High Day and Night Temperature Stress Results in Lipid Alterations in Wheat Pollen.

Climate models predict greater increases in night temperatures than in day temperatures. Understanding how wheat (Triticum aestivum L.) plants under high day and night temperature stresses regulate lipid composition, to maintain stable membranes and generate appropriate signals, is critical to developing climate-resilient wheat varieties. The objective of this study was to quantify the effects of high day and/or night temperatures during flowering on pollen lipid profile of wheat. Winter wheat genotypes, Ventnor (heat tolerant) and Karl 92 (heat susceptible) were grown at optimum temperatures (25/15°C, maximum/minimum) until the onset of flowering. Thereafter, plants were exposed to high night (HN, 25/24°C), high day (HD, 35/15°C), high day and night (HDN, 35/24°C), or optimum temperatures for 12 days. We used an automated electrospray ionization-tandem mass spectrometry approach to measure 165 glycerolipids and sterol derivatives under optimum and high day and night temperatures in wheat pollen on the third day of stress. Preliminary results demonstrate that wheat pollen lipid composition is altered by heat stress and some lipids are particularly responsive to heat.