Efeito de temperaturas e substratos na germinação de sementes de Myracrodruon urundeuva Fr. All. (Anacardiaceae)

Abstract

Myracrodruon urundeuva Fr. All. (Anacardiaceae) é uma espécie arbórea nativa que apresenta excelentes propriedades físicas, químicas e biológicas. Entretanto, devido à exploração predatória, está na lista oficial das espécies brasileiras ameaçadas de extinção. Este trabalho teve como objetivo estudar a germinação das sementes de M. urundeuva sob diferentes substratos e regimes de temperatura. O delineamento experimental adotado foi o inteiramente casualizado, em arranjo fatorial 8 x 7 (oito substratos - entre e sobre: papel mata-borrão, areia, vermiculita e pó de coco; sete temperaturas: 25, 27, 30, 35, 20-27, 20-30 e 20-35 ºC), com quatro repetições de 25 sementes cada. Avaliaram-se as seguintes características: germinação (%), primeira contagem (%), índice de velocidade de germinação, tempo médio de germinação (dias) e comprimento (cm) do hipocótilo e da raiz primária. Nas temperaturas constantes ocorreram os tempos médios menores de germinação de sementes e desenvolvimento maior do hipocótilo. As temperaturas de 25 e 27 ºC proporcionaram às sementes resultados satisfatórios de germinação em todos os substratos testados, com exceção do substrato entre papel a 27 ºC. Os substratos vermiculita e pó de coco permitiram bom desempenho germinativo e não exigiram reumedecimento diário, mostrando-se adequados para a avaliação da qualidade fisiológica de sementes de M. urundeuva.

<b>Chronological analysis of the physiological quality of diaspores of <i>Myracrodruon urundeuva</i> Fr. All. in semiarid regions

“…The germination rate of the collected M. urundeuva diaspores varied between 4% and 93%. A similarly large variation (between 16% and 90%) was also reported by (Dorneles, Ranal, & Santana, 2005;Pacheco et al, 2006;Nunes, Fagundes, Almeida, & Veloso, 2008;Guedes et al, 2011;Virgens et al, 2012;Scalon, Scalon Filho, & Masetto, 2012).…”

<b>Chronological analysis of the physiological quality of diaspores of <i>Myracrodruon urundeuva</i> Fr. All. in semiarid regions

“…The germination rate of the collected M. urundeuva diaspores varied between 4% and 93%. A similarly large variation (between 16% and 90%) was also reported by (Dorneles, Ranal, & Santana, 2005;Pacheco et al, 2006;Nunes, Fagundes, Almeida, & Veloso, 2008;Guedes et al, 2011;Virgens et al, 2012;Scalon, Scalon Filho, & Masetto, 2012).…”

TEMPERATURE AND SUBSTRATE INFLUENCES ON SEED GERMINATION AND SEEDLING FORMATION IN Callisthene fasciculata Mart. (VOCHYSIACEAE) IN THE LABORATORY1

“…and reported that a temperature of 25 °C was more suitable for germination and vigor tests on seeds, regardless of substrate. A similar result was observed by Pacheco et al (2006) with the seeds of Myracrodruon urundeuva Allemão, where temperatures of 25 and 27 °C resulted in satisfactory seed germination on all substrates except for paper.…”

Germination and vigor of Dimorphandra mollis benth. seeds under different temperatures and substrates

“…mollis seeds also germinated at high percentages in the sand substrate but, as was reported by Pacheco et al (2006) with seeds from Myracrodruon urundeuva Fr. All., it is sometimes difficult to maintain high humidity levels in this substrate (which may have contributed to the lack of uniformity observed in the length of the aerial part of the seedlings, as seen in Figure 1).…”

<b>Chronological analysis of the physiological quality of diaspores of <i>Myracrodruon urundeuva</i> Fr. All. in semiarid regions

“…The germination rate of the collected M. urundeuva diaspores varied between 4% and 93%. A similarly large variation (between 16% and 90%) was also reported by (Dorneles, Ranal, & Santana, 2005;Pacheco et al, 2006;Nunes, Fagundes, Almeida, & Veloso, 2008;Guedes et al, 2011;Virgens et al, 2012;Scalon, Scalon Filho, & Masetto, 2012).…”

TEMPERATURE AND SUBSTRATE INFLUENCES ON SEED GERMINATION AND SEEDLING FORMATION IN Callisthene fasciculata Mart. (VOCHYSIACEAE) IN THE LABORATORY1

“…and reported that a temperature of 25 °C was more suitable for germination and vigor tests on seeds, regardless of substrate. A similar result was observed by Pacheco et al (2006) with the seeds of Myracrodruon urundeuva Allemão, where temperatures of 25 and 27 °C resulted in satisfactory seed germination on all substrates except for paper.…”

Germination and vigor of Dimorphandra mollis benth. seeds under different temperatures and substrates

“…mollis seeds also germinated at high percentages in the sand substrate but, as was reported by Pacheco et al (2006) with seeds from Myracrodruon urundeuva Fr. All., it is sometimes difficult to maintain high humidity levels in this substrate (which may have contributed to the lack of uniformity observed in the length of the aerial part of the seedlings, as seen in Figure 1).…”

<b>Chronological analysis of the physiological quality of diaspores of <i>Myracrodruon urundeuva</i> Fr. All. in semiarid regions

“…The germination rate of the collected M. urundeuva diaspores varied between 4% and 93%. A similarly large variation (between 16% and 90%) was also reported by (Dorneles, Ranal, & Santana, 2005;Pacheco et al, 2006;Nunes, Fagundes, Almeida, & Veloso, 2008;Guedes et al, 2011;Virgens et al, 2012;Scalon, Scalon Filho, & Masetto, 2012).…”

TEMPERATURE AND SUBSTRATE INFLUENCES ON SEED GERMINATION AND SEEDLING FORMATION IN Callisthene fasciculata Mart. (VOCHYSIACEAE) IN THE LABORATORY1

“…and reported that a temperature of 25 °C was more suitable for germination and vigor tests on seeds, regardless of substrate. A similar result was observed by Pacheco et al (2006) with the seeds of Myracrodruon urundeuva Allemão, where temperatures of 25 and 27 °C resulted in satisfactory seed germination on all substrates except for paper.…”

Germination and vigor of Dimorphandra mollis benth. seeds under different temperatures and substrates

“…mollis seeds also germinated at high percentages in the sand substrate but, as was reported by Pacheco et al (2006) with seeds from Myracrodruon urundeuva Fr. All., it is sometimes difficult to maintain high humidity levels in this substrate (which may have contributed to the lack of uniformity observed in the length of the aerial part of the seedlings, as seen in Figure 1).…”