Elevated temperature may accelerate invasive expansion of the liana plant Ipomoea cairica
Wang R-L; Zeng R-S; Peng S-L; Chen B-M; Liang X-T
Numerous studies have shown that elevated CO2 levels promote liana establishment in forests thus suggesting their increased prevalence in the future in these habitats. Limited information exists however concerning the effects of potentially increasing global temperatures on these plants. The invasive liana Ipomoea cairica has infested many forests in South China. We hypothesised that elevated temperature could change the resource allocation pattern and allelopathic potential of this plant resulting in increased invasiveness. We compared seed germination growth rates and leachate phytotoxicity of I. cairica at three temperatures (22 26 and 30°C). The seed germination rates of I. cairica were 11.6% 21.2% and 26.4% at 22 26 and 30°C respectively. Elevated temperature resulted in significant changes in morphology and biomass allocation of I. cairica. Shoot biomass of the plant increased while the root biomass decreased with increasing temperature. Phytotoxicity of aqueous leachates from fresh leaves of I. cairica varied depending on receptor plants but showed the strongest phytotoxic effects at the highest temperature (30°C). Our results provide key information concerning the effects of elevated temperatures on the allelopathic potential germination and growth of I. cairica and indicate that global warming could increase the invasiveness of this species.