Desenvolvimento de óvulos de Caryocaraceae e sua importância na sistemática e evolução de Malpighiales

Abstract

Embryology is an area of study that originated from the curiosity to understand the processes involved in the sexual reproduction of plants. It currently encompasses the study of characteristics present in the formation of micro- and megagasporangia, spores, gametophytes and gametes, and associated structures. Among these processes, it is possible to raise a large number of characters that have taxonomic applications. However, the number of groups whose embryology is known is small and we can highlight, among these, the family Caryocaraceae Voigt. Caryocaraceae is composed of 26 species distributed in two genera, Caryocar L. and Anthodiscus G. Mey. It is currently inside Malpighiales, where its exact placement remains unclear. Thus, our study aims to reduce these gaps by studying the processes of megasporogenesis and megamatetogenesis in Caryocar brasiliense Camb. For this, flowering, anthesis, post-anthesis, at different stages of development, in pre-products and fruits. The material was sectioned in a microrotary, the slides were supplied with stained and mounted. C. brasiliense the campylotrope egg, bitegmic and crassinucellated. Vascularization is branched and has not gone beyond the chalaza. Hypostasis and endothelium are present, and modification of the nucellus to form the nucellar cap. The presence of phenolic compounds in the teguments is observed. Micropyle it is only the internal integument that is absent, and the obturator is absent. The development is of the Polygonum type. Our results were compared with phylogenetically related families. The absence of the obturator in Caryocaraceae also occurred in Elatinaceae, Balanopaceae, Chrysobalanaceae and Trigoniaceae. The megasporogenesis of relational families presented common characteristics for most families. In relation to Putranjivaceae, the most relevant similarity was the presence of endothelium. The presence of nucellar capacity and branched vascularization were unique features. As future perspectives, we highlight the importance of complementary studies that investigate the development of the seed and the embryo for Caryocaraceae, as well as the unitegumentary ovule in Anthodiscus.