RESUMO -a determinação do nível de ploidia é muito importante, principalmente em programas de melhoramento genético que envolvem poliploides, a fim de possibilitar a escolha adequada dos materiais vegetais com os quais se deseja trabalhar. a relação entre o conteúdo de Dna de acessos de bananeira e sua ploidia ainda permanece controversa na literatura; assim, o presente trabalho teve como objetivo avaliar o conteúdo de Dna de acessos de bananeira com diferentes níveis de ploidia. Foram avaliados sete acessos tetraploides, quatro triploides e quatro diploides. a determinação do conteúdo foi realizada pela técnica de citometria de fluxo. Foram trituradas entre 50-60 mg de folhas frescas, juntamente com o padrão interno (Pisum sativum) no tampão LB01, e, posteriormente, as amostras foram filtradas em gaze e filtro de 50 µm. Adicionaram-se 5 µL de RNase e 25 µL de iodeto de propídeo. Para cada amostra, foram analisados 10 mil núcleos, com três repetições. os resultados obtidos para o conteúdo de Dna permitiram estimar o tamanho dos genomas a e B, sendo o primeiro cerca de 14% maior que o segundo. os resultados apresentaram clara relação entre o conteúdo de Dna e o nível de ploidia dos materiais. o contéudo de Dna apresentou aumento médio de 30% nas cultivares diploides em relação às cultivares triploides avaliadas e de 25% nas cultivares triploides em relação às cultivares tetraploides. apesar da diferença nos tamanhos dos genomas a e B, contribuições distintas desses dois genomas não foram diretamente relacionadas com alterações no conteúdo do Dna de cultivares tetraploides. Termos para indexção: Musa sp. Conteúdo de DNA. Ploidia. Citometria de fluxo. ESTIMATE OF DNA CONTENT OF DIFFERENT ACCESS OF BANANA: RELATIONS BETWEEN PLOID LEVEL AND GENOME GROUPSABSTRACT -Ploidy determination is very important, especially in breeding programs, to allow the correct choice of plant material to work. the relation between Dna content and ploidy level still has some controversies in literature, so the present study had the aim of evaluate Dna content in banana accesses with different ploidy levels. Data were evaluated from six tetraploid, four triploids and four diploids accesses. 50-60 mg of leave material were crushed with material from internal standard (Pisum sativum) in lB01 buffer and then filtered through gauze and 50 µm filter. It was added 5 µL of RNase and 25 µL of propide iodate. For each sample 10 thousand nuclei were analyzed with three repetitions. the Dna content results allowed separating genome a and B. Genome a appeared to be 14% major than genome B. Results showed a clear relationship between Dna content and ploidy level. Dna content increased 30% on average from diploid to triploid cultivars and 25% from triploid cultivars to tetraploid cultivars. Despite the size difference between genome a and B it could not be found a direct relationship between the contribution of these two genomes and the size of Dna content in tetraploid cultivars.
Many important crops have cultivars with different ploidy and provide a diverse choice of materials for breeding programs. Therefore, it is essential to accurately assess the ploidy of all breeding materials. Increased DNA content is known to have various effects on external and internal morphology, an effect known as the “nucleotypic effect”. Thus, anatomical assessment can be used as a tool for determining ploidy in plants, making the chromosome counting technique or flow cytometry unnecessary. This study aimed to evaluate the leaf anatomical characteristics of banana cultivars and understand the relationship between these features and ploidy levels. Thirteen accessions were evaluated, including diploid, triploid, and tetraploid genotypes, and cultivars, resulting from in vitro propagation after 90 days of acclimatization. Five fully expanded young leaves were collected from each cultivar, fixed in FAA70 (formaldehyde–acetic acid–ethanol) and preserved in 70% alcohol. Transverse and paradermal sections of the abaxial and adaxial regions were taken, and variables such as size and stomatal density, leaf thickness in the midrib and fourth vascular bundle region, and thickness of the epidermis, hypodermis, and parenchyma were measured. Results for leaf thickness, stomatal size, and density proved to be appropriate parameters for characterizing banana ploidy levels.
Conditions of water deficit can cause morphological changes in plants which consequently affect physiological processes and interfere with plant metabolism. As grafting is a standard process used for citrus trees, these changes depend on the rootstock used and its interaction with the scion; this interaction will determine which plant has the best performance. This study involved assessment of changes in DNA and chlorophyll A and B content in Navelate orange seedlings grafted onto five different rootstocks (Indian and San Diego citrandarin, Swingle citrumelo, Santa Cruz Rangpur lime and Sunki mandarin) under conditions of water deficit. The seedlings from the respective combinations were approximately 12 months-old when they were transferred to 5 L polyethylene bags filled with substrate, comprising standard soil and sand at a 3:1 ratio. Plants were maintained in a greenhouse for three months. After this period, the experiment was set up using a randomized block design with a 5x2x5 factorial scheme based on the following: five rootstocks with and without irrigation, and time-points at 25, 29, 32, 35 and 38 d after stopping irrigation. At each of these time-points, chlorophyll content was assessed by direct reading in cloroLOG CFL1030 equipment and also the DNA content was determined using flow cytometry. The results suggest that severe water deficit can cause morphological changes in DNA content and in chlorophyll concentration, and that the changes are most marked with Sand Diego and Swingle rootstocks. Index terms: flow cytometry, chlorophyll content. Respostas morfológicas da laranjeira Navelate enxertada em diferentes porta-enxertos e sob déficit hídrico RESUMOAs condições de déficit hídrico podem causar alterações morfológicas em plantas que consequentemente afetam os processos fisiológicos e interferem em seu metabolismo. Essas mudanças dependem do porta-enxerto usado e sua relação com a copa uma vez que a enxertia é um processo padrão usado na formação das plantas cítricas. Este estudo teve como objetivo identificar o melhor desempenho da interação de diferentes porta-enxertos com a copa Navelate em condições de estresse hídrico; mediante avaliação do conteúdo de DNA e clorofila A e B. Foram estudados os portaenxertos citrandarin Indio e San Diego, citrumelo Swingle, limão Cravo Santa Cruz e tangerina Sunki
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