Thermogenesis of three species of Arum from Crete

• Published in: Plant, cell and environment cell and environment, 2009-10, Vol.32 (10), p.1467-1476
• Main Authors: SEYMOUR, ROGER S., GIBERNAU, MARC, PIRINTSOS, STERGIOS ARG
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Animal biology; Araceae; Arum - physiology; arum lily; Biological and medical sciences; Biology and morphogenesis of the reproductive apparatus. Photoperiodism, vernalisation; Botanics; Carbon Dioxide - metabolism; Flowers - physiology; Fundamental and applied biological sciences. Psychology; Greece; inflorescence; Life Sciences; Plant physiology and development; pollination; Temperature; temperature regulation; Vegetal Biology; Vegetative and sexual reproduction, floral biology, fructification
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/j.1365-3040.2009.02015.x

ABSTRACT Inflorescences of arum lilies have a three‐part spadix with a scent‐producing, sterile appendix above two bands of fertile male and female florets. The appendix and male florets are thermogenic, but with different temporal patterns. Heat‐production was measured in Arum concinnatum, A. creticum and A. idaeum. The male florets of A. concinnatum showed a 3 d continuous episode of thermogenesis with three waves, and the appendix warmed in a single, 6 h episode. Maximum fresh‐mass‐specific CO2 production rate was 0.17 µmol s−1 g−1 to achieve a 10.9 °C temperature elevation by the appendix, and 0.92 µmol s−1 g−1 to achieve a 4.8 °C elevation by male florets. Reversible, physiological temperature regulation was not evident in either tissue. Respiration increased with tissue temperatures with Q10 values of 1.8–3.9, rather than less than 1.0 as occurs in thermoregulatory flowers. Experimental step changes in temperature of appendix and male floret tissues also failed to show thermoregulatory responses. The patterns of thermogenesis therefore appear to be fixed by the temporal sequence of blooming. Thermogenesis in the alpine species, A. creticum and A. idaeum, was significantly lower than in the lowland A. concinnatum, possibly related to difficulty in raising floral temperature in their cold and windy habitat.