title: Elevated night-time temperatures increase growth in seedlings of two tropical pioneer tree species.
abstract: Increased night-time temperatures, through their influence on dark respiration, have been implicated as a reason behind decreasing growth rates in tropical trees in the face of contemporary climate change. Seedlings of two neo-tropical tree species (Ficus insipida and Ochroma pyramidale) were grown in controlled-environment chambers at a constant daytime temperature (33°C) and a range of increasing night-time temperatures (22, 25, 28, 31°C) for between 39 d and 54 d. Temperature regimes were selected to represent a realistic baseline condition for lowland Panama, and a rise in night-time temperatures far in excess of those predicted for Central America in the coming decades. Experiments were complemented by an outdoor open-top chamber study in which night-time temperatures were elevated by 2.4°C above ambient. Increasing night-time temperatures resulted in > 2-fold increase in biomass accumulation in growth-chamber studies despite an increase in leaf-level dark respiration. Similar trends were seen in open-top chambers, in which elevated night-time temperatures resulted in stimulation of growth. These findings challenge simplistic considerations of photosynthesis-directed growth, highlighting the role of temperature-dependent night-time processes, including respiration and leaf development as drivers of plant performance in the tropics.
authors.affiliation: Smithsonian Tropical Research Institute, Apartado, 0843-03092, Balboa, Ancón, Republic of Panama.
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Cheesman
authors.affiliation: Smithsonian Tropical Research Institute, Apartado, 0843-03092, Balboa, Ancón, Republic of Panama.
authors.forename: Klaus
authors.initials: K
authors.lastname: Winter
mesh_terms: D035161:Bombacaceae / Q000254:growth & development* / Q000502:physiology; D057231:Climate Change; D030681:Ficus / Q000254:growth & development* / Q000502:physiology; D017440:Photoperiod; D010788:Photosynthesis; D036226:Seedlings / Q000254:growth & development / Q000502:physiology; D013696:Temperature; D013997:Time Factors; D014329:Tropical Climate