Leaf Dynamics of Panicum maximum under Future Climatic Changes

Author(s)

Britto de Assis Prado, Carlos Henrique ^[1] ; Guedes de Camargo-Bortolin, Livia Haik ^[1] ; Castro, Erique ^[1] ; Martinez, Carlos Alberto ^[2]

Affiliation

^[1] Univ Fed Sao Paulo, Dept Bot, BR-13565905 Sao Paulo - Brazil

^[2] Univ Sao Paulo, FFCLRP, Dept Biol, BR-14040901 Sao Paulo - Brazil

• Document type: Journal article
• Source: PLoS One; v. 11, n. 2 FEB 19 2016.
• Web of Science Citations: 6

Abstract

Panicum maximum Jacq. `Mombaca' (C4) was grown in field conditions with sufficient water and nutrients to examine the effects of warming and elevated CO2 concentrations during the winter. Plants were exposed to either the ambient temperature and regular atmospheric CO2 (Control); elevated CO2 (600 ppm, eC); canopy warming (+2 degrees C above regular canopy temperature, eT); or elevated CO2 and canopy warming (eC+eT). The temperatures and CO2 in the field were controlled by temperature free-air controlled enhancement (T-FACE) and mini free-air CO2 enrichment (miniFACE) facilities. The most green, expanding, and expanded leaves and the highest leaf appearance rate (LAR, leaves day(-1)) and leaf elongation rate (LER, cm day(-1)) were observed under eT. Leaf area and leaf biomass were higher in the eT and eC+ eT treatments. The higher LER and LAR without significant differences in the number of senescent leaves could explain why tillers had higher foliage area and leaf biomass in the eT treatment. The eC treatment had the lowest LER and the fewest expanded and green leaves, similar to Control. The inhibitory effect of eC on foliage development in winter was indicated by the fewer green, expanded, and expanding leaves under eC+ eT than eT. The stimulatory and inhibitory effects of the eT and eC treatments, respectively, on foliage raised and lowered, respectively, the foliar nitrogen concentration. The inhibition of foliage by eC was confirmed by the eC treatment having the lowest leaf/stem biomass ratio and by the change in leaf biomass-area relationships from linear or exponential growth to rectangular hyperbolic growth under eC. Besides, eC+ eT had a synergist effect, speeding up leaf maturation. Therefore, with sufficient water and nutrients in winter, the inhibitory effect of elevated CO2 on foliage could be partially offset by elevated temperatures and relatively high P. maximum foliage production could be achieved under future climatic change. (AU)

• FAPESP's process: 08/58075-8 - Miniface climate-change impact experiment to analyze the effects of elevated CO2 and warming on photosynthesis, gene expression, biochemistry, growth, nutrient dynamics and yield of two contrasting tropical forage species
• Grantee: Carlos Alberto Martinez y Huaman
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 12/20847-5 - Growth, biomass and efficient use of nutrients in C3 and C4 forages species evaluated by MiniFACE
• Grantee: Lívia Haik Guedes de Camargo Bortolin
• Support Opportunities: Scholarships in Brazil - Doctorate