RESUMO: Considerando as potencialidades e importância da biodiversidade do bioma Caatinga, estudos sobre espécies endêmicas são relevantes para conservação de seus recursos naturais. Objetivou-se com este trabalho avaliar a viabilidade e a superação de dormência de sementes de juazeiro (Ziziphus joazeiro Mart.) e seu o crescimento inicial em diferentes tipos de solo. Os experimentos foram conduzidos em três etapas. Na primeira, avaliou-se a viabilidade de diferentes lotes de sementes, utilizando o teste de tetrazólio. A segunda etapa foi conduzida em viveiro, avaliando-se as aplicações de processos físicos, escarificação com lixa e com martelo, para superação da dormência das sementes e determinação do crescimento inicial das plantas. Na última etapa foram avaliados os índices de clorofila a e b, as trocas gasosas e o acúmulo de matéria seca em plantas jovens de juazeiro em três tipos de solo (Latossolo, Neossolo e Vertissolo). A partir dos resultados obtidos pode-se afirmar que a viabilidade das sementes de juazeiro é bastante influenciada pelas diferenças existentes entre plantas matrizes e pelas condições de armazenamento, apresentando longevidade de dois anos, quando armazenadas a 22 oC e 16% de umidade relativa. Os métodos de escarificação com lixa e martelo não são eficientes para reduzir o tempo e uniformizar a geminação das sementes. As plantas de juazeiro apresentam elevado potencial para se desenvolver em diferentes ambientes edáficos, adaptando-se bem a solos com diferentes texturas e composições químicas. | ABSTRACT: Considering the potential and importance of biodiversity of the Caatinga biome, studies on endemic species are relevant to conservation of its natural resources. The objectives of this work was to evaluate seed viability and physical methods for overcoming seed dormancy in juazeiro (Ziziphus joazeiro Mart.) and assess the influence of different types of soil on the initial growth of juazeiro plants. The experiments were conducted in three stages. In the first stage, the viability of seeds from different lots was evaluated using the tetrazolium test. The second stage was conducted in a plant nursery, evaluating the application of physical processes (scarification with sandpaper and hammer) in overcoming seed dormancy, and the initial growth of the plants. In the third step, the chlorophyll a and b contents, gas exchange and dry matter accumulation were evaluated in young juazeiro plants in three types of soil (Oxisol, Entisol and Vertisol). The results indicate that the viability of juazeiro seeds is greatly influenced by differences between the progenitor plants and by storage conditions, which enable a longevity of two years when stored at 22°C and 16% of relative humidity. The scarification methods with sandpaper and hammer are not efficient to reduce the time and uniform seed germination. The juazeiro plants have high growth potential in different edaphic environments, adapting well to soils of different textures and chemical compositions.

Considering the potential and importance of biodiversity of the Caatinga biome, studies on endemic species are relevant to conservation of its natural resources. The objectives of this work was to evaluate seed viability and physical methods for overcoming seed dormancy in juazeiro (Ziziphus joazeiro Mart.) and assess the influence of different types of soil on the initial growth of juazeiro plants. The experiments were conducted in three stages. In the first stage, the viability of seeds from different lots was evaluated using the tetrazolium test. The second stage was conducted in a plant nursery, evaluating the application of physical processes (scarification with sandpaper and hammer) in overcoming seed dormancy, and the initial growth of the plants. In the third step, the chlorophyll a and b contents, gas exchange and dry matter accumulation were evaluated in young juazeiro plants in three types of soil (Oxisol, Entisol and Vertisol). The results indicate that the viability of juazeiro seeds is greatly influenced by differences between the progenitor plants and by storage conditions, which enable a longevity of two years when stored at 22°C and 16% of relative humidity. The scarification methods with sandpaper and hammer are not efficient to reduce the time and uniform seed germination. The juazeiro plants have high growth potential in different edaphic environments, adapting well to soils of different textures and chemical compositions.