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Introduction: Spondias tuberosa is a tree endemic to the semiarid region of Brazil with fruticulture potential. Objective: To estimate the diversity and genetic structure of S. tuberosa accessions from four areas of the semiarid region of Brazil, in order to facilitate conservation genetic resources studies in this species. Methods: DNA was extracted, using the CTAB 2x method, from leaf samples of 24 accessions of S. tuberosa available in the germplasm bank at Embrapa Semiárido, Brazil. Ten microsatellite loci were used in this study. Results: The UPGMA dendrogram, generated with a Jaccard coefficient similarity matrix, contains four groups at a 0.44 cutoff point. The similarity coefficient ranged from 0.30 to 0.84, indicating great divergence among the accessions. A Bayesian analysis conducted with the software Structure suggests there are two subpopulations, one formed by accessions from the Januária region and another by accessions from the Juazeiro, Uauá and Petrolina regions. The ΦST value of 0.12 for the analysis of molecular variance indicates moderate genetic differentiation among the four populations, suggesting that the genetic variability is moderately structured in function of region. Conclusions: Together, the analyses indicate that the genetic diversity of S. tuberosa is not uniformly distributed in the studied regions. Thus, germplasm from a greater number of populations should be collected to increase the germplasm bank genetic diversity of the species. Resumen Introducción: Spondias tuberosa es un árbol endémico de la región semiárida de Brasil con potencial frutícola. Objetivo: Estimar la diversidad y caracterizar la estructura genética de accesiones de S. tuberosa en cuatro áreas del semiárido brasileño, para así facilitar estudios de conservación de recursos genéticos de esta especie. Metodología: El ADN fue extraído utilizando el método CTAB 2x a partir de muestras de hojas de 24 accesiones de S. tuberosa disponibles en el banco de germoplasma de Embrapa Semiárido, Brasil. Diez loci de microsatélites fueron usados en este estudio. Resultados: El dendrograma UPGMA generado con una matriz de similitud de coeficientes de Jaccard, formó cuatro grupos con punto de corte en 0.44. El coeficiente de similitud osciló entre 0.30 y 0.84, indicando una gran divergencia entre las accesiones. El análisis Bayesiano realizado en el software Structure sugiere la existencia de dos subpoblaciones, una formada por las accesiones de la región de Januária y otra derivada de las regiones de Juazeiro, Uauá y Petrolina. El valor de ΦST de 0.12 derivado del análisis molecular de la varianza indica moderada variación genética entre las cuatro poblaciones, sugiriendo que la variabilidad genética se estructura moderadamente en función de la región. Conclusiones: Los análisis en conjunto indican que la diversidad genética de S. tuberosa no se encuentra distribuida uniformemente en las regiones estudiadas. Por lo tanto, se debe recolectar germoplasma de un mayor número de poblaciones para aumentar la diversidad genética del banco actual de la especie.

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. Resumo: Myracrodruon urundeuva, espécie nativa da Caatinga e de ampla distribuição geográfica, apresenta relevante valor socioeconômico. Objetivou-se avaliar a influência de estresses ambientais sobre a germinação de lotes de diferentes safras de M. urundeuva. Foram testadas as temperaturas constantes de 10 a 40 °C e potenciais osmóticos de 0 a -0,8 MPa (usando-se polietileno glicol 6000) e de 0 a -0,5 MPa (usando-se soluções de NaCl). O delineamento experimental foi inteiramente casualizado com três repetições de 50 sementes em esquema fatorial (safras x intensidade do estresse) para cada estresse abiótico. Os dados de germinação foram então analisados utilizando modelos de tempo térmico, hídrico, hálico (salino), projetando respostas de germinação em cenários climáticos futuros. Os limites térmicos para a germinação das sementes variaram entre 7,4 e 53,3 oC. O limite osmótico base para germinação de sementes em polietileno glicol foi de -0,6 MPa e em NaCl foi de -0,43 MPa. Segundo modelos de cenários futuros de mudanças climáticas, a redução de semanas com precipitação mínima afetará diretamente a germinação de sementes e o recrutamento de plântulas de M. urundeuva. Assim, conclui-se que sementes de M. urundeuva foram tolerantes aos estresses abióticos. Os modelos de tempo térmico, hídrico e hálico foram eficientes para descrever a resposta foram eficientes para descrever a resposta germinativa de sementes, e os modelos climáticos permitiram identificar as respostas germinativas de M. urundeuva em cenários futuros de mudanças climáticas. De acordo com os modelos para clima futuro (RCP 8.5), a redução da precipitação até 2100 afetará diretamente a germinação de sementes e recrutamento de plântulas de M. urundeuva.

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. Made available in DSpace on 2020-01-20T18:08:04Z (GMT). No. of bitstreams: 1 BiosalineproductionofseedlingsofnativespeciesfromtheCaatinga2019.pdf: 1918882 bytes, checksum: 553eecd301621b68f832e921236492e4 (MD5) Previous issue date: 2019

Poincianella pyramidalis (Fabaceae), Schinopsis brasiliensis (Anacardiaceae) and Sideroxylon obtusifolium (Sapotaceae) are native species of the Caatinga vegetation from northeastern Brazil and have both biological importance and potential economic uses. Little is known about the water uptake and degradation of storage proteins during seed germination of these species. The aim of this study was to evaluate the imbibition and quantify the amount of storage proteins during seed germination of P. pyramidalis, S. brasiliensis and S. obtusifolium. Two lots of S. obtusifolium seeds with different vigour were used. Four replicates of 20 seeds of P. pyramidalis, S. brasiliensis and S. obtusifolium, were sown onto gerboxes with blotting paper soaked in distilled water and incubated during 72, 200 and 624 hours. Before and after imbibition seeds were weighed and frozen at until the sequential extraction and analysis of the seed storage proteins. Based on our results, we conclude that seed germination of P. pyramidalis, S. brasiliensis and S. obtusifolium has a well-defined triphasic imbibition. All storage proteins content of P. pyramidalis and S. brasiliensis seeds degraded along with the seed imbibition. Likewise, the content of albumins, globulins and glutelins decreased as S. obtusifolium seeds absorbed water.

In semi-arid environments, the distribution of rainfall over time is decisive in emergence in a soil seed bank. The objective of this work was to evaluate the effect of rainfall events on the soil seed bank emergence of Caatinga species under high CO 2 concentration. The experiment was carried out in an experimental area of Embrapa Semi-arid in a randomized complete block design, with subdivided plots. Each plot consisted of different environmental conditions (open top greenhouse with injection of 550 ppm CO 2 ; open top greenhouse and environmental CO 2 ; natural environment). The subplots consisted of the depth at which the seeds of Poincianella pyramidalis and Myracrodruon urundeuva were sown (superficially and buried at 0.02 m and 0.06 m depth). Seedling emergence was monitored daily after the first rains. During the experiment, weather data showed a rainfall volume of 83 mm, an average air temperature of 28.7 o C, average soil temperature of 35.4 e 34.9 o C, at depths of 0.02 and 0.06 m, respectively. Seedling emergence started 56 days after sowing and 4 days after the first rains. After 154 days of the start of the experiment, drip irrigation was performed. The greenhouse environment, regardless of the addition of CO 2 or not, allowed higher emergence percentage of P. pyramidalis . The seeds of this species sowed on the soil surface only emerged when irrigation started. M. urundeuva seeds showed low germination even after irrigation.

The seed physiological quality is related with climate variation during development. Thus, the aim of this study was to determinate the relation among climatic factors and germination of M. urundeuva seeds in different growing seasons and to predict the germination according to the climatic scenarios. Seeds from 14 crop seasons (2005 to 2018) and climatic data from the ‘Bebedouro’ weather station (Embrapa Semiarid) were used to determine the influence of climatic conditions on the vegetative, female and male flowers and the fruiting of M. urundeuva . The simple linear correlation and the multiple linear regression model were applied to determine the influence of climatic elements on the production of M. urundeuva seeds. The multivariate calibration model was developed using the previous selection of variables by the algorithm of successive projections. From the mathematical model, the germination of M. urundeuva seeds was predicted according to climate change, as provided by the IPCC. Seed germination showed a significant difference between harvests. Through the correlation it was observed that the temperature correlated negatively with all phenological phases of M. urundeuva . The quality of M. urundeuva seeds is related to the maximum, average and minimum temperature, average and minimum humidity, and precipitation. These climate variables during the different phenological phases of M. urundeuva affect the physiological quality of the seeds, and, in climate change scenarios, there will be a reduction in the seed production of this species. O clima e a producao de sementes de Myracrodruon urundeuva Allemao RESUMO A qualidade fisiologica das sementes esta relacionada as variacoes climaticas durante o seu desenvolvimento. Assim, o objetivo deste trabalho foi determinar a relacao entre os elementos climaticos e a germinacao de diferentes safras de sementes de M. urundeuva , bem como prever a germinacao frente aos cenarios climaticos. Foram utilizadas sementes de 14 safras (2005 a 2018) e os dados climaticos da estacao meteorologica de Bebedouro, pertencente a Embrapa Semiarido, para determinar a influencia das condicoes climaticas nas fases vegetativa, flores femininas e masculinas e da frutificacao de M. urundeuva . A correlacao linear simples e o modelo de regressao linear multipla foram aplicados para determinar a influencia dos elementos climaticos na producao de sementes de M. urundeuva . O modelo de calibracao multivariado foi desenvolvido empregando a selecao previa de variaveis pelo algoritmo das projecoes sucessivas. A partir do modelo matematico realizou-se a previsao da germinacao de sementes de M. urundeuva frente as mudancas climaticas, previstas pelo IPCC. A germinacao das sementes apresentou diferenca significativa entre as safras. Por meio da correlacao observou-se que a temperatura correlacionou negativamente com todas as fases fenologicas da M. urundeuva . A qualidade das sementes de M. urundeuva esta relacionada com a temperatura maxima, media e minima, umidade media e minima, e com a precipitacao. Essas variaveis de clima durante as diferentes fases fenologicas de M. urundeuva afetam a qualidade fisiologica das sementes, sendo que, em cenarios de mudancas climaticas, ocorrera uma reducao na producao de sementes desta especie. Palavras-chave: aroeira-do-sertao, mudancas climaticas, germinacao.

Drylands are predicted to become more arid and saline due to increasing global temperature and drought. Although species from the Caatinga, a Brazilian tropical dry forest, are tolerant to these conditions, the capacity for germination to withstand extreme soil temperature and water deficit associated with climate change remains to be quantified. We aimed to evaluate how germination will be affected under future climate change scenarios of limited water and increased temperature. Seeds of three species were germinated at different temperatures and osmotic potentials. Thermal time and hydrotime model parameters were established and thresholds for germination calculated. Germination performance in 2055 was predicted, by combining temperature and osmotic/salt stress thresholds, considering soil temperature and moisture following rainfall events. The most pessimistic climate scenario predicts an increase of 3.9 °C in soil temperature and 30% decrease in rainfall. Under this scenario, soil temperature is never lower than the minimum and seldomly higher than maximum temperature thresholds for germination. As long as the soil moisture (0.139 cm3 cm3) requirements are met, germination can be achieved in 1 day. According to the base water potential and soil characteristics, the minimum weekly rainfall for germination is estimated to be 17.5 mm. Currently, the required minimum rainfall occurs in 14 weeks of the year but will be reduced to 4 weeks by 2055. This may not be sufficient for seedling recruitment of some species in the natural environment. Thus, in future climate scenarios, rainfall rather than temperature will be extremely limiting for seed germination. Made available in DSpace on 2020-02-21T18:10:31Z (GMT). No. of bitstreams: 1 Rainfallnotsoiltemperaturewilllimittheseedgerminationofdry2020.pdf: 3202683 bytes, checksum: 1a6594dd57f074a3945a09b035657ac6 (MD5) Previous issue date: 2020

As condições de armazenamento são determinantes para garantia da qualidade fisiológica das sementes e, embora a sua qualidade não possa ser melhorada, boas condições durante este período contribuirão para mantê-las viáveis por um tempo mais longo, retardando o processo de deterioração. A manutenção da viabilidade das sementes de frutos carnosos através do armazenamento vem sendo uma das linhas de pesquisa mais importantes para as sementes de grande número de espécies. Diante do exposto, objetivou-se com o presente trabalho avaliar a influência dos diferentes tipos de embalagens, ambientes, e do período de armazenamento sobre a germinação e vigor das sementes de abóbora ‘Jacarezinho’. O trabalho foi conduzido no Laboratório de Análise de Sementes da Embrapa Semiárido, em Petrolina – PE. As sementes foram acondicionadas em embalagens de papel e de plástico (tereftalato de polietileno) e mantidas em ambiente de laboratório e em câmara fria com 10 oC e 45% de UR. As sementes foram avaliadas antes e durante o armazenamento por três, seis e doze meses. Foram avaliados o teor de água, a germinação e o vigor das sementes. Dentre os principais resultados, pode-se constatar que é viável armazenar sementes de abóbora ‘Jacarezinho’ com 6% de teor de água durante doze meses, pois a dormência endógena é superada após este período de conservação. A embalagem de plástico foi considerada a mais adequada assim como o ambiente de laboratório com 29 oC e 45% de UR para as condições climáticas de Petrolina - PE. Os maiores valores de germinação foram obtidos em embalagem de plástico (95%) para os doze meses e papel com 91%, no terceiro mês de armazenamento. A análise de correlação entre o peso seco das sementes (r = -0,80) e o teste frio (r = 0,76) com a emergência de plântulas em campo foi significante a 1% de probabilidade.

Gliricidia sepium is a drought-tolerant species, easily multiplied by seeds, and has been exploited by farmers as a source of forage in the semi-arid region of northeast Brazil. The objective of the present study was to evaluate the effect of seed storage on the mobilization of reserves during imbibition of "Gliricidia" seeds. Freshly-harvested seeds were packed in kraft paper bags and stored for three and six months in the laboratory under ambient conditions (25 º C ± 3 T and 75% ± 3 RH). Cotyledons were isolated from imbibed seeds and macerated for the extraction and quantification of total soluble sugars, reducing sugars, sucrose and starch, as well as of proteins, amino acids and for amylase activity. Storage under these conditions resulted in an increase in seed water content although germination remained at relatively high levels (86%). Seed macromolecule levels showed significant variation with the storage period and imbibition and these variations were associated with a loss in seed viability due to inadequate storage conditions. Gliricidia sepium é uma espécie que apresenta resistência à seca e facilidade em se propagar por sementes, sendo intensamente explorada como forrageira no semi-árido nordestino. O presente estudo foi desenvolvido para avaliar o efeito do armazenamento na mobilização de açúcares e proteínas e as possíveis modificações dessas macromoléculas de reserva durante a germinação de sementes de gliricidia. Sementes recém coletadas foram armazenadas por três e seis meses em sacos de papel kraft à temperatura ambiente (25 ºC ± 3 T e 75% ± 3UR). Os cotilédones das sementes embebidas foram extraídos e macerados para a quantificação dos açúcares solúveis totais, açúcares redutores, sacarose, amido, proteínas, aminoácidos e atividade enzimática. O armazenamento em embalagem de papel kraft em temperatura ambiente propiciou o aumento no teor de água embora a capacidade germinativa fosse mantida em níveis altos (86%). O armazenamento e o tempo de embebição influenciaram os níveis de macromoléculas nas sementes. A variação nos teores de macromoléculas esta associada com a perda da viabilidade das sementes proporcionada pela condição inadequada de armazenamento.

A catingueira (Caesalpinia pyramidalis Tul.) é uma espécie nativa da caatinga dotada de grande resistência à seca e de grande potencial econômico. No entanto, não existem informações sobre o desenvolvimento dessa espécie em diferentes substrates e luminosidade, fatores ambientais que mais influenciam a produção de seedlings florestais. Dessa forma, este trabalho teve por objetivo avaliar o efeito de diferentes níveis de shading e tipos de substrates nas taxas de crescimento de mudas de catingueira. O experimento foi conduzido na Universidade do Estado da Bahia e na Embrapa Semiárido, Petrolina, PE. As sementes foram semeadas em recipientes preenchidos com diferentes substratos: solo, areia, solo+areia, solo+areia+esterco caprino e substrato comercial, sendo os recipientes mantidos em quatro diferentes sombreamentos, a céu aberto (sem sombreamento) e em telados tipo sombrite de 30%, 50% e 75% de sombreamento. Aos 30, 60 e 100 dias após a estabilização da emergência das plântulas, as mudas foram avaliadas quanto à taxa de crescimento absoluto, taxa de crescimento relativo, taxa assimilatória líquida, razão de área foliar,área foliar específica, peso específico da folha e razão de peso foliar. Não houve interação significativa entre os dois fatores estudados em nenhuma das taxas de crescimento calculadas. Nas condições deste trabalho, foi possível concluir que as taxas de crescimento das mudas de catingueira, em geral, não foram influenciadas pela luminosidade às quais elas foram submetidas e que solo coletado em região de caatinga, combinado ou não, com areia e esterco, possibilitou maior crescimento das mudas. Caesalpinia pyramidalis Tul. is a native species from the caatinga biome, with a great resistance to drought and great economic potential. However, there is no information regarding the development of this species under different substrates and light intensities, the major environmental factors that influence forest seedling growth. The objective of this work was to evaluate the effect of different shadings and substrates on the growth rates of C.pyramidalis seedlings. The experiment was carried out at the Universidade do Estado da Bahia and Embrapa Semi-Árido. The seeds were sowed in recipients filled with different substrates: soil, sand, soil+ sand, soil+ sand+ goat manure and commercial substrate. The recipients were maintained under different shadings: sunlight (no shading) and at 30%, 50% and 75% shadings. 30 , 60 and 100 days after the emergence stabilization, the seedlings were evaluated as to the absolute growth rate, relative growth rate, net assimilation rate, leaf area ratio, specific leaf area, specific leaf weight and leaf weight ratio. There was no interaction between the two studied factors for any growth rate. Under the conditions of this work, it is possible to conclude that, in general, the growth rates of C.pyramidalis seedlings were not influenced by shading and that the soil collected in the caatinga region, associated or not, to sand and manure, allowed a higher growth.

The aim of this study was to evaluate the effects of storage conditions on the germination of A. cearensis seeds. The experimental design was completely randomized into split plots over time with four replicates. The storage conditions of the airtight containers in the refrigerator and laboratory, paper bags in the laboratory and liquid nitrogen were assessed for 27 months. In the laboratory, we evaluated the germination, the germination rate, uniformity of germination, and total soluble and reducing sugars in the radicle. In the greenhouse, we evaluated seedling emergence, emergence rate and height of 30-day-old seedlings. Seeds stored in the refrigerator maintained a high initial germination rate, which decreased from the 21st month. Seeds stored in paper bags in the laboratory showed low emergence and small seedlings. Total soluble sugars and reducing sugars were mobilized when the seeds were stored at low temperatures. Thus, it is not advisable to store A. cearensis seeds in a laboratory environment without airtight containers. A. cearensis seeds kept in a refrigerated environment maintained their viability for at least two years. Resumo: O objetivo deste trabalho foi avaliar os efeitos das condições de armazenamento sobre a germinação de sementes de A. cearensis. O delineamento experimental foi inteiramente casualizado em parcelas subdivididas ao longo do tempo com quatro repetições. As condições de armazenamento como recipiente hermético no refrigerador; recipiente hermético em laboratório, sacos de papel em laboratório e nitrogênio líquido foram avaliadas durante 27 meses. No laboratório foram avaliadas germinação, taxa de germinação, uniformidade de germinação, açúcares solúveis totais e redutores da radícula. Em casa de vegetação avaliou-se emergência das plântulas, taxa de emergência e altura de mudas no decorrer dos 30 dias. As sementes armazenadas no refrigerador mantiveram alta germinação inicial e diminuíram a partir do 21º mês. O armazenamento de sementes em sacos de papel em laboratório apresentou baixa emergência e menores mudas. Os açúcares solúveis totais e os açúcares redutores são mobilizados quando as sementes são armazenadas a baixas temperaturas. Não é aconselhável armazenar sementes de A. cearensis em ambiente de laboratório sem um recipiente hermético. As sementes de A. cearensis mantidas em ambiente refrigerado mantêm a viabilidade durante pelo menos dois anos.