Instituto de Botánica del Nordeste, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional del Nordeste, Sargento Cabral 2131, CC 209, Corrientes, 3400, Argentina.
Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Sargento Cabral 2131, CC 209, Corrientes, 3400, Argentina.
J Plant Res. 2024 Nov;137(6):1061-1072. doi: 10.1007/s10265-024-01579-4. Epub 2024 Sep 16.
Previous studies have determined that Chloroluma gonocarpa (Sapotaceae), is a species that has cryptic dioecy. This type of sexual system is characterized by flowers that are morphologically perfect (both sexual whorls are present) but functionally pistillate or staminate (in each type of flower one of the sexual whorls is non-functional). In C. gonocarpa the pistillate flowers present well-developed stigma, functional ovules, and staminodes, while the staminate flowers present a poorly developed stigma, collapsed ovules, and pollen-producing anthers. In angiosperms, the abortion of sexual organs can occur at different stages of development (from pre-meiosis to post-meiosis), that is why we conducted an anatomical analysis of both flower types at various developmental stages. Using light microscopy, we described the processes of sporogenesis and gametogenesis to establish when the staminate flowers lose their pistillate function. To achieve this, we collected, fixed, and processed the flowers following conventional anatomical techniques for observation under a light microscope. Our findings reveal that pollen development occurs only in staminate flowers, while ovule development begins in both types of flowers but ceases in staminate flowers due to post-meiosis abortion. In contrast, normal development continues in pistillate flowers. These results suggest that dioecy in C. gonocarpa may have arisen from a gynodioecious pathway.
先前的研究已经确定，Chloroluma gonocarpa（山榄科）是一种具有隐性雌雄异熟的物种。这种性系统的特点是花朵在形态上是完美的（两性花被完整存在），但在功能上是雌性或雄性（在每一种花中，其中一性花被是无功能的）。在 C. gonocarpa 中，雌性花具有发育良好的柱头、功能性胚珠和退化雄蕊，而雄性花具有发育不良的柱头、塌陷的胚珠和产生花粉的花药。在被子植物中，性器官的败育可能发生在不同的发育阶段（从减数分裂前到减数分裂后），这就是为什么我们对两种花型在不同的发育阶段进行了解剖学分析。使用光学显微镜，我们描述了孢子发生和配子发生的过程，以确定雄性花何时失去其雌性功能。为此，我们按照常规的解剖技术收集、固定和处理花朵，以便在光学显微镜下进行观察。我们的发现表明，花粉发育仅发生在雄性花中，而胚珠发育开始于两种花型，但由于减数分裂后败育，在雄性花中停止。相比之下，正常的发育在雌性花中继续。这些结果表明，C. gonocarpa 中的雌雄异熟可能是从雌性异熟途径产生的。
