA 11 and Serena were sown in plastic trays with 36 cells containing commercial substrate and placed in different CO2 concentrations and temperature. Emergence percentage, average time of emergence, emergence speed, emergence speed index, shoot length and root length was evaluated. The data were submitted to variance analysis and the averages compared by Scott Knott test at 5% probability. The CO2 concentrations and different temperatures produced different effects among cultivars for most of the variables. The increase of CO2 and temperature influence the emergence onion seedlings process. Key-words: climate change, impacts, agriculture
-Zephyranthes sylvatica is a beautiful lily, endemic from the Brazilian Caatinga. Although it has a great ornamental potential, little is known about this species, especially regarding its seeds germination process. Aiming to characterize the germination of Z. sylvatica seeds, we studied its imbibition curve, optimum temperature and substrate for germination and seedling emergence, osmotic and salt stress tolerance, as well as the tolerance to frosting/ defrosting, which indicates long term cryostorage potential. The germination of Z. sylvatica presents a triphasic model of imbibition, in which the primary root protrusion occurs after 72 hours of imbibition. The ideal conditions for evaluating seed germination of Z. sylvatica is 25 °C, in paper rolls. These seeds are highly tolerant to osmotic stress, but not to salt stress. Z. sylvatica seeds can be cryopreservated without loss of germination and seed vigor.Index terms: caatinga, lily, vigor, propagation.Caracterização da germinação de lírio-da-caatinga (Zephyranthes sylvatica (Mart.) Baker (Amarilidacea)RESUMO -Zephyranthes sylvatica é um lindo lírio, endêmico da Caatinga brasileira. Embora tenha um grande potencial ornamental, pouco se sabe sobre esta espécie, especialmente em relação ao processo germinativo de suas sementes. Visando caracterizar a germinação de sementes de Z. sylvatica, estudou-se a sua curva de embebição, temperatura e substrato ótimos para a germinação e emergência das plântulas, tolerância aos estresses osmótico e salino, assim como a tolerância ao congelamento / descongelamento que indica o potencial crioarmazenamento a longo prazo. Baseado nos dados obtidos pode-se concluir que a germinação de Z. sylvatica apresenta modelo trifásico de embebição, em que a protrusão da raiz ocorre após 72 horas de embebição. As condições ideais para a avaliação da germinação das sementes de Z. sylvatica é de 25 °C, em rolos de papel. Estas sementes são altamente tolerantes ao estresse osmótico, mas não ao estresse salino. Sementes de Z. sylvatica podem ser criopreservadas sem perda de germinação e vigor das sementes.Termos para indexação: caatinga, lírio, vigor, propagação.1
Artigo recebido em 10/09/2015 e aceito em 30/11/2015. RESUMOAs mudanças climáticas, especialmente o aumento da temperatura e da concentração de gases de efeito estufa na atmosfera , afetarão o crescimento e desenvolvimento das plantas. O objetivo deste trabalho foi avaliar o efeito de aumento da temperatura e da concentração de CO2 na emergência de plântulas de cebola das cultivares Alfa São Francisco, Franciscana IPA 10, Vale Ouro IPA 11 e Serena. O experimento foi conduzido em câmaras de crescimento, com controle de umidade, luminosidade, temperatura e CO2, durante 12 dias. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 4x4x2, com quatro cultivares de cebola, quatro temperaturas (25 ºC; 28 ºC; 31 ºC e 34 ºC) e duas concentrações de CO2 (380 e 770 ppm) e , com quatro repetições e 36 sementes por tratamento. Sementes de cebola das cultivares Alfa São Francisco, Franciscana IPA 10, Vale Ouro IPA 11 e Serena foram semeadas em bandejas de polietileno com 36 células contendo substrato comercial e mantido nas diferentes concentrações de CO2 e temperatura. Foram avaliados a porcentagem de emergência, tempo médio de emergência, velocidade de emergência, índice de velocidade de emergência, comprimento da parte aérea e comprimento da raiz principal. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Scott Knott a 5% de probabilidade. As concentrações de CO2 e as diferentes temperaturas proporcionaram efeitos significativos entre as cultivares para a maioria das variáveis analisadas. O aumento de CO2 e temperatura influenciaram no processo de emergência de plântulas de cebola. Palavras-chave: mudanças climáticas, impactos, agricultura ABSTRACT Climate change, especially atmosphere temperature and concentration of greenhouse gases increase, will affect plant growth and development . The aim of this study was to evaluate the effect of increased temperature and CO2 concentration in emergence of seedlings of onion cultivars Alfa San Francisco, Franciscan IPA 10, Valley IPA 11 Gold and Serena. The experiment was conducted in growth chambers with humidity, light, temperature and CO2 control during 12 days. The experimental design was completely randomized in a 4x4x2 factorial scheme, with four onion cultivars , four temperatures (25 °C; 28 °C, 31 °C and 34 °C and two concentrations of CO2 (380 to 770 ppm), with four replications and 36 seeds per treatment. Seeds of onion cultivars Alfa São Francisco, Franciscana IPA 10, Vale Ouro IPA 11 and Serena were sown in plastic trays with 36 cells containing commercial substrate and placed in different CO2 concentrations and temperature. Emergence percentage, average time of emergence, emergence speed, emergence speed index, shoot length and root length was evaluated. The data were submitted to variance analysis and the averages compared by Scott Knott test at 5% probability. The CO2 concentrations and different temperatures produced different effects among cultivars for most of the variables. The increase of CO...
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