Vale Ellen Moura, Reis Ricardo Souza, Passamani Lucas Zanchetta, Santa-Catarina Claudete, Silveira Vanildo
1Laboratório de Biotecnologia, Centro de Biociências e Biotecnologia (CBB), Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Av. Alberto Lamego 2000, Campos dos Goytacazes, RJ 28013-602 Brazil.
2Unidade de Biologia Integrativa, Setor de Genômica e Proteômica, UENF, Av. Alberto Lamego 2000, Campos dos Goytacazes, RJ 28013-602 Brazil.
Physiol Mol Biol Plants. 2018 Mar;24(2):295-305. doi: 10.1007/s12298-017-0501-4. Epub 2018 Jan 18.
Efficient protocols for somatic embryogenesis of papaya ( L.) have great potential for selecting elite hybrid genotypes. Addition of polyethylene glycol (PEG), a nonplasmolyzing osmotic agent, to a maturation medium increases the production of somatic embryos in . . To study the effects of PEG on somatic embryogenesis of . , we analyzed somatic embryo development and carbohydrate profile changes during maturation treatments with PEG (6%) or without PEG (control). PEG treatment (6%) increased the number of normal mature somatic embryos followed by somatic plantlet production. In both control and PEG treatments, pro-embryogenic differentiation to the cotyledonary stage was observed and was significantly higher with PEG treatment. Histomorphological analysis of embryonic cultures with PEG revealed meristematic centers containing small isodiametric cells with dense cytoplasm and evident nuclei. Concomitant with the increase in the differentiation of somatic embryos in PEG cultures, there was an increase in the endogenous content of sucrose and starch, which appears to be related to a rising demand for energy, a key point in the conversion of . somatic embryos. The endogenous carbohydrate profile may be a valuable parameter for developing optimized protocols for the maturation of somatic embryos in papaya.
高效的番木瓜体细胞胚胎发生方案在选择优良杂交基因型方面具有巨大潜力。向成熟培养基中添加聚乙二醇（PEG）这种非质壁分离渗透剂，可增加体细胞胚胎的产量。为了研究PEG对番木瓜体细胞胚胎发生的影响，我们分析了在添加PEG（6%）或不添加PEG（对照）的成熟处理过程中体细胞胚胎的发育和碳水化合物谱的变化。PEG处理（6%）增加了正常成熟体细胞胚胎的数量，随后产生了体细胞幼苗。在对照和PEG处理中，均观察到了从原胚性分化到子叶期的过程，且PEG处理的分化率显著更高。对含PEG的胚胎培养物进行组织形态学分析发现，分生中心含有小的等径细胞，细胞质致密，细胞核明显。随着PEG培养物中体细胞胚胎分化的增加，蔗糖和淀粉的内源含量也增加，这似乎与能量需求的增加有关，而能量需求增加是番木瓜体细胞胚胎转化的关键因素。内源碳水化合物谱可能是制定番木瓜体细胞胚胎成熟优化方案的一个有价值的参数。
