Abstract:RESUMO -O biribazeiro (Rollinia mucosa [Jacq.]) é uma frutífera nativa da América Central e América do Sul que se destaca das demais espécies do gênero por apresentar frutos grandes e comestíveis. Tendo em vista que pouco se conhece a respeito da anatomia da planta, tipo de reserva da semente, como também sobre o conteúdo de DNA de espécies da família anonáceas, este trabalho teve por objetivos caracterizar histoquimicamente as sementes e anatomicamente as plântulas, e determinar o conteúdo de DNA de biribazei… Show more
“…This was also observed in seeds of Acrocomia aculeata (Ribeiro et al, 2010). However, no difficulties were found in this study for the analysis of results, although atemoya seeds had predominantly lipid reserves, in the same manner as other species of the family Annonaceae, such as A. muricata (Kimbonguila et al, 2010), A. squamosa (Masruri et al, 2012) and Rollinia mucosa (Soares et al, 2014). Because of factors relative to the standardization of the method, different results are obtained between genera of the same family and even between species of the same genus.…”
-The study aimed to adapt the tetrazolium test to assess the viability of atemoya (Annona cherimola Mill. x A. squamosa L.) seeds. The experimental design was completely randomized in 3 x 3 factorial arrangement (tetrazolium salt concentrations x exposure times), totaling 9 treatments with four replicates of 25 seeds. After immersion in water for 24 hours, the seeds were longitudinally sectioned and exposed to three tetrazolium salt concentrations (0.05%, 0.5% and 1%) for three periods of time (2, 4 and 6 hours). The evaluations were performed according to pre-established criteria of tissue integrity and staining. The germination test was performed, using the GA 4+7 + N-(fenilmetil)-aminopurina regulators at concentrations of 0 and 300 mg.L -1 , because dormancy is observed in species of the family Annonaceae. Tetrazolium salt at 1% yielded the highest percentage of viable seeds within the shortest time, while longer exposure times were necessary with concentrations of 0.05% and 0.5%. It can be concluded that the concentration of 1% of tetrazolium salt for two hours of exposure is more appropriate for assessing the viability of atemoya seeds.
“…This was also observed in seeds of Acrocomia aculeata (Ribeiro et al, 2010). However, no difficulties were found in this study for the analysis of results, although atemoya seeds had predominantly lipid reserves, in the same manner as other species of the family Annonaceae, such as A. muricata (Kimbonguila et al, 2010), A. squamosa (Masruri et al, 2012) and Rollinia mucosa (Soares et al, 2014). Because of factors relative to the standardization of the method, different results are obtained between genera of the same family and even between species of the same genus.…”
-The study aimed to adapt the tetrazolium test to assess the viability of atemoya (Annona cherimola Mill. x A. squamosa L.) seeds. The experimental design was completely randomized in 3 x 3 factorial arrangement (tetrazolium salt concentrations x exposure times), totaling 9 treatments with four replicates of 25 seeds. After immersion in water for 24 hours, the seeds were longitudinally sectioned and exposed to three tetrazolium salt concentrations (0.05%, 0.5% and 1%) for three periods of time (2, 4 and 6 hours). The evaluations were performed according to pre-established criteria of tissue integrity and staining. The germination test was performed, using the GA 4+7 + N-(fenilmetil)-aminopurina regulators at concentrations of 0 and 300 mg.L -1 , because dormancy is observed in species of the family Annonaceae. Tetrazolium salt at 1% yielded the highest percentage of viable seeds within the shortest time, while longer exposure times were necessary with concentrations of 0.05% and 0.5%. It can be concluded that the concentration of 1% of tetrazolium salt for two hours of exposure is more appropriate for assessing the viability of atemoya seeds.
“…The genome size reported here is similar to Lorenzoni (2016) : 2C = 5.42 pg (±0.12) with 15 accessions of unknown origin of hexaploid cultivated plants maintained at the Federal University of Espírito Santo (Alegre, ES, Brazil). The other two studies showed divergences in the size of the A. mucosa genome ( Soares et al, 2014 ; Leitch et al, 2019 ), but methods, sample sizes and provenances are unclear.…”
Section: Discussionmentioning
confidence: 99%
“…Annona mucosa has two ploidy levels: 2 n = 4x = 28 in a population in Peru ( Maas et al, 1992 ) and 2 n = 6x = 42 in domesticated populations in Brazil ( Morawetz, 1986b ; Lorenzoni, 2016 ). The species also appears to present genome size variation (2C = 4.77, 5.42 and 6.00 pg) ( Soares et al, 2014 ; Lorenzoni, 2016 ; Leitch et al, 2019 ). However, the cytogenetic and genome size studies of A. mucosa have many gaps, such as the absence of exact collection location and the lack of information about the phenotype of the fruits in the published studies.…”
Background
Biribá (Annona mucosa Jacq.) is a fruit tree domesticated in Amazonia and has polyploid populations. The species presents ample phenotypic variation in fruit characteristics, including weight (100–4,000 g) and differences in carpel protrusions. Two cytotypes are recorded in the literature (2n = 28, 42) and genome size records are divergent (2C = 4.77, 5.42 and 6.00 pg). To decipher the role of polyploidy in the domestication of A. mucosa, we examined the relationships among phenotypic variation, chromosome number and genome size, and which came first, polyploidization or domestication.
Methodology
We performed chromosome counts of A. mucosa from central and western Brazilian Amazonia, and estimated genome size by flow cytometry. We performed phylogenetic reconstruction with publicly available data using a Bayesian framework, time divergence analysis and reconstructed the ancestral chromosome number for the genus Annona and for A. mucosa.
Results
We observed that variation in fruit phenotypes is not associated with variation in chromosome number and genome size. The most recent common ancestor of A. mucosa is inferred to be polyploid and diverged before domestication.
Conclusions
We conclude that, when domesticated, A. mucosa was already polyploid and we suggest that human selection is the main evolutionary force behind fruit size and fruit morphological variation in Annona mucosa.
“…Annona mucosa has two ploidy levels: 2n = 4x = 28 in probably wild populations in Peru (Maas & al., 1992) and 2n = 6x = 42 in domesticated populations in Brazil (Morawetz, 1986;Lorenzoni, 2016). The species also appears to be variable in genome size (2C = 4.77, 5.42 and 6.00 pg) (Soares & al., 2014;Lorenzoni, 2016;Leitch & al., 2019). Recent studies identified wild populations of A. mucosa in Mexico (Segura & al., 2018;Escobedo-López & al., 2019).…”
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