Elevated night‐time temperatures increase growth in seedlings of two tropical pioneer tree species
2013
Cheesman, Alexander W. | Winter, Klaus
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.
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