Environmental factors affect the germination process, like the presence of seed coat and the quality of light; these informations are still scarce for many native species from Brazil, especially for Senna cana, which there are no adequate standards and methodologies to be used in germination tests. The aim of this research was to recommend adequate pre-germinative treatment(s) to overcome seed dormancy, and determine the degree of influence of different light regimes in seed germination of S. cana. Two experiments were carried out: T1-evaluation of different methods of dormancy overcoming (intact seeds (control), T2-imbibition of the intact seeds for 24 hours (in distilled water), T3-scarified seeds with sandpaper n° 100 in the hilum opposite region, T4-scarified seeds with sandpaper n° 100 in the region the hilo opposite region and imbibition in water (in distilled water) for 24 hours; T5-imbibition in water at 80°C); 2-Influence of light quality on seed germination and vigor (white light, red light, far red light and absence of light). The evaluated parameters were: first JEAI, 32(5): 1-9, 2019; Article no.JEAI.47671 2 germination count, percentage of germination, IVG (Germination speed index), MGT (Mean germination time). Treatments were compared by Tukey at 5% probability. The best method for overcoming seed dormancy was mechanical scarification with sandpaper nº 100. The germination of the seeds of S. cana can be classified as indifferent to the luminosity, despite germinative response be greater under white and red light. Original Research Article

RESUMOO estudo avaliou a composição e riqueza florística do banco de semente em área de caatinga. Foram arranjadas sistematicamente 35 parcelas 10 x 10 m e coletadas, aleatoriamente, amostras de solo com. Cada amostra foi homogeneizada e colocada para germinar em dois ambientes: pleno sol e sombra a 50%. Foram encontrados 237 indivíduos, pertencentes a 13 famílias botânicas, 22 gêneros e 26 espécies. A densidade total do banco de sementes foi de 43 sementes/m 2 . O tratamento sombra apresentou densidade de 33,2 sem/m 2 , com maior diversidade de indivíduos. Já o tratamento a pleno sol, obteve densidade de 9,28 sem/m 2 . O ambiente sob sombrite proporcionou maior germinação e sobrevivência inicial de plântulas. PALAVRAS-CHAVE:Regeneração, riqueza florística, recuperação ambiental. ABSTRACTThe study evaluated qualitatively and quantitatively the seed bank of an area of caatinga. 35 plots were systematically arranged 10 x 10 m, samples were randomly collected. Each sample was individually homogenized and placed to germinate in two environments: full sun and shade to 50%. Was recorded 237 individuals belonging to 13 families and 26 species were identified. The total density of the seed bank was approximately 43 seeds/m2. The treatment with shade showed a density of 33.2 seed/m2. The treatment in full sun got density of 9.28 seed/m2. The environment under shade got more seed germination and initial survival of seedlings.

This study aimed to quantify the tannic content of the barks and fruit of angico-vermelho, jurema-preta and acacia-negra using skin powder as detanizador agent. Materials from these species were ground and classified, with 12.5g of air dried particles subjected to extraction using a steam jacket type extractor to obtain 1000 ml of solution, using a completely randomized analytic design. The solution was evaluated using four treatments: angico bark; jurema bark; acacia bark and angico fruit. Three replicates per treatment were realized and subrepetitions were analyzed in triplicate. The results were interpreted by comparison of means with Tukey test at 5% significance. Best results in terms of total solids content, were observed in acacia bark (67.2%), differing statistically for angico bark (63.5%). The soluble solids content, in turn, was superior to angico bark (60.3%), differing statistically from acacia bark (49.8%). No statistically significant differences for tannin content were observed between acacia and angico barks, which presented values of 28.4 and 26.8%, respectively.

This research aimed to determine the concentration of tannins in the bark and in the branches of ten species of Caatinga occurrence. The Folin-Denis colorimetric method was used to determine the phenol content and the tannins are precipitated using a protein. The tannin content was obtained by the difference between the supernatant and the non-tannic phenol content. The data were subjected to the Shapiro-Wilk normality’s test and after, to Analysis of Variance using a 2x10 factorial design and Turkey’s test was used to detect differences. For bark sample, the species Parapiptadenia zehntneri, Parapiptadenia rigida and Libidibia ferrea presented the three highest percentages among the studied species, being 10.84%, 10.74% and 10.27%, respectively. For branch sample, Aspidosperma pyrifolium presented the highest percentage of tannins among the ten species, with 9.15% of these substances. It is possible to suggest the use of other parts of the tree to extract the tannins, such as the branches and their bark, offering an alternative for the extraction that is usually made from the main trunk and providing sustainability to the Caatinga.