Key message

Cytokinin might be an important factor to regulate floral sex at the very early stage of flower development in sacha inchi.

Abstract

Sacha inchi (Plukenetia volubilis, Euphorbiaceae) is characterized by having female and male flowers in a thyrse with particular differences. The mechanisms involved in the development of unisexual flowers are very poorly understood. In this study, the inflorescence and flower development of P. volubilis were investigated using light microscopy and scanning electron microscopy. We also investigated the effects of cytokinin on flower sex determination by exogenous application of 6-benzyladenine (BA) in P. volubilis. The floral development of P. volubilis was divided into eight stages, and the first morphological divergence between the male and female flowers was found to occur at stage 3. Both female and male flowers can be structurally distinguished by differences in the shape and size of the flower apex after sepal primordia initiation. There are no traces of gynoecia in male flowers or of androecia in female flowers. Exogenous application of BA effectively induced gynoecium primordia initiation and female flower development, especially at the early flower developmental stages. We propose that flower sex is determined earlier and probably occurs before flower initiation, either prior to or at inflorescence development due to the difference in the position of the female and male primordia in the inflorescence and in the time of the female and male primordia being initiated. The influence of cytokinin on female primordia during flower development in P. volubilis strongly suggests a feminization role for cytokinin in sex determination. These results indicate that cytokinin could modify the fate of the apical meristem of male flower and promote the formation of carpel primordia in P. volubilis.

中文翻译：

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花性测定的发展基础以及细胞分裂素对Volkenetia volubilis（Euphorbiaceae）中性测定的影响。

关键信息

细胞分裂素可能是在sacha inchi花发育的早期调节花性的重要因素。

抽象

Sacha inchi（Plukenetia volubilis，Euphorbiaceae）的特征是在锡菊中有雌花和雄花，但有特定的差异。对单性花发育的机制了解得很少。在这项研究中，利用光学显微镜和扫描电子显微镜研究了野性假单胞菌的花序和花发育。我们还研究了外源应用6-苄腺嘌呤（BA）伏牛体育中细胞分裂素对花性的影响。山茱P的花期发育将其分为八个阶段，发现雄花和雌花之间的第一个形态差异发生在第3阶段。雌花和雄花的结构可以通过萼片原基萌生后花尖的形状和大小的差异来区分。在雄花中没有雌蕊的痕迹，在雌花中没有雄蕊的痕迹。外源施用BA有效诱导了雌蕊原基萌发和雌花发育，特别是在花的早期发育阶段。我们建议花性较早确定，并且可能由于花序中雌，雄原基在花序中的位置以及雌，雄原基被启动的时间的不同，而在花生前或花序发育之前发生。 。野性假单胞菌强烈暗示了细胞分裂素在性别确定中的女性化作用。这些结果表明细胞分裂素可以修饰雄花顶生分生组织的命运，并促进卷心菜原基的形成。