-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.
Atemoya currently has its seeds studied in several aspects, from the technological and physiological point of view. However, for the performance of the germination test, there is no standardization in relation to the number of seeds and replicates. Thus, this work aims to determine the optimal sample size for germination tests with atemoya seeds. A germination test was carried out with 5 treatments, considering 10, 20, 30 40 and 50 seeds per sampling unit with 50 replicates of each. Data were analyzed using logistic regression, non-linear Gompertz regression models, bootstrap simulation and graphs in the form of contour lines in order to be able to infer the best binomial of the number of seeds per sampling unit and the number of replicates. The expected germination percentage, maximum germination speed and times for the beginning of the germination process, maximum germination speed and interruption of the germination process were determined. The treatment of 20 seeds per sampling unit statistically differs from that of 40 seeds by the Tukey-Kramer test with 5% significance. It could be concluded that for germination tests with atemoya seeds to have statistical validity, the smallest sample size is 10 seeds per unit, regardless of number of replicates.
-The objective of this study was to evaluate the effect of different water contents achieved by Annona emarginata (Schltdl.) H. Rainer seeds during immersion in GA 3 solutions, in variation of soluble sugars levels and germination. Seeds with 10% of initial water content were submitted to imbibition in GA 3 solutions with concentrations of 0; 250; 500; 750 and 1000 mg L -1 and when they reached the water content of 15%, 20%, 25%, 30% and 35%, the quantification of soluble sugars levels and germination test were performed. Seeds immersed up to they reach 15% of water with GA 3 and immersed up to the water acquisition of 20% without GA 3 , presented higher soluble sugars levels and germination percentage, which were decreased when the seeds reached 30% and 35% of water, independently of the presence of the plant growth regulator. It was conclude that different water contents reached by the seeds in immersion treatments with GA 3 affect the soluble sugars levels and germination percentage of Annona emarginata seeds. Thus, in treatments with Annona emarginata, the seeds must remain immersed in water without GA 3 up to they reach 20% of water, as higher water contents (35%) reduce the soluble sugars levels and the seed germination percentage. Index terms: Annonaceae, "araticum-de-terra-fria", carbohydrates, imbibition. AÇÚCARES SOLÚVEIS E GERMINAÇÃO DE SEMENTES DE Annona emarginata (Schltdl.) H. Rainer SUBMETIDAS À IMERSÃO EM GA 3 ATÉ DIFERENTES TEORES DE ÁGUARESUMO -O objetivo deste trabalho foi avaliar o efeito de diferentes teores de água atingidos pelas sementes de Annona emarginata (Schltdl.) H. Rainer durante a imersão em soluções de GA 3 , na variação dos teores de açúcares solúveis e na germinação. Sementes com teor de água inicial de 10% foram colocadas para embeber em soluções com as concentrações de 0; 250; 500; 750 e 1.000 mg L -1 de GA 3, e ao atingirem os teores de 15%, 20%, 25%, 30% e 35% de água, procedeu-se à quantificação dos teores de açúcares solúveis e ao teste de germinação. As sementes imersas até atingirem 15% de água com a adição de GA 3 e imersas até a aquisição de 20% de água sem a adição de GA 3 apresentaram maiores teores de açúcares solúveis e porcentagens de germinação, os quais foram reduzidos à medida que as sementes atingiram 30% e 35% de água, independentemente do uso do regulador vegetal. Conclui-se que os diferentes teores de água alcançados pelas sementes nos tratamentos de imersão afetam os teores de açúcares solúveis e a germinação de sementes de Annona emarginata. Assim, em tratamentos com Annona emarginata, as sementes devem permancer imersas na água sem a adição de GA 3 até a aquisição de 20% de água, uma vez que elevados teores de água (35%) reduzem os teores de açúcares solúveis totais e a porcentagem de germinação das sementes. Termos para indexação: Annonaceae, "araticum-de-terra-fria", carboidratos, embebição.
Grafting is an effective technique used in the cultivation of commercial fruit species given the necessity to guarantee the genetic characteristics of productive species using selected clones. Although grafting is a common and widespread technique and phytohormones play a key role in the formation of tissues, the relationship between phytohormones, such as abscisic acid, and mechanisms of incompatibility is not yet well elucidated. Thus, the objective of this study was to establish whether a correlation exists between variations in abscisic acid and the compatibility of the atemoya (Annona x atemoya Mabb.) cultivar ‘Thompson’ grafted onto biribá [Annona mucosa (Bail.) H. Rainer], araticum-mirim [Annona emarginata (Schltdl.) H. Rainer ‘var. mirim’] and araticum-de-terra-fria [Annona emarginata (Schltdl.) H. Rainer ‘var. terra-fria’]. Plant cultivation was carried out at the Botany Department of Instituto de Biociências (IB), Unesp, Botucatu, São Paulo, Brazil. The plant material of grafted plants (stem above the grafted area, stem containing the grafted region, and stem below the grafted region) and ungrafted plants (stem 20 cm above ground) was collected 500 days after grafting (DAG) for the extraction and quantification of abscisic acid. The results of this study show that ungrafted Annona plants exhibit variations in the concentration of abscisic acid among the native rootstock species. When grafted, the most commonly used grafting combinations, araticum-de-terra-fria and araticum-mirim, present the same concentrations of abscisic acid in the graft region as self-grafted atemoya. It was concluded that the observed variations in the concentrations of abscisic acid in the graft region did not cause incompatibility in the combinations of atemoya grafted onto different native species.
Germination pattern may be affected when seeds are dispersed under flooded conditions or subjected to pre-germination treatments such as immersion in plant growth regulators and priming. We evaluated the metabolic and ultrastructural changes in the seeds of Annona emarginata (Schltdl.) H. Rainer seeds caused by immersion in water (0 MPa) during the imbibition phase (phase I). The immersion time necessary for initially dry seeds (10% water content) to reach a water content of 15%, 20%, and 35% was recorded. The seeds were also immersed in a polyethylene glycol 6000 solution (–1.2 MPa) to decrease the rate of water uptake and increase the immersion times required for the seeds to reach the selected water contents. With shorter immersion times, seed damage did not decrease germinability. Seeds immersed for 122 h sustained damage to the cell membrane system and organelles, resulting in a decreased percentage and rate of germination. Decreasing the rate of water uptake increased the time required to finish imbibition phase to 317 h and resulted in more ultrastructural damages and a decreased germination index. We conclude that in seeds with slower imbibition, longer immersion times may cause severe metabolic damage if the seeds are immersed until the end of the imbibition phase, resulting in reduced germination.
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