Abstract Detail

Development and Structure

Gissi, Danilo Soares [1], Seixas, Diana Pacheco [2], Fortuna-Perez, Ana Paula [2], Rodrigues, Tatiane Maria [2].

Morphological and histochemical diversity of the secretory structures in leaves and stems of the Stylosanthes guianensis (Leguminosae, Papilionoideae) complex.

Plants of the genus Stylosanthes have economic importance with several of them being used as forage and they are known for producing secretions that confer a viscous and sticky aspect to the plant organs. However, detailed studies that elucidate the morphological nature of the secretory structures in the plant body are lacking. We aimed to identify and describe the secretory structures in the above-ground vegetative body of eleven taxa of the S. guianensis complex. Leaf and stem samples were fixed in FAA 50, processed according to usual techniques, and examined in light and scanning electron microscopy. Histochemical tests were performed using Sudan IV, ferric chloride, Wagner reagent, PAS, NADI’s reagent, and Ruthenium red. Long appendages with a dilated base and a tapered upper portion occurred on the surface of both stems and leaves in most of the taxa. The base of these appendages was covered by the epidermis and filled with isodiametric parenchyma cells, with thin pectin-cellulosic walls, dense cytoplasm, and large nuclei. The parenchyma cells from these appendages reacted positively for total lipids, terpenes, and polysaccharides. The median and apical portions of the appendages consisted of elongated cells with cutinized walls. Ontogenetic analysis revealed that such structures are emergences with secretory bases. Besides, in all studied taxa, elongated idioblasts containing mucilage were found immersed in the palisade parenchyma of the leaves and subjacent to the epidermis. On the lower side of the mesophyll, a layer of rounded to oval voluminous cells filled with phenolic compounds occurred between the spongy parenchyma and the epidermis. Phenolic idioblasts were also found in the pith of the stems. Hydrophilic compounds, such as polysaccharides, are assumed to function in water retention, carbohydrate storage, reduction of transpiration, protection against intensive radiation, and protection against herbivory. On the other hand, lipids, terpenes, and phenolic compounds are known to function in plant defense against herbivores and pathogens. Our results demonstrate substantial variation in the morphological and histochemical features of secretory structures in the S. guianensis complex, which may underlie a diversity of functions, allowing plants to successfully interact with their environments and making them suitable for foraging usage. (CAPES 001)

1 - São Paulo State University - UNESP, Institute of Biosciences - IBB, R. Prof. Dr. Antônio Celso Wagner Zanin, 250, Distrito de Rubião Junior, Botucatu, SP, 18618-689, Brazil
2 - São Paulo State University - UNESP, Institute of Biosciences - IBB, R. Prof. Dr. Antônio Celso Wagner Zanin, 250, Distrito de Rubião Junior, Botucatu, SP, 18618-689, Brasil

Keywords:
secretory emergences
leaflet blade
anatomy
Fabaceae
mucilage.

Presentation Type: Poster
Session: P1, Development and Structure Posters
Location: Virtual/Virtual
Date: Monday, July 19th, 2021
Time: 5:00 PM(EDT)
Number: P1DS013
Abstract ID:905
Candidate for Awards:Developmental and Structural Section best poster