Anatomy and fructan distribution in vegetative organs of Dimerostemma vestitum (Asteraceae) from the campos rupestres

Abstract

Among the compounds stored by plants, several functions are assigned to fructans, such as source of energy and protection against drought and extreme temperatures. In the present study we analyzed the anatomy and distribution of fructans in vegetative organs of Dimerostemma vestitum (Asteraceae), an endemic species from the Brazilian campos rupestres. D. vestitum has amphistomatic and pubescent leaves, with both glandular and non-glandular trichomes. In the basal aerial stem the medulla has two types of parenchyma, which differ from the apical portion. The xylopodium has mixed anatomical origin. Interestingly, although inulin-type fructans with high degree of polymerization were found in all analyzed organs except the leaves, the highest amount and maximum degree of polymerization were detected in the xylopodium. Inulin sphero-crystals were visualized under polarized light in the medulla and in the vascular tissues mainly in the central region of the xylopodium, which has abundant xylem parenchyma. Secretory structures accumulating several compounds but not inulin were identified within all the vegetative organs. The presence of these compounds, in addition to inulin, might be related to the strategies of plants to survive adverse conditions in a semi-arid region, affected seasonally by water restriction and frequently by fire.

A high‐throughput method using Ultra‐Performance Liquid Chromatography to determine water‐soluble carbohydrate concentrations in pasture plants

“…Conversely, the 0–5 cm fraction had the lowest concentration of sucrose and highest concentration of fructan. The observed reduction in fructan concentration in plant height is in line with the findings of Sprague and Sullivan () and Silva, Vilhalva, Moraes, and Figueiredo‐Ribeiro (). Sprague and Sullivan () found that the fructan concentration in orchard grass ( Dactylis glomerata ) was highest in lower stem followed by upper stem and upper leaf blades had the least concentration of fructans.…”

Leaf and stem anatomy and essential oil composition of four Brazilian Aldama species (Asteraceae) and their taxonomic significance

“…Inulin crystals (fructans) were detected only in the stem of A. pilosa. This carbohydrate is typical in the underground organs of Asteraceae species (Figueiredo-Ribeiro 1993;Silva et al 2015;Abdalla et al 2016;Moraes et al 2016) and has already been reported, but only in tuberous roots of Aldama (Oliveira et al 2013;Silva et al 2014;Bombo et al 2014). It is well known that fructan storage enables plants to tolerate stress conditions, such as drought (Valluru and Van den Ende 2008;Vilhalva et al 2011;Oliveira et al 2013) and low temperatures (Hendry 1987;Pontis 1989;Vijn and Smeekens 1999;Portes et al 2008), both common environmental conditions in the regions in which A. pilosa is usually found.…”