-(How and why to measure the germination process?). In the last two centuries, papers have been published including measurements of the germination process. High diversity of mathematical expressions has made comparisons between papers and some times the interpretation of results difficult. Thus, in this paper is included a review about measurements of the germination process, with an analysis of the several mathematical expressions included in the specific literature, recovering the history, sense, and limitations of some germination measurements. Among the measurements included in this paper are the germinability, germination time, coefficient of uniformity of germination (CUG), coefficient of variation of the germination time (CV t ), germination rate (mean rate, weighted mean rate, coefficient of velocity, germination rate of George, Timson's index, GV or Czabator's index; Throneberry and Smith's method and its adaptations, including Maguire's rate; ERI or emergence rate index, germination index, and its modifications), uncertainty associated to the distribution of the relative frequency of germination (U), and synchronization index (Z). The limits of the germination measurements were included to make the interpretation and decisions during comparisons easier. Time, rate, homogeneity, and synchrony are aspects that can be measured, informing the dynamics of the germination process. These characteristics are important not only for physiologists and seed technologists, but also for ecologists because it is possible to predict the degree of successful of a species based on the capacity of their harvest seed to spread the germination through time, permitting the recruitment in the environment of some part of the seedlings formed.Key words -germinability, germination rate, germination synchrony, germination time, germination uniformity RESUMO -(Como e por que medir o processo de germinação?). Nos dois últimos séculos, trabalhos têm sido publicados incluindo medidas do processo de germinação. A diversidade das expressões matemáticas existente na literatura tem tornado difícil comparações entre os trabalhos e, algumas vezes, a interpretação dos resultados. Assim, este trabalho apresenta uma revisão sobre medidas de germinação, incluindo a análise de várias expressões matemáticas contidas na literatura específica. Entre as medidas analisadas estão a germinabilidade, tempo de germinação, coeficiente de uniformidade de germinação (CUG), coeficiente de variação do tempo de germinação (CV t ), velocidade de germinação (velocidade média, velocidade média ponderada, coeficiente de velocidade, velocidade de germinação de George, índice de Timson, GV ou índice de Czabator; método de Throneberry e Smith e suas adaptações, incluindo a velocidade de Maguire; ERI ou índice de velocidade de emergência, índice de germinação e suas modificações), incerteza associada à distribuição das freqüências relativas de germinação (U) e índice de sincronia (Z). Os limites dessas medidas foram incluídos para facilitar a interpretação...

-(Calculating germination measurements and organizing spreadsheets). With the objective to minimize diffi culties for beginners we are proposing the use of a conventional spreadsheet for the calculations of the main germination (or emergence) measurements, the organization of the fi nal data for the statistical analysis and some electronic commands involved in these steps.Key words -germination rate, germination time, seed germination, synchrony, uncertainty RESUMO -(Calculando medidas de germinação e organizando planilhas eletrônicas). Com o objetivo de minimizar as difi culdades dos iniciantes, estamos propondo o uso de planilhas eletrônicas convencionais para o cálculo das principais medidas de germinação (ou emergência), a organização dos dados fi nais para a análise estatística e alguns comandos eletrônicos envolvidos nesses passos.Palavras-chave -germinação de sementes, incerteza, sincronia, tempo de germinação, velocidade de germinação

-(Anacardium humile A. St.-Hil. (Anacardiaceae) seedling emergence evaluated by means of small samples). Anacardium humile has low capacity for fruit production, limiting the application of experimental techniques, broadly used in the analysis of seed germination. Thus, the purpose of this paper was to introduce the statistical theory of small samples to the study of the seedling emergence of this species. Cashew nuts of different individuals were randomly collected, being submitted to scarification by abrasion of the pericarp near the pedicel; scarification in the same manner followed by washing in water for 24 hours, and intact cashew nuts as control treatment. The cashew nuts (50 per treatment) were sowed at 1 cm depth, in vermiculite moistened with distilled water at field capacity. The experiment was carried out under continuous fluorescent white lamps (21.8 μmol m -2 s -1 ), at 25 ºC. The emergence (%) presented approximated normal distribution for all treatments and they did not differ significantly by Student t test (emergence between 70% and 76%). Seedlings emerged from scarified cashew nuts washed in water presented shorter mean emergence time (16.3 days) and consequently higher mean emergence rate (0.0613 day -1 ) in relation to the other treatments. The uncertainty values far from zero (I ≥ 3.28 bits) and values of Z near zero (Z ≤ 0.095) indicated low seedling emergence synchrony for this species. The results obtained showed that by using reduced number of cashew nuts it was possible to infer about seedling emergence process without violation of the statistical principles and assumptions.Key words -cashew nut, emergence measurements, normal distribution, Student t test RESUMO -(Emergência de plântulas de Anacardium humile A. St.-Hil. (Anacardiaceae) avaliada por meio de amostras pequenas). Anacardium humile possui baixa capacidade de produção de frutos, o que limita a aplicação de técnicas experimentais, amplamente utilizadas na análise da germinação. Assim, o objetivo do trabalho foi introduzir a teoria estatística de amostras pequenas ao estudo da emergência de plântulas da espécie. Núculas foram aleatoriamente coletadas de diferentes indivíduos, sendo submetidas à escarificação por abrasão do pericarpo na região junto ao pedicelo; escarificação na mesma região, seguida de lavagem em água corrente por 24 horas e núculas intactas como controle. As núculas (50 por tratamento) foram semeadas a 1 cm de profundidade, em vermiculita umedecida com água destilada à capacidade de campo, contida em bandejas de plástico. O teste de emergência foi conduzido sob luz branca fluorescente contínua, a 21,8 μmol m -2 s -1 e 25 ºC. O percentual de emergência apresentou distribuição normal aproximada para todos os tratamentos que, quando comparados pelo teste t de "Student", não diferiram significativamente (emergência entre 70% e 76%). Plântulas emergidas a partir de núculas escarificadas e posteriormente lavadas apresentaram menor tempo médio (16,3 dias) e conseqüentemente maior velocidade média de emergên...

No abstract

The soil spore bank of ferns is a biotic component of plant communities, important for regeneration processes, population dynamics, and conservation programs. Each year it is enriched when new units are incorporated, and impoverished when they are lost by predation, loss of viability, or by germination. Soil was collected in three microhabitats of the gallery forest of the Panga Stream, at four depths, in the wet and the dry seasons. In general, independent of the season, 'dike' samples presented lower numbers of viable spores when compared to samples from the 'middle' and 'edge' of the forest. The number of viable spores and the number of fern species represented decreased with depth. At the end of the dry season, the number of viable spores decreased only in the first centimeters of the soil. Viable spores of thirteen terrestrial species were registered in the soil of this gallery forest. The presence of viable spores in the soil after six months drought and in deeper soil layers shows the existence of a persistent soil spore bank in the gallery forest of the Panga Stream.A diaspore bank is a biotic component of soil where dispersion units in quiescence or dormancy are found. This biological store can be enriched or impoverished each year, when new units are incorporated, or lost by predation, loss of viability, or germination. Therefore, the diaspore bank is a dynamic component that represents a continuous source of dispersion units important for regeneration processes and population dynamics of plant communities. It is this biological and genetic potential in the soil which permits the local survival of the species during unfavorable environmental conditions or disturbances.Most of the information about diaspore banks is related to the soil seed banks of plant communities (

-(Germination of newly collected diaspores of Myracrodruon urundeuva Allemão (Anacardiaceae) occurring in the cerrado of Central Brazil). Myracrodruon urundeuva occurs in Northeast, Southeast, and West Center Brazilian regions, being considered as a vulnerable species to extinction. Diaspores collected in the Araguari River valley, MG, were used in three experiments, in a completely randomized design, with five replications of 50 diaspores each one. In the first and second experiments, germination boxes with vermiculite moistened with distilled water, GA 3 and cytokinin at 1, 10, 100 µg mL -1 , and 0.2% KNO 3 were used as treatments. The first experiment was conducted under continuous fluorescent white lamps and the second in darkness. In the third experiment the diaspores were moistened with distilled water and stratified during one to six days at 4-5 °C in darkness. Control treatment was constituted by diaspores moistened with water, without stratification. For the experiments conducted under light conditions, data were collected observing the embryo protrusion every 24 hours; in darkness conditions counting was processed after seven days from the beginning of the experiment. Under continuous light, diaspores treated with 1 µg.mL -1 GA 3 were more homogeneous (CV t = 17.13%) and synchronized (Z = 0.64) in relation to the other treatments. The germinability ranged from 52.8% to 60% and occurred between two and three days. In darkness condition, germinability ranged from 50.4% to 58.8% and under stratification, from 49.6% to 61.2%. For the experiment testing stratification, the lowest mean time, the highest rate and germination uniformity were registered for diaspores stratified during six days. Although the germination process had been fast, low germinability indicates that new investigations are necessary to the sustainable exploration of this species.Key words -germination measurements, growth regulators, stratification RESUMO -(Germinação de diásporos recém-colhidos de Myracrodruon urundeuva Allemão (Anacardiaceae) ocorrente no cerrado do Brasil Central). Myracrodruon urundeuva distribui-se no nordeste, sudeste e centro-oeste brasileiro, sendo considerada uma espécie vulnerável à extinção. Diásporos coletados no vale do Rio Araguari, MG, foram utilizados em três experimentos, em delineamento inteiramente casualizado, cada um deles com cinco repetições de 50 diásporos. No primeiro e segundo experimentos, utilizou-se gerbox com vermiculita umedecida com água destilada, GA 3 e citocinina a 1, 10, e 100 µg.mL -1 e KNO 3 a 0,2%, o primeiro mantido sob luz branca fluorescente contínua e o segundo no escuro. No terceiro experimento, os diásporos foram umedecidos com água e estratificados por um a seis dias a 4-5 °C, no escuro; no controle os diásporos não foram estratificados. A cada 24 horas observou-se a protrusão do embrião nos experimentos mantidos sob luz e, aos sete dias, na ausência de luz. Sob luz contínua, diásporos tratados com GA 3 1 µg.mL -1 foram mais homogêneos (CV t = 17,13%) e sincronizados...

Studies on diaspore germination in native species with low economic relevance but great ecological significance have been based on a wide range of sample sizes. However, can the sample size change the physiological inferences made from germination measurements? To answer this question, diaspores of six Cerrado species were evaluated for germinability, germination time (initial, mean, and final), germination velocity (mean germination rate and Maguire’s rate), coefficient of variation of the germination time, and synchronization index of the germination process. Germinability, final time, mean time, and synchronization index were robust with respect to sample size fluctuation. Maguire’s rate, initial time, coefficient of variation of the germination time, and mean germination rate, in contrast, were affected by sample size fluctuation, at least in one of the species tested. The robustness of the time measurements and the synchronization index also demonstrates that the germination process occurs in a cadenced rhythm, much like a biological clock. Among the measurements evaluated, Maguire’s rate is the only one that must be avoided, since it is strongly influenced by sample size and by the balance between germinability and mean germination rate. These results demonstrate that sample size can affect inferences about the germination process and can compromise restoration and (or) conservation efforts.

RESUMOÉ comum encontrar na literatura trabalhos sobre germinação de sementes nativas de uma mesma espécie com tamanhos de amostra diferenciados. No entanto, não se sabe quais são as consequências disso para os resultados obtidos. Assim, objetivou-se estudar o comportamento das medidas de germinação frente à variação do número de sementes que compõe a amostra para Bowdichia virgilioides. O experimento foi conduzido em câmara de germinação, sob luz branca fluorescente contínua, a 26,2 ± 2,5 ºC. O delineamento utilizado foi o inteiramente casualizado, em esquema fatorial 3 x 3 (três tamanhos de amostra x três lotes), com número de repetições fixo e igual a quatro. A semeadura foi realizada em caixas tipo gerbox, contendo 25, 50 ou 100 sementes, perfazendo 100, 200 ou 400 sementes por amostra. A germinabilidade, tempo inicial, médio e final, velocidade média e VE (IVG), coeficiente de variação do tempo, incerteza e sincronia da germinação foram avaliados, sendo consideradas germinadas as sementes com protrusão de embrião. Gráficos de frequência relativa também foram construídos. Dentre estas medidas, as mais frágeis ao incremento do tamanho da amostra foram o VE e a incerteza. O VE, além de ser influenciado pelo tamanho da amostra, também foi influenciado pelo contrabalancear entre germinabilidade e velocidade média, demonstrando ser uma medida imprópria para mensurar velocidade de germinação quando a capacidade germinativa dos lotes for diferente. As medidas de tempo, uniformidade, sincronia, velocidade média e a germinabilidade não tiveram seus resultados afetados pelos diferentes tamanhos da amostra. A germinabilidade, entretanto, mostrou-se a medida mais estável do processo germinativo, não sendo influenciada pelo tamanho da amostra, mesmo quando analisada por meio de lotes com qualidades muito discrepantes. Palavras-chave: teste de germinação; qualidade fisiológica; sucupira-preta; tamanho ótimo de amostra. ABSTRACTIt is usual to find papers about seed germination of native species using different sample sizes. However, the consequences of these procedures on the results are unknown. This study measured the germination process of Bowdichia virgilioides based on different seed sample sizes. The assay was conducted in a germination chamber under continuous fluorescent white lamps and 26.2 ± 2.5 ºC. The design was completely randomized, as a 3 x 3 factorial (three sample sizes x three seed lots), with four replications per treatment. The sowing was done in gerbox, each one containing 25 seeds, making up 100, 200 and 400 seeds per sample analyzed. Germinability, time (first, average and final), speed (mean germination rate and Maguire's index -VE or IVG), coefficient of variation of the germination time, uncertainty and synchrony of the germination process were evaluated. Those seeds with embryo protrusion were considered germinated. Germination relative frequency graphics were also made. Among these measurements, the most fragile to