Carbon Allocation Patterns into Proteins and Lipids Associated with Superior Tolerance of Perennial Grass to High Soil Temperature

Abstract

ABSTRACTPlant adaptation to heat stress may involve changes in C allocation within the plant. The objective of this study was to determine whether heat tolerance of C3 perennial grass species was associated with the alteration of C allocation to proteins and lipids under heat stress. We study the patterns of allocation of newly fixed C through photosynthesis to proteins and lipids of heat‐tolerant thermal Agrostis scabra Willd. and heat‐sensitive creeping bent grass (A. stolonifera L. ‘Penncross’) exposed to high soil temperatures at 37°C or control temperature at 20°C. The allocation patterns of newly fixed C during heat stress into proteins and lipids in various plant organs (shoots, crowns, and roots) were examined using the 14CO2 pulse‐chase labeling technique. High soil temperature reduced the allocation of newly fixed C into proteins and lipids in shoots and roots, resulting in a lower protein and lipid content than control plants for both grass species. The decline in the protein and lipid content and the decrease in the 14C allocation were less pronounced in thermal A. scabra than in A. stolonifera. The more efficient incorporation of newly fixed 14C into lipids and proteins could support the superior tolerance of thermal A. scabra to prolonged periods of high soil temperatures.