Vascular bundles in fruits of Sapium sebiferum (L.) Roxb. and their botanical implications

In modern botany, the carpel occupies a pivotal role in the understanding of angiosperms, but different interpretations of its nature have long existed. The traditional Macrosporophyll Theory suggests that angiosperm carpels are derived from the macrosporophyll, but the newly emerging Unifying Theory suggests that the carpel is a composite organ consisting of a leave and an ovule-bearing branch. In this study, the distribution of vascular bundles in the fruit of Sapium sebiferum (Euphorbiaceae) was studied using micro-CT. The results showed that the vascular bundles leading to the ovules are completely separate from those leading to the ovary wall, suggesting that they are of different origin. Such results contradict the Macrosporophyll Theory and are consistent with the predictions of the Unifying Theory.