Harvest Initiated Volatile Organic Compound Emissions from In-Field Tall Wheatgrass

Area of Science:

• Plant Biology and Ecology
• Atmospheric Chemistry
• Biofuel Research

Background:

• Increasing crop and grassland use necessitates understanding plant-specific volatile organic compounds (VOCs) emissions.
• VOCs from ecosystems impact atmospheric chemistry and carbon cycling, with biofuel production potentially altering these emissions.
• Tall wheatgrass (Thinopyrum ponticum) is a promising biofuel candidate due to its resilience.

Purpose of the Study:

• To evaluate the diversity of VOCs emitted by "Alkar" tall wheatgrass pre- and post-harvest.
• To identify distinct volatilomes associated with different harvest conditions.
• To assess the implications of these VOC emissions for atmospheric chemistry and carbon cycling in the context of biofuel production.

Main Methods:

• Field-grown mature tall wheatgrass plants (n=6) were sampled for VOCs.
• Sampling occurred both before and after harvest in October 2022.
• Hierarchical clustering was used to analyze the diversity of emitted VOCs (volatilomes).

Main Results:

• Distinct volatilomes were observed for pre- and post-harvest conditions, despite plant-to-plant variability.
• Fifty VOCs were unique to the post-harvest volatilome, comprising 26% of the total post-harvest signal.
• Green leaf volatiles (GLVs) dominated post-harvest emissions, but novel VOCs like 3-octanone were also identified.

Conclusions:

• Harvesting significantly alters the VOC emission profile of tall wheatgrass.
• The study identified unique post-harvest VOCs, some of which are under-characterized regarding atmospheric impacts.
• Further quantitative flux analysis is needed to fully understand the biofuel potential and environmental impact of tall wheatgrass.