title: High temperatures limit plant growth but hasten flowering in root chicory (Cichorium intybus) independently of vernalisation.
abstract: An increase in mean and extreme summer temperatures is expected as a consequence of climate changes and this might have an impact on plant development in numerous species. Root chicory (Cichorium intybus L.) is a major crop in northern Europe, and it is cultivated as a source of inulin. This polysaccharide is stored in the tap root during the first growing season when the plant grows as a leafy rosette, whereas bolting and flowering occur in the second year after winter vernalisation. The impact of heat stress on plant phenology, water status, photosynthesis-related parameters, and inulin content was studied in the field and under controlled phytotron conditions. In the field, plants of the Crescendo cultivar were cultivated under a closed plastic-panelled greenhouse to investigate heat-stress conditions, while the control plants were shielded with a similar, but open, structure. In the phytotrons, the Crescendo and Fredonia cultivars were exposed to high temperatures (35°C day/28°C night) and compared to control conditions (17°C) over 10 weeks. In the field, heat reduced the root weight, the inulin content of the root and its degree of polymerisation in non-bolting plants. Flowering was observed in 12% of the heat stressed plants during the first growing season in the field. In the phytotron, the heat stress increased the total number of leaves per plant, but reduced the mean leaf area. Photosynthesis efficiency was increased in these plants, whereas osmotic potential was decreased. High temperature was also found to induced flowering of up to 50% of these plants, especially for the Fredonia cultivar. In conclusion, high temperatures induced a reduction in the growth of root chicory, although photosynthesis is not affected. Flowering was also induced, which indicates that high temperatures can partly substitute for the vernalisation requirement for the flowering of root chicory.
authors: Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute, Université catholique de Louvain, 5 (bte L7.07.13) Place Croix du Sud, 1348 Louvain-la-Neuve, Belgium.
authors: Anne-Sophie
authors: AS
authors: Mathieu
authors: Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute, Université catholique de Louvain, 5 (bte L7.07.13) Place Croix du Sud, 1348 Louvain-la-Neuve, Belgium.
authors: Stanley
authors: S
authors: Lutts
authors: Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute, Université catholique de Louvain, 5 (bte L7.07.13) Place Croix du Sud, 1348 Louvain-la-Neuve, Belgium.
authors: Bertrand
authors: B
authors: Vandoorne
authors: Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute, Université catholique de Louvain, 5 (bte L7.07.13) Place Croix du Sud, 1348 Louvain-la-Neuve, Belgium.
authors: Christophe
authors: C
authors: Descamps
authors: Université de Liège, Département des Sciences de la Vie PhytoSYSTEMS, Laboratoire de Physiologie Végétale, 27 Boulevard du Rectorat (Bât 22), 4000 Liège, Belgium.
authors: Claire
authors: C
authors: Périlleux
authors: Chicoline - Research and Chicory Breeding, S.A. Warcoing, rue de la Sucrerie 2, B-7740 Warcoing, Belgium.
authors: Vincent
authors: V
authors: Dielen
authors: Chicoline - Research and Chicory Breeding, S.A. Warcoing, rue de la Sucrerie 2, B-7740 Warcoing, Belgium.
authors: Jean-Claude
authors: JC
authors: Van Herck
authors: Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute, Université catholique de Louvain, 5 (bte L7.07.13) Place Croix du Sud, 1348 Louvain-la-Neuve, Belgium. Electronic address: muriel.quinet@uclouvain.be.
authors: Muriel
authors: M
authors: Quinet
mesh_terms: D050260:Carbohydrate Metabolism; D018651:Cichorium intybus / Q000254:growth & development*; D035264:Flowers / Q000254:growth & development*; D006358:Hot Temperature; D010788:Photosynthesis; D014867:Water / Q000502:physiology
chemical_list: D014867:Water
keywords: 1-FEH; 1-FFT; 1-kestose fructan:fructan 1-fructosyltransferase (EC 2.4.1.100); A; Chla; Chlb; CiFL1; Cichorium intybus; Cichorium intybus FLC-LIKE1; DP; DW; E; FLC; FLM; FLOWERING LOCUS C; FLOWERING LOCUS M; FM2; FW; Flowering; Fs; High temperatures; IP; Inulin; NPQ; PAR; Root chicory; WC; chlorophyll a; chlorophyll b; dry weight; fluorescence monitoring system II; fresh weight; fructan 1-exohydrolase (EC 3.2.1.153); g(s); instantaneous CO(2) assimilation; instantaneous transpiration; inulin percentage; leaf stomatal conductance; mean inulin degree of polymerisation; non-photochemical-quenching; osmotic potential; photochemical quenching; photosynthetically active radiation; photosystemII efficiency; qP; steady state level of fluorescence; water content; Ψs; φ(PSII)