Abstract
Widely distributed amphibious exotic plant species may respond plastically to water temperatures when submerged. Alternanthera philoxeroides, a highly flood-tolerant species, originates from tropical regions and has successfully invaded temperate regions. The wide distribution of this species suggests it can respond to flooding at different water temperatures. In this study, the plastic responses of A. philoxeroides plants to submergence at water temperatures of 10 °C, 20 °C and 30 °C were investigated. The A. philoxeroides plants had large pools of non-structural carbohydrates, which were readily mobilized upon submergence. Submergence hindered biomass accumulation and decreased the carbohydrate content level and respiration rate (P < 0.05). Water temperature had remarkable effects on shoot elongation, carbohydrate utilization and recovery growth. With decreasing water temperature, the respiration rate was lower and carbohydrate content decreased more slowly, but the post-submergence biomass accumulation was faster (P < 0.05), indicating a beneficial effect of low water temperature for recovery. However, high water temperatures accelerated shoot elongation (P < 0.05), which benefitted the submerged plants more if contact with air was restored. These results suggest that the species can respond to different water temperatures plastically, which may provide hints for its invasion success in regions with diverse climates.
Highlights
Distributed amphibious exotic plant species may respond plastically to water temperatures when submerged
The beneficial effects of biomass accumulation were investigated by a comparison between plants kept submerged and the plants that were allowed contact with free air (Fig. 3)
Our results indicate that the submerged A. philoxeroides plants responded plastically to the different water temperatures (Figs 1–5), which may enable this species to successfully invade in different climate zones with different flooding timing patterns
Summary
The pH of the water slightly decreased with decreasing water temperature, while both dissolved oxygen and carbon dioxide increased (Table 1). On day 16, the fructose concentration was very similar in plants at the three different water temperatures in stems (P > 0.05); in roots, it was highest at 10 °C and lowest at 20 °C (P < 0.05); in leaves, the fructose concentration was similar in plants at 10 °C and 20 °C and higher in plants at 30 °C (Fig. 4b,f and j, P < 0.05). From day 10 to day 13, the sucrose concentration in all tissues at all water temperatures increased sharply; in stems and in roots, it was at similar levels in plants at the three water temperatures (Fig. 4c and g, P > 0.05), but in leaves, it was highest in plants submerged at 30 °C and lowest at 10 °C (Fig. 4k). From day 13 to day 16, the respiration rate in plants submerged at different water temperatures remained more or less stable but was still highest in plants at 10 °C and lowest in plants at 30 °C (P < 0.05)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
