Stomatal closure prevents xylem transport of green leaf volatiles and impairs their systemic function in plants.

Abstract

Plants perceive environmental stresses as whole organisms via distant signals conveying danger messages through their vasculature. In parallel to vascular transport, airborne plant volatile compounds, including green leaf volatiles (GLVs), can bypass the lack of vascular connection. However, some small volatile compounds move through the vasculature; such vascular transport is little known about GLVs. Here we illustrate GLV alcohols as solutes move within xylem vessels in Zea mays. We describe GLV alcohols, including Z-3-hexen-ol and its isomer E-3-hexen-ol, which is not synthesized in maize, moving through the transpiration stream via xylem vessels. Since transpiration is mediated by the stomatal aperture, closing stomata by two independent methods diminishes the transport of GLV alcohol and its isomer. In addition, the lower transport of GLV alcohols impairs their function in inducing terpenoid biosynthesis, suggesting that xylem transport of GLV alcohols plays a significant role in their systemic function. Our study suggests that GLV alcohols, in addition to airborne signals, are transported through xylem vessels. Our findings can be critical in future studies about the perception and function of these compounds in plants.