A Meta-analysis And Model Simulation Of Plant Ecophysiological Responses To Night Temperature Change

Land surface temperature over the past decades has shown a faster warming trend during the night than during the day. Extremely low night temperatures have occurred frequently due to the influence of land-sea thermal difference, topography and climate change. This asymmetric night temperature change is expected to affect plant ecophysiology and growth. However, the effects of high night temperature(HNT) and low night temperature (LNT) on plant ecophysiological and growing processes and how the effects vary among different plant functional types (PFTs)have not been analyzed extensively. In this study,we first exerted meta-analysis and found that the effects of night temperature on plant physiology and growth varied between HNT and LNT, among the response variables and PFTs, and depended on the magnitude of temperature change and experimental design. Leaf growth was stimulated at HNT and suppressed at LNT. HNT accelerated plants ecophysiological processes, including photosynthesis and dark respiration, while LNT slowed these processes. However, we found that HNT and LNT both had a negative effect on plant yield, as the effect of HNT on plant yield was primarily related to a reduction in biomass allocation to reproduction organs and the effect of LNT on plant yield was more related to a negative effect on total biomass. These findings suggest complexities and challenges in seeking general patterns of terrestrial plant growth in HNT and LNT.Mathematicle model is a valuable tool to simulate the physiology and growth of plant. Previous simulation based on daily temperature variation usually ignored the effect of asymmetric night temeperature change, therefore, we utilized mechanistic crop model, BioCro, to simulate the response of plant biomass production to night temperature change. After validating the key modules of BioCro under night temperature variation, we simulated the biomass production of two typical bioenergy crops, Salix and Saccharum, in USA under ambient temeperature, elevated day, night and daily temperature. The results demonstrated that the effect of warming on two bioenergy crops varied with changing geographic location. For willow, increasing day temperature and daily temperature both decreased the biomass in the southeastern coastal areas and increased the yield in the northwestern USA,whereas night warming enhanced the yield of the northeastern, mid-northern and northwestern USA. But for sugarcane, increasing temperature had a consistent positive effect on the biomass production of main production areas in USA, Elevated day temperature and daily temperature created more increment of sugarcane yield in the middle-high latitude regions in the east and middle of America, while the yield in the south-eastern coastal areas of USA was increased under night warming. In general, elevated night temperature had a positive effect on the yield of willow and sugarcane for the contiguous USA, which was corresponding to the result of the meta-analysis. Our study is critical for agricultural production prediction, greenhouse gas regulation and environment management, as well as extending the knowledge of the changes in crop production, plant community structure, vegetation dynamics,biodiversity, and ecosystem functioning of terrestrial biomes when asymmetric night temperature change continues.