Fructan dynamics in the underground organs of Chresta exsucca (Asteraceae), a dry season flowering species

Abstract

Climatic seasonality has an infl uence on the phenology of native Cerrado plants. Herbs and subshrubs tend to fl ower in the rainy season, although some species of these habits fl ower in the dry season. Reserve carbohydrates, stored in the underground organs, are used to support phases of high energy-demand, but also may protect plants from damage during periods of environmental limitation. In this study we evaluated variation in fructan levels in the underground organs of fi eld-grown plants of Chresta exsucca among diff erent phenological phases. Chresta exsucca fl owers in the dry season and possesses a diff use underground system, which stores inulin-type fructans. Resprouting was continual during the sampling period. Oligosaccharide content was always higher than polysaccharide content, except during senescence, the only phase with an oligosaccharide: polysaccharide ratio < 1. Fructan accumulation occurred during vegetative growth until fl owering. Fructan mobilization was prominent during resprouting until the beginning of vegetative growth. Fructans stored in the underground organs of C. exsucca serve to fulfi ll the energetic demands of development and maintenance of this complex structure. In this way, fructans are essential to the persistence of this species in the environment of the Cerrado by ensuring reproduction in harsh conditions, such as drought.

PHENOLOGY, REPRODUCTIVE BIOLOGY AND SPATIAL DISTRIBUTION OF Chresta scapigera (LESS.) Gardner (ASTERACEAE)

“…from the genus Chresta), which occur in Cerrado sites in Serra Dourada, Goiás state, also concentrate flowering in the driest and windiest season. In another study, Santos et al (2018) also observed flowering during the dry season in Cerrado for the species Chresta exsucca D.C. in Goiás. Thus, the observed concentration of flowering and immature fruit production of C. scapigera in the dry season might be related to an anemochoric strategy to increase its pollination and dispersal success, though further study is necessary to confirm this assumption.…”

Órgãos subterrâneos de Espada de São Jorge são fontes promissoras de frutanos

“…Os extratos foram filtrados em filtros (0,45 μm) conectados em seringas, e em seguida foram injetados no cromatógrafo de troca aniônica de alto desempenho com detecção por pulso amperométrico (HPAEC-PAD), em conjunto pré-coluna e coluna CarboPac PA-100 (4 x 250 mm). A eluição (1 mL.min -1 ) foi realizada em gradiente de acetato de sódio em hidróxido de sódio (100 mM) com a seguinte programação: 0-10 min: 5 mM; 10,1 -35min, 5 -50 mM; 35,1 -40 min, 50 -375 mM; 40,1 -45min, 500 mM (Santos et al, 2018). Para a identificação dos açúcares foram utilizados extratos de bulbos de Allium cepa, que possui a neossérie da inulina (Yamamori et al, 2015), e de rizóforos de Chrysolaena obovata que possui a série da inulina (Carvalho; Dietrich 1993) como padrões.…”