Seed size and presence of thorns in Caryocar brasiliense on seedling emergence

Commercial propagation of pequizeiro, which stands out among the main native fruits of the Cerrado region for its high economic potential, has been done by seeds, despite their erratic germination. The objective of this study was to evaluate the effect of seed size and presence of thorns on the endocarp on seedling emergence of pequizeiro in the field. Seeds were collected in a pequizeiro commercial area in Canarana-MT, Brazil. Due to availability, 2,353 thorny seeds (3 sizes) and 106 seeds without thorns (medium sized) were tested. Thorny seeds were classified as large ­ longer than 50 mm; medium ­ between 40 and 50 mm; small ­ less than 40 mm. Seedling emergence started after 50 days in all seed categories, extending up to 100 days in the large seeds and to about 1 year after sowing in the small and medium sized ones. Small seeds showed a lower rate and speed of emergence compared to the others. Large seeds showed higher emergence speed compared to the medium ones. The presence of thorns did not affect seedling emergence. These results indicate the advantages of pequizeiro seed classification for sowing purposes.

Genome-wide association study of pre-harvest sprouting resistance in Chinese wheat founder parents

Abstract Pre-harvest sprouting (PHS) is a major abiotic factor affecting grain weight and quality, and is caused by an early break in seed dormancy. Association mapping (AM) is used to detect correlations between phenotypes and genotypes based on linkage disequilibrium (LD) in wheat breeding programs. We evaluated seed dormancy in 80 Chinese wheat founder parents in five environments and performed a genome-wide association study using 6,057 markers, including 93 simple sequence repeat (SSR), 1,472 diversity array technology (DArT), and 4,492 single nucleotide polymorphism (SNP) markers. The general linear model (GLM) and the mixed linear model (MLM) were used in this study, and two significant markers (tPt-7980 and wPt-6457) were identified. Both markers were located on Chromosome 1B, with wPt-6457 having been identified in a previously reported chromosomal position. The significantly associated loci contain essential information for cloning genes related to resistance to PHS and can be used in wheat breeding programs.

Effects of fluridone, gibberellin acid and germination temperature on dormancy-breaking for Epimedium wushanense / 中国中药杂志

We introduced Epimedium wushanense seed which has been stratified for 90 days at 10/20 ℃ as experimental materials, with which we studied the effects of fluridone, gibberellin acid and temperature on E. wushanense germination. The results were suggested as shown below. ①Temperature, fluridone and gibberellin acid can both solely or jointly affect germination energy, germination rate significantly. Among those factors, fluridone affect germination rate and germination energy the most, followed by gibberellin acid and temperature. The highest germination rate under 4 ℃ and 10/20 ℃ stratification are 79.3%, 72.0% respectively, which resulted from treatment of F10GA300 and F20GA200 respectively. The highest germination energy under 4 ℃ and 10/20 ℃ stratification are 52.7%, 52.0%, respectively, which both resulted from F20GA200. ②Compared with 4 ℃ germination, seed could not germinate at 10/20 ℃ germination. Nontheless, application of fluridone can lead E. wushanense seeds to germinating.③The effects of gibberellin acid and interaction between gibberellin acid and fluridone significantly affect seed rotten rate during germination. In addition, soaking is another remarkable factor which increased seed rotten rate. As a result, it is feasible to promote E. wushanense dormancy releasing with gibberellin acid and fluridone associating with a proper germination temperature. Further, it is necessary taking actions to avoid seed rotten rate for saving E. wushanense nurseries'cost.

Study on Standardization of Germination Test of Astragalus membranacus Seed / 中国药房

OBJECTIVE:To select the optimum conditions for germination test of Astragalus membranaceus seed and provide reference for the formulation of testing rules of A. membranaceus seed. METHODS:First,the dormancy of A. membranaceus seeds were broken by soaking seed with 98% H2SO4 for 30 min and 35 ℃ warm water for 9 h,then treated with different temperatures of germination,different germinating beds and light conditions. Different treatment methods were evaluated by germination rate, germination potential and germination index. RESULTS:With the increase of temperature,germination rate,germination potential and germination index decreased. At 30 ℃,germination rate,germination index,and germination potential were significantly low-er than those of seed with other treatments,in which the germination rate was the highest at 15℃;but there wasn’t significant dif-ference in germination rate of 15 ℃ and 20 ℃. There were no significant differences in germination rate of different germination beds,but sand bed could restrain bacterial growth well. Under both light and dark conditions,seed could normally germinate. The appropriate condition of A. membranacus seed germination was at 15 ℃,sand bed and dark. The germination rate,germination po-tential and germination index were(98.5±0.65)%,(85.5±0.87)%and 175.8±2.31,respectively. Meanwhile,the germination pe-riod was only 4 days. CONCLUSIONS:Suggested quality control method of A. membranaceus seed is that at 15 ℃,sand bed and dark. The second day of germination as initial counting time and forth day as the last counting time are used to calculate germina-tion index. This method is easy and controllable. It also has short germination period and high germination rate.

Cloning and sequence analysis of PqGA20ox gene in Panax quinquefolium / 中草药

Objective: To clone and analyze the coding region of gibberellin 20-oxidase (GA20ox) gene of Panax quinquefolium in seed dormancy and germination process. Methods: According to P. quinquefolium seeds transcriptome annotation, one transcript coding of GA20ox was obtained by comparative analysis of nine related unigenes. The full-length cDNA of PqGA20ox was determined by using RT-PCR method. Then the bioinformatic analysis of this gene and encoded protein was performed. The expression level of PqGA20ox in the roots, stems, leaves, and several seed dormancy periods was detected by real time fluorescent quantitative PCR (RT-qPCR). Results: Bioinformatic analysis showed that PqGA20ox contained 1092 bp and encoded 363 amino acids. PqGA20ox encoded protein had neither transmembrane nor signal peptide. The expression level of PqGA20ox was higher in the inset periods of morphological and physiological dormancy than that in the other periods based on RT-qPCR analysis. Conclusion: The PqGA20ox gene is cloned for the first time, and will provide a foundation for the dormancy release molecular mechanism of P. quinquefolium.

Effect of seed coat on the seed germination and seedling development of Calophyllum brasiliense Cambess. (Clusiaceae) / Efeito do envoltório na germinação da semente e no desenvolvimento de plântulas de Calophyllum brasiliense Cambess. (Clusiaceae)

This work aimed to study the effect of the Calophyllum brasiliense seed coat on the seed germination process. To this end, three experiments were conducted in laboratory, greenhouse and screenhouse. From a total of six treatments, five are related to the seed coat (mechanical scarification; mechanical scarification followed by 2 hours in water, chemical scarification, hot water immersion and complete seed coat removal) and one control. Laboratory and greenhouse experiments were conducted in a completely randomized design (CRD). Screenhouse experiment was conducted in a completely randomized block design (RBD). We evaluated the total percentage, the speed index and the average time of germination or emergence. Data were subjected to analysis of variance and means compared by LSD test, at 5%. Under the conditions of this work, it was possible to infer that, in laboratory, mechanical scarification followed by 2 hours in water increases the proportion and germination speed index (GSI), in the greenhouse, the complete seed coat removal increases the percentage and emergence speed index (ESI), and in the screenhouse, mechanical scarification followed by 2 hours in water and chemical scarification presented the best results. The average germination time was not significantly different in the three experiments evaluated.

Objetivou-se com este trabalho estudar o efeito do envoltório da semente de Calophyllum brasiliense no processo de germinação. Foram montados três experimentos, sendo estes conduzidos em laboratório, casa de vegetação e telado. Avaliaram-se seis tratamentos, sendo cinco relacionados ao envoltório (escarificação mecânica; escarificação mecânica seguido por 2h em água; escarificação química; imersão em água quente; e retirada total do envoltório) e a testemunha. Os experimentos em laboratório e casa de vegetação foram conduzidos em delineamento inteiramente casualizado. No telado, o experimento foi conduzido em delineamento em blocos casualizados. Avaliaram-se a percentagem total; o índice de velocidade e o tempo médio de germinação ou emergência. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste t (LSD) a 5% de probabilidade. Foi possível inferir que no laboratório, a escarificação mecânica, seguido por 2h em água, aumenta a percentagem e o índice de velocidade de germinação (IVG); na casa de vegetação, a retirada total do envoltório aumenta a percentagem e o índice de velocidade de emergência (IVE); e no telado, a escarificação mecânica, seguida por 2h em água, e a escarificação química apresentam os melhores resultados. O tempo de germinação não apresentou diferença significativa nos três experimentos avaliados.

Cloning and sequence analysis of PqGA2ox gene in Panax quinquefolium / 中草药

Objective: To clone and analyze the gibberellin 2-oxidase (GA2ox) gene of Panax quinquefolium in seed germination. Methods: Gene sequences about gibberellins synthesis and catabolism were found out from annotation information of 78 207 unigenes obtained by high-throughput sequencing in the early study. Then one transcript coding GA2ox was obtained from 11 unigenes related to GA2ox. Primers were designed according to selected sequence to get the full-length cDNA of P. quinquefolium using PCR method. Predictive analysis and expression analysis of PqGA2ox were obtained by bioinformatics and real-time PCR. Results: A GA2ox gene containing 987 bp encoding 328 amino acids was cloned and named as PqGA2ox. Bioinformatics analysis showed that PqGA2ox had no transmembrane domain or signal peptide, but had the 20G-Fell_Oxy conserved domains. The expression level of PqGA2ox was lower in the metaphase of morphological dormancy and physiological dormancy than that in the intitial period and release period based on real-time PCR analysis. Conclusion: The PqGA2ox gene from the seeds of P. quinquefolium is cloned for the first time, which will provide a foundation for the molecular mechanism of dormancy release of P. quinquefolium.

Synergistic effect of stratification and gibberellic acid on breakage of seed dormancy of Paris polyphylla var. Yunnanensis / 中国药学杂志

OBJECTIVE: To explore the synergistic effect of stratification and gibberellic acid on the germ-free germination and plant morphogenesis of Paris polyphylla var. Yunnanensis seeds. METHODS: The synergistic effect of stratification and gibberellic acid on the germ-free germination and plant morphogenesis of Paris polyphylla var. Yunnanensis seeds was studied. The activities of peroxidase(POD) and catalase(CAT) of Paris polyphylla var. Yunnanensis seeds during the germ-free culture process were determined. RESULTS: Soaking the seeds of Paris polyphylla var. Yunnanensis using 50 mg · L-1 gibberellic acid could not break seed dormancy. Stratification could break the morphologic dormancy of seeds, however, it could not break the physiological dormancy, so the seeds could not germinate. The synergy between stratification and gibberellic acid not only broke the morphologic dormancy, but also broke the physiological dormancy. The seed germination efficiency and radicle length under the synergy between wet sand stratification and gibberellic acid, which were 68.67% and (3.80 ± 0.200) cm respectively, were higher than those under the synergy between dry sand stratification and gibberellic acid (P < 0.05). During the germ-free culture process of Paris polyphylla var. Yunnanensis seeds, with the dormancy being released, the activities of POD and CAT in the seeds were positively correlated with the seed sprouting, germination, growth and development. CONCLUSION: This study preliminarily ascertains the synergistic effect of stratification and gibberellic acid on the germ-free germination and plant morphogenesis of Paris polyphylla var. Yunnanensis seeds, constructs the germ-free culture system, and lays the foundation for further studies on the growth, physiological and biochemical changes of Paris polyphylla var. Yunnanensis under germ-free condition.

Dormancy and germination characteristics of Nirtaria sibirica seeds / 中草药

Objective: To break the seed dormancy and improve the germination rate of the Nirtaria sibirica seeds. Methods: N. sibirica seeds were treated with soaking in warm water, storing with moisture sand, and immersing seed in H2SO4 (98%) and gibberellic acid (GA), then the germination rate, germination vigor, and germination peak period of the seeds were determined. Results: The germination rate and germination vigor were 30% and 10% under soaking in warm water. The seeds began to germinate on the day 7 and reached the germination peak on the day 10.The germination rate and germination vigor were 55.5% and 26.5% under storing with moisture sand for 37 d. The seeds began to germinate on the day 2 and reached the germination peak on the day 10.The germination rate and germination vigor were 86.8% and 60.3% under storing with moisture sand for 95 d. The seeds began to germinate on the day 2 and reached the germination peak on the day 7.The germination rate and germination vigor were both 90.0% under being treated with 98% H2SO4 for 2 h. The seeds began to germinate on the day 1 and reached the germination peak on the day 4.Seeds after being treated with 98% H2SO4 for 2 h were sowed on the dark medium of MS + 0.5 g/mL BA + 0.5 g/mL GA, and the germination rate and germination vigor both reached to 98.1%. The seeds began to germinate on the day 1 and reached the germination peak on the day 4. Conclusion: The dormancy of N. sibirica seeds is caused by hard seed vessels. The best way of breaking the seed dormancy is first treated with 98% H2SO4 for 2 h and then cultured in the dark medium of MS + 0.5 g/mL BA + 0.5 g/mL GA, which could effectively break the dormancy of hard seeds and reach a high germination rate.

Effects of different soaking treatments on seed germination and seedling growth of Platycodon grandiflorum / 中草药

Objective: To investigate the effects of different soaking treatments by KNO3, KMnO4, H2O2, GA3, and distilled water for different times on seed germination and seedling growth of Platycodon grandiflorum. Methods: Adopting a double-layer filter paper culture method, the seeds were cultured in the 12 h illumination light incubator at 25 °C, and the germination energy, germination percentage, germination index of the seeds, and the root length and the shoot height of the seedling were recorded. Then the data were analyzed. Results: The best soaking treatment to break seed dormancy, promote the seed germination, and improve the seedling growth of P. grandiflorum was with 0.150 g/L GA3 for 24 h. In addition, another effective soaking treatment is using 0.005 g/mL KNO3 for 12 h. Conclusion: The appropriate soaking reagent and time for the seed germination of P. grandiflorum are obtained, which could provide the guidance for seedling and artificial cultivating P. grandiflorum.

Germination of native grasses with potential application in the recovery of degraded areas in Quadrilátero Ferrífero, Brazil / Germinação de gramíneas nativas do Quadrilátero Ferrífero com potencial aplicação na recuperação de áreas degradadas

Native grasses are potential species to be used in land rehabilitation. However, due to the lack of better knowledge of their performance, preference is given to exotic plants, which may be invasive and negatively affect the local biodiversity. In order to better understand the propagation of native species of the Quadrilátero Ferrífero (Minas Gerais, Brazil) using their seeds, and in so doing, indicate possible candidates for land rehabilitation, this study investigated the germination patterns of the following grasses: Andropogon bicornis L.; Andropogon leucostachyus Kunth; Setaria parviflora (Poir.) Kerguélen; Cenchrus brownii Roem. & Schult; Echinolaena inflexa (Poir.) Chase, and Apochloa euprepes (Renvoize) Zuloaga & Morrone. The spikelets (depending on the species, removing or not the structures that surround the caryopsis) were treated as follows: T1-Control, T2-moistening with 0.2% potassium nitrate, T3-heating at 80 ºC for 2 minutes, T4-scarification with sulfuric acid (except genus Andropogon) and, for genera Andropogon and Setaria T5-storage at room temperature and T6- refrigerated storage. The treatment was repeated four times for 25 caryopses incubated at 25 ºC and constant light. Significant variation was observed when comparing germination rates from week to week, treatment to treatment and species to species. The most efficient treatment for genus Andropogon was T6, followed by T2 for A. bicornis and T3 for A. leucostachyus. T6 was also the most effective treatment for S. parviflora, followed by T5 and T2. C. brownii showed similar results when applying T1, T2 and T3 (mean 39%). E. inflexa and A. euprepes showed high levels of dormancy that were not overcome by the proposed treatments. A. bicornis, A. leucostachyus, S. parviflora and C. brownii showed higher germination potential, thus being possible candidates for the recovery of degraded areas. Future studies are indicated to find the most effective treatments for germination in field conditions.

As gramíneas nativas apresentam potencial para revegetação de áreas degradadas, no entanto, devido ao pouco conhecimento sobre sua biologia, dá-se preferência ao uso de espécies exóticas, que podem ser invasoras, afetando assim a biodiversidade local. No intuito de ampliar o conhecimento acerca da propagação via sementes de espécies nativas do Quadrilátero Ferrífero (QF), e desta forma, indicar possíveis candidatas a aplicação na recuperação de áreas degradadas da região, este trabalho objetivou avaliar os padrões germinativos das seguintes gramíneas: Andropogon bicornis L.; Andropogon leucostachyus Kunth; Setaria parviflora (Poir.) Kerguélen, Cenchrus brownii Roem. & Schult; Echinolaena inflexa (Poir.). Chase e Apochloa euprepes (Renvoize) Zuloaga & Morrone. As espiguetas (com presença ou não das estruturas que envolviam a cariopse, dependendo da espécie) foram submetidas aos seguintes tratamentos: T1-controle; T2-umedecimento do substrato com 0,2% de nitrato de potássio, T3-aquecimento a 80 ºC por 2 minutos, T4-escarificação com ácido sulfúrico (exceto gênero Andropogon) e para os gêneros Andropogon e Setaria, T5-armazenamento a temperatura ambiente e T6-armazenamento sob refrigeração. Os tratamentos foram realizados em 4 repetições de 25 cariopses colocadas para germinar a temperatura de 25 ºC e iluminação constante. Variação significativa foi observada quando comparadas as quantidades de germinações ocorridas entre as semanas, entre os tratamentos e entre as espécies. Para o gênero Andropogon o tratamento mais eficiente foi T6, seguido por T2 em A. bicornis e T3 em A. leucostachyus. T6 também foi o tratamento mais eficiente para S. parviflora, seguido por T5 e T2. C. brownii apresentou resultados próximos sob T1, T2 e T3 (média 39%). E. inflexa e A. euprepes apresentaram altos índices de dormência que não foram superadas pelos tratamentos propostos. A. bicornis, A. leucostachyus, S. parviflora e C. brownii apresentaram maiores potenciais de germinação, sendo possíveis candidatas para recuperação de áreas degradas no QF. No entanto, ainda são necessários estudos complementares com os tratamentos mais eficientes e testes de germinação e estabelecimento em condições de campo.

Seed germination and seedling vigour of italian ryegrass, cocksfoot and timothy following harvest and storage / Germinação de sementes e o vigor de plantas jovens de azevem italiano, dactilis e timóteo após a colheita e o armazenamento

During post-harvest maturation, different species vary in the length of dormancy breaking or germination increases. Seed dormancy and slow seedling development often limit establishment of forage grass stands. Seed germination and seedling vigour of Italian ryegrass (Lolium italicum A. Braun, Synonym Lolium multiflorum L.), cocksfoot (Dactylis glomerata L.) and timothy (Phleum pretense L.) were observed after harvest and storage. After harvest in June, seeds were stored under standard storage conditions and sampled every 30 days after harvest (DAH), up to 270 DAH, and then every 60 days up to 990 DAH. At each date, seeds were tested for final germination percentage and for seedling vigour traits. Timothy seeds had a maximum germination (88 percent) and the best seedlings vigour at 90 DAH, which implies that early autumn (September-October) is the best sowing period for freshly harvested seeds of timothy. Timothy seed germination was poor from 270 DAH (73 percent). The best germination and vigour of Italian ryegrass and cocksfoot seedlings were between 270 and 330 DAH, which equates to spring sowing time (March-April) in the succeeding year. Cocksfoot and Italian ryegrass seeds maintained satisfactory germination levels up to 630 DAH (81 percent) and 810 DAH (81 percent), respectively. The data can serve for the determination of a proper storage duration management between harvest and sowing of the tested species under ambient conditions of south-eastern Europe.

Durante o armazenamento, diferentes espécies comportam-se diferentemente quanto à dormência e crescimento de plântulas. A dormência o desenvolvimento lento das plântulas limitam a época do plantio das gramíneas forrageiras plurianuais. A germinação de sementes e o crescimento das plântulas de azevem italiano (Lolium italicum A. Braun sin. Lolium multiflorum L.), Dactilis (Dactilis glomerata L.) e de timoteo (Phleum pratense L.) foi pesquisada durante a maturação pós-colheita e a silagem. Após a colheita, em junho, sementes foram armazenadas em condições tradicionais e analisadas a cada 30 dias após a colheita, até 270 dias e, em seguida, a cada 60 dias até 990 dias. Nessa pesquisa, avaliou-se a germinação final e o vigor das plântulas. As sementes de timoteo obtiveram germinação máxima (88 por cento) e o melhor crescimento das plântulas após 90 dias de armazenamento, indicando que o melhor período para o plantio das sementes colhidas em junho é o inicio de outono (setembro-outubro). A germinação de sementes de timoteo reduziu nos 270 dias (73 por cento) seguintes. A melhor germinação, e crescimento da plântula do azevem italiano e do dactilis ocorreu entre 270 e 330 dias, indicando que a melhor época para plantio é na primavera (março-abril), do ano seguinte. As sementes de dactilis e azevem italiano mantiveram germinação satisfatória até 630 dias (81 por cento) e 810 dias (81 por cento), respectivamente. Essa pesquisa pode servir para determinação de gerenciamento adequado de duração de armazenamento entre a colheita e o plantio das espécies testadas em condições de armazenamento no sudeste da Europa.

Germination and soil seed bank traits of Podocarpus angustifolius (Podocarpaceae): an endemic tree species from Cuban rain forests

Podocarpus angustifolius is an endangered recalcitrant-seeded small tree, endemic to mountain rain forests in the central and Pinar del Río regions in Cuba. In this study, the germination patterns of P. angustifolius seeds were evaluated and the nature of the soil seed bank was determined. Using a weighted two-factor design, we analyzed the combined germination response to seed source (i.e. freshly matured seeds directly collected from trees versus seeds extracted from soil samples) and pretreatment (i.e. seed water-immersion for 48h at room temperature). Germination was delayed for four weeks (≈30 days) in all cases, regardless of both factors analyzed. Moreover, nine additional days were necessary to achieve high germination values (in the case of fresh, pretreated seeds). These results overall may indicate the existence of a non-deep simple morphophysiological dormancy in P. angustifolius seeds. The water-immersion significantly enhanced seed germination, probably as a result of the hydration of recalcitrant seeds. Although germination of seeds extracted from soil samples was low, probably due to aging and pathogen effects throughout the time of burial, the study revealed the existence of a persistent soil seed bank (at least short-termed) of ≈42 viable seeds per m² in the upper 10cm of soil. Such a record is noteworthy since references to persistent soil seed banks in recalcitrant-seeded species are scarce in the literature. The population consequences derived from the formation of persistent soil seed banks in this endangered species are discussed. Rev. Biol. Trop. 59 (3): 1061-1069. Epub 2011 September 01.

Podocarpus angustifolius es un árbol endémico de los bosques lluviosos de la región de Pinar del Río y la parte central de Cuba, que se encuentra en peligro de extinción. En este estudio se evaluó la germinación de sus semillas y la naturaleza del banco de semillas del suelo. Específicamente, se analizó la respuesta germinativa de las semillas a dos factores: su procedencia (recolectadas directamente de los árboles versus extraídas de muestras de suelo) y el pretratamiento (inmersión en agua durante 48h a temperatura ambiente). La germinación no comenzó hasta las cuatro semanas (≈30 días) en todos los casos. Además, fueron necesarios 9 días más para alcanzar un valor elevado de germinación (en el caso de semillas recolectadas del árbol con pretratamiento), lo que parece indicar la existencia de un letargo de tipo morfofisiológico simple no profundo. El pretratamiento incrementó significativamente la germinación, posiblemente por hidratación de las semillas recalcitrantes. El estudio demostró la existencia de un banco de semillas persistente en el suelo, al menos de corta duración de ≈42 semillas viables por m² en los 10 primeros cm del suelo. Dicho hallazgo es destacable, ya que los casos descritos en la literatura sobre bancos persistentes en especies con semillas recalcitrantes son escasos. Además, se discute la importancia que tiene para esta especie amenazada la existencia de un banco de semillas persistente.

Dormancy break in seeds of quina (Strychnos pseudoquina A. St.-Hil.) / Superação da dormência de sementes de quina (Strychnos pseudoquina A. St.-Hil.)

"Quina" (Strychnos pseudoquina A. St. Hil) is a medicinal plant species from the Brazilian Cerrado. As its seeds show dormancy, they were subjected to the treatments pre-cooling at 5ºC during 7 days, pre-heating at 40ºC during 7 days, pre-soaking in sulfuric acid PA during 5 and 15 min, pre-soaking in boiling water during 5 and 15 min, pre-soaking in 100 and 200 ppm gibberellic acid during 48 h, pre-soaking in distilled water during 24 and 48 h, and mechanical scarification to break dormancy. Counts were daily conducted from the 2nd day after the experiment implementation until the germination stabilization at the 65th day. The germination speed index (GSI) and the germination percentage were evaluated. Germination rates above 96 percent were reached in seeds pre-soaked in water during 48 h and substrate moistened with water or KNO3.

A quina (Strychnos pseudoquina A. St.-Hil) é espécie medicinal do Cerrado Brasileiro. As sementes apresentam dormência e, por isso, foram submetidas aos tratamentos pré-resfriamento a 5ºC durante 7 dias, pré-aquecimento a 40ºC durante 7 dias, pré-embebição em ácido sulfúrico P.A. durante 5 e 15 minutos, pré-embebição em água fervente durante 5 e 15 minutos, pré-embebição em ácido giberélico a 100 e 200 ppm, durante 48 horas, pré-embebição em água destilada durante 24 e 48 horas e escarificação mecânica, visando à superação da dormência. Foram realizadas contagens diárias entre o 2º dia após a implantação do experimento até a estabilização da germinação, que ocorreu no 65º dia. Foram avaliados o índice de velocidade de germinação (IVG) e a porcentagem de germinação. Taxas de germinação acima de 96 por cento foram atingidas em sementes pré-embebidas em água durante 48 horas e substrato umedecido com água ou KNO3.