Articles
INFLUENCE OF SHADING ON FLOWERING INDUCTION AND INULIN METABOLISM IN ROOTS OF CYNARA CARDUNCULUS L.
Article number
983_60
Pages
415 – 420
Language
English
Abstract
Inulin-type fructan is a fructose polymer that has mostly or exclusively the β (2 →1) fructosyl-fructose linkage.
In higher plants this carbon source plays an important role in osmoregulation and crioprotection.
The storage of fructans (inulin and water soluble sugars) in underground organs of Cynara cardunculus grown in Mediterranean environment represents an adaptive strategy to overcome the Mediterranean unfavorable conditions.
Moreover, the variation in dry matter accumulation is strictly correlated with inulin synthesis and breakdown in roots and inulin metabolizing enzyme activities.
Since it has been shown that the maximum accumulation in roots happens just before flower formation, the aim of this work was to evaluate differences in inulin content and inulin metabolizing enzymes in roots of C. cardunculus var. sylvestris Lam. grown under two different treatments to obtain plants with flower induction (F) or not (WF). The experiments were carried out at Catania (south Italy, 37°27N; 15°4E, 10 m a.s.l.) during 2005-2006. One wild cardoon Sicilian population S3, was sown in pots (35 cm diameter), containing soil as substrate, for a total of 200 pots.
The sowing was performed in October 2005. Half of the plants were grown in open air (F), the other half was placed under shade clothes (WF). Plants were harvested every fifteen days from March to June 2006 for a total of 7 samplings.
For each harvest total biomass, including roots, was immediately weighed to determine the fresh weight (FW). Corresponding to each sampling, the root sugar characterization (glucose, fructose, sucrose and inulin), and the enzyme activities of sucrose:sucrose 1-fructosyl transferase (1-SST; EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (1-FFT, EC 2.4.1.100) and fructan 1-exohydrolase (1-FEH; EC 3.2.1.80) were analyzed.
Results showed that the WF plants accumulated higher inulin content in roots than F plants and this result is correlated with the 1-FFT activity, the enzyme responsible of elongation of fructose chain of inulin-type fructans.
In higher plants this carbon source plays an important role in osmoregulation and crioprotection.
The storage of fructans (inulin and water soluble sugars) in underground organs of Cynara cardunculus grown in Mediterranean environment represents an adaptive strategy to overcome the Mediterranean unfavorable conditions.
Moreover, the variation in dry matter accumulation is strictly correlated with inulin synthesis and breakdown in roots and inulin metabolizing enzyme activities.
Since it has been shown that the maximum accumulation in roots happens just before flower formation, the aim of this work was to evaluate differences in inulin content and inulin metabolizing enzymes in roots of C. cardunculus var. sylvestris Lam. grown under two different treatments to obtain plants with flower induction (F) or not (WF). The experiments were carried out at Catania (south Italy, 37°27N; 15°4E, 10 m a.s.l.) during 2005-2006. One wild cardoon Sicilian population S3, was sown in pots (35 cm diameter), containing soil as substrate, for a total of 200 pots.
The sowing was performed in October 2005. Half of the plants were grown in open air (F), the other half was placed under shade clothes (WF). Plants were harvested every fifteen days from March to June 2006 for a total of 7 samplings.
For each harvest total biomass, including roots, was immediately weighed to determine the fresh weight (FW). Corresponding to each sampling, the root sugar characterization (glucose, fructose, sucrose and inulin), and the enzyme activities of sucrose:sucrose 1-fructosyl transferase (1-SST; EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (1-FFT, EC 2.4.1.100) and fructan 1-exohydrolase (1-FEH; EC 3.2.1.80) were analyzed.
Results showed that the WF plants accumulated higher inulin content in roots than F plants and this result is correlated with the 1-FFT activity, the enzyme responsible of elongation of fructose chain of inulin-type fructans.
Authors
M.G. Melilli, S.A. Raccuia
Keywords
wild cardoon, fructans, inulin metabolizing enzymes, mean degree of polymerization
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