Growth and fructan content of plants of Vernonia herbacea (Asteraceae) regenerated from rhizophores

Abstract

SUMMARYThe growth and fructan contents of plants of Vernonia herbacea (Veil.) Rusby regenerated from fragments of the underground organ (rhizophore) were analysed during two developmental cycles. When cultivated away from their natural ecosystem, these plants went through the same phenological phases as those naturally grown in the cerrado. The first aerial shoots started developing from initial fragments before the new underground system, the former acting as the main metabolic sink for the fructan present in the initial fragments. The new rhizophores started to develop by the sixth month, as photosynthates were transformed into fructans. Growth parameters measured reached higher values in the second growth cycle, exhibiting growth curves synchronized with those obtained for fructan contents in the new rhizophores. Fructo-oligosaccharides were available mostly during the period of fast growth of aerial organs whilst the fructo-polysaccharides were reduced. Fructan variation indicates that these compounds are metabolized during development. Additionally, the rapid growth, intense production of rhizophores and high fructan content make Vernonia herbacea a promising source of fructan for commercial use.

Growth, photosynthate partitioning and fructan accumulation in plants of Vernonia herbacea (Vell.) Rusby under two nitrogen levels

“…Rusby were obtained from rhizophores as described in Carvalho et al (1997). Fifty-dayold plants of about 5 cm high were selected and transferred to plastic pots (3 L) containing washed sand.…”

Fructan variation in the rhizophores of Vernonia herbacea (Vell.) Rusby, as influenced by temperature

“…Rusby (Asteraceae), obtained through vegetative propagation, according to Carvalho et al (1997) and cultivated in individual pots under natural environmental conditions, were used in the experiments.…”

Fructans and water suppression on intact and fragmented rhizophores of Vernonia herbacea

“…However, as information concerning fructan mediated drought tolerance in transgenic plants was obtained with the introduction of a bacterial enzyme, it could be controversial among plant physiologists. Vernonia herbacea (Asteraceae) is native to the cerrado vegetation and presents a well defined seasonal pattern of growth within the annual cycle (Carvalho and Dietrich, 1993;Carvalho et al, 1997). Similar to various other herbaceous Asteraceae from the cerrado (Tertuliano and Figueiredo-Ribeiro, 1993), plants of this species accumulate high levels of fructans of the inulin type in the underground storage organs (Carvalho and Dietrich, 1993).…”